How to trigger gaming mode? Just open a game that is supported in games list
How to exit? Kill the game from recents, or simply back to homescreen
What does this gaming mode do?
- It limits big cluster maximum frequency to 2,0GHz, and little cluster
to values matching GPU frequencies as below:
+ 338MHz: 455MHz
+ 385MHz and above: 1053MHz
- As for the cluster freq limits, it overcomes heating issue while playing
heavy games, as well as saves battery juice
Big thanks to [kerneltoast] for the following commits on his wahoo kernel
5ac1e81d3de13e2c4554
Gaming control's idea was based on these
Signed-off-by: Diep Quynh <remilia.1505@gmail.com>
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Merge 4.9.197 into android-4.9-q
Changes in 4.9.197
KVM: s390: Test for bad access register and size at the start of S390_MEM_OP
s390/topology: avoid firing events before kobjs are created
s390/cio: avoid calling strlen on null pointer
s390/cio: exclude subchannels with no parent from pseudo check
KVM: nVMX: handle page fault in vmread fix
ASoC: Define a set of DAPM pre/post-up events
powerpc/powernv: Restrict OPAL symbol map to only be readable by root
can: mcp251x: mcp251x_hw_reset(): allow more time after a reset
crypto: qat - Silence smp_processor_id() warning
usercopy: Avoid HIGHMEM pfn warning
timer: Read jiffies once when forwarding base clk
watchdog: imx2_wdt: fix min() calculation in imx2_wdt_set_timeout
ieee802154: atusb: fix use-after-free at disconnect
cfg80211: initialize on-stack chandefs
ima: always return negative code for error
fs: nfs: Fix possible null-pointer dereferences in encode_attrs()
9p: avoid attaching writeback_fid on mmap with type PRIVATE
xen/pci: reserve MCFG areas earlier
ceph: fix directories inode i_blkbits initialization
ceph: reconnect connection if session hang in opening state
drm/amdgpu: Check for valid number of registers to read
thermal: Fix use-after-free when unregistering thermal zone device
fuse: fix memleak in cuse_channel_open
sched/core: Fix migration to invalid CPU in __set_cpus_allowed_ptr()
kernel/elfcore.c: include proper prototypes
tools lib traceevent: Do not free tep->cmdlines in add_new_comm() on failure
perf tools: Fix segfault in cpu_cache_level__read()
perf stat: Fix a segmentation fault when using repeat forever
perf stat: Reset previous counts on repeat with interval
crypto: caam - fix concurrency issue in givencrypt descriptor
coresight: etm4x: Use explicit barriers on enable/disable
cfg80211: add and use strongly typed element iteration macros
cfg80211: Use const more consistently in for_each_element macros
nl80211: validate beacon head
ASoC: sgtl5000: Improve VAG power and mute control
panic: ensure preemption is disabled during panic()
USB: rio500: Remove Rio 500 kernel driver
USB: yurex: Don't retry on unexpected errors
USB: yurex: fix NULL-derefs on disconnect
USB: usb-skeleton: fix runtime PM after driver unbind
USB: usb-skeleton: fix NULL-deref on disconnect
xhci: Fix false warning message about wrong bounce buffer write length
xhci: Prevent device initiated U1/U2 link pm if exit latency is too long
xhci: Check all endpoints for LPM timeout
usb: xhci: wait for CNR controller not ready bit in xhci resume
xhci: Increase STS_SAVE timeout in xhci_suspend()
USB: adutux: remove redundant variable minor
USB: adutux: fix use-after-free on disconnect
USB: adutux: fix NULL-derefs on disconnect
USB: adutux: fix use-after-free on release
USB: iowarrior: fix use-after-free on disconnect
USB: iowarrior: fix use-after-free on release
USB: iowarrior: fix use-after-free after driver unbind
USB: usblp: fix runtime PM after driver unbind
USB: chaoskey: fix use-after-free on release
USB: ldusb: fix NULL-derefs on driver unbind
serial: uartlite: fix exit path null pointer
USB: serial: keyspan: fix NULL-derefs on open() and write()
USB: serial: ftdi_sio: add device IDs for Sienna and Echelon PL-20
USB: serial: option: add Telit FN980 compositions
USB: serial: option: add support for Cinterion CLS8 devices
USB: serial: fix runtime PM after driver unbind
USB: usblcd: fix I/O after disconnect
USB: microtek: fix info-leak at probe
USB: dummy-hcd: fix power budget for SuperSpeed mode
usb: renesas_usbhs: gadget: Do not discard queues in usb_ep_set_{halt,wedge}()
usb: renesas_usbhs: gadget: Fix usb_ep_set_{halt,wedge}() behavior
USB: legousbtower: fix slab info leak at probe
USB: legousbtower: fix deadlock on disconnect
USB: legousbtower: fix potential NULL-deref on disconnect
USB: legousbtower: fix open after failed reset request
USB: legousbtower: fix use-after-free on release
staging: vt6655: Fix memory leak in vt6655_probe
iio: adc: ad799x: fix probe error handling
iio: light: opt3001: fix mutex unlock race
efivar/ssdt: Don't iterate over EFI vars if no SSDT override was specified
perf llvm: Don't access out-of-scope array
perf inject jit: Fix JIT_CODE_MOVE filename
CIFS: Gracefully handle QueryInfo errors during open
CIFS: Force revalidate inode when dentry is stale
CIFS: Force reval dentry if LOOKUP_REVAL flag is set
kernel/sysctl.c: do not override max_threads provided by userspace
staging: fbtft: Stop using BL_CORE_DRIVER1
Staging: fbtft: fix memory leak in fbtft_framebuffer_alloc
MIPS: Disable Loongson MMI instructions for kernel build
Fix the locking in dcache_readdir() and friends
media: stkwebcam: fix runtime PM after driver unbind
tracing/hwlat: Report total time spent in all NMIs during the sample
tracing/hwlat: Don't ignore outer-loop duration when calculating max_latency
tracing: Get trace_array reference for available_tracers files
x86/asm: Fix MWAITX C-state hint value
xfs: clear sb->s_fs_info on mount failure
Linux 4.9.197
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
commit b0f53dbc4bc4c371f38b14c391095a3bb8a0bb40 upstream.
Partially revert 16db3d3f11 ("kernel/sysctl.c: threads-max observe
limits") because the patch is causing a regression to any workload which
needs to override the auto-tuning of the limit provided by kernel.
set_max_threads is implementing a boot time guesstimate to provide a
sensible limit of the concurrently running threads so that runaways will
not deplete all the memory. This is a good thing in general but there
are workloads which might need to increase this limit for an application
to run (reportedly WebSpher MQ is affected) and that is simply not
possible after the mentioned change. It is also very dubious to
override an admin decision by an estimation that doesn't have any direct
relation to correctness of the kernel operation.
Fix this by dropping set_max_threads from sysctl_max_threads so any
value is accepted as long as it fits into MAX_THREADS which is important
to check because allowing more threads could break internal robust futex
restriction. While at it, do not use MIN_THREADS as the lower boundary
because it is also only a heuristic for automatic estimation and admin
might have a good reason to stop new threads to be created even when
below this limit.
This became more severe when we switched x86 from 4k to 8k kernel
stacks. Starting since 6538b8ea88 ("x86_64: expand kernel stack to
16K") (3.16) we use THREAD_SIZE_ORDER = 2 and that halved the auto-tuned
value.
In the particular case
3.12
kernel.threads-max = 515561
4.4
kernel.threads-max = 200000
Neither of the two values is really insane on 32GB machine.
I am not sure we want/need to tune the max_thread value further. If
anything the tuning should be removed altogether if proven not useful in
general. But we definitely need a way to override this auto-tuning.
Link: http://lkml.kernel.org/r/20190922065801.GB18814@dhcp22.suse.cz
Fixes: 16db3d3f11 ("kernel/sysctl.c: threads-max observe limits")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch adds polling support to pidfd.
Android low memory killer (LMK) needs to know when a process dies once
it is sent the kill signal. It does so by checking for the existence of
/proc/pid which is both racy and slow. For example, if a PID is reused
between when LMK sends a kill signal and checks for existence of the
PID, since the wrong PID is now possibly checked for existence.
Using the polling support, LMK will be able to get notified when a process
exists in race-free and fast way, and allows the LMK to do other things
(such as by polling on other fds) while awaiting the process being killed
to die.
For notification to polling processes, we follow the same existing
mechanism in the kernel used when the parent of the task group is to be
notified of a child's death (do_notify_parent). This is precisely when the
tasks waiting on a poll of pidfd are also awakened in this patch.
We have decided to include the waitqueue in struct pid for the following
reasons:
1. The wait queue has to survive for the lifetime of the poll. Including
it in task_struct would not be option in this case because the task can
be reaped and destroyed before the poll returns.
2. By including the struct pid for the waitqueue means that during
de_thread(), the new thread group leader automatically gets the new
waitqueue/pid even though its task_struct is different.
Appropriate test cases are added in the second patch to provide coverage of
all the cases the patch is handling.
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Daniel Colascione <dancol@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Tim Murray <timmurray@google.com>
Cc: Jonathan Kowalski <bl0pbl33p@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: kernel-team@android.com
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Co-developed-by: Daniel Colascione <dancol@google.com>
Signed-off-by: Daniel Colascione <dancol@google.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Christian Brauner <christian@brauner.io>
(cherry picked from commit b53b0b9d9a613c418057f6cb921c2f40a6f78c24)
Bug: 135608568
Test: test program using syscall(__NR_sys_pidfd_open,..) and poll()
Change-Id: I02f259d2875bec46b198d580edfbb067f077084e
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
This patchset makes it possible to retrieve pid file descriptors at
process creation time by introducing the new flag CLONE_PIDFD to the
clone() system call. Linus originally suggested to implement this as a
new flag to clone() instead of making it a separate system call. As
spotted by Linus, there is exactly one bit for clone() left.
CLONE_PIDFD creates file descriptors based on the anonymous inode
implementation in the kernel that will also be used to implement the new
mount api. They serve as a simple opaque handle on pids. Logically,
this makes it possible to interpret a pidfd differently, narrowing or
widening the scope of various operations (e.g. signal sending). Thus, a
pidfd cannot just refer to a tgid, but also a tid, or in theory - given
appropriate flag arguments in relevant syscalls - a process group or
session. A pidfd does not represent a privilege. This does not imply it
cannot ever be that way but for now this is not the case.
A pidfd comes with additional information in fdinfo if the kernel supports
procfs. The fdinfo file contains the pid of the process in the callers
pid namespace in the same format as the procfs status file, i.e. "Pid:\t%d".
As suggested by Oleg, with CLONE_PIDFD the pidfd is returned in the
parent_tidptr argument of clone. This has the advantage that we can
give back the associated pid and the pidfd at the same time.
To remove worries about missing metadata access this patchset comes with
a sample program that illustrates how a combination of CLONE_PIDFD, and
pidfd_send_signal() can be used to gain race-free access to process
metadata through /proc/<pid>. The sample program can easily be
translated into a helper that would be suitable for inclusion in libc so
that users don't have to worry about writing it themselves.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christian Brauner <christian@brauner.io>
Co-developed-by: Jann Horn <jannh@google.com>
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: David Howells <dhowells@redhat.com>
Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
(cherry picked from commit b3e5838252665ee4cfa76b82bdf1198dca81e5be)
Conflicts:
kernel/fork.c
(1. Replaced proc_pid_ns() with its direct implementation.)
Bug: 135608568
Test: test program using syscall(__NR_sys_pidfd_open,..) and poll()
Change-Id: I3c804a92faea686e5bf7f99df893fe3a5d87ddf7
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
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Merge 4.9.187 into android-4.9-q
Changes in 4.9.187
MIPS: ath79: fix ar933x uart parity mode
MIPS: fix build on non-linux hosts
arm64/efi: Mark __efistub_stext_offset as an absolute symbol explicitly
dmaengine: imx-sdma: fix use-after-free on probe error path
ath10k: Do not send probe response template for mesh
ath9k: Check for errors when reading SREV register
ath6kl: add some bounds checking
ath: DFS JP domain W56 fixed pulse type 3 RADAR detection
batman-adv: fix for leaked TVLV handler.
media: dvb: usb: fix use after free in dvb_usb_device_exit
crypto: talitos - fix skcipher failure due to wrong output IV
media: marvell-ccic: fix DMA s/g desc number calculation
media: vpss: fix a potential NULL pointer dereference
media: media_device_enum_links32: clean a reserved field
net: stmmac: dwmac1000: Clear unused address entries
net: stmmac: dwmac4/5: Clear unused address entries
signal/pid_namespace: Fix reboot_pid_ns to use send_sig not force_sig
af_key: fix leaks in key_pol_get_resp and dump_sp.
xfrm: Fix xfrm sel prefix length validation
media: mc-device.c: don't memset __user pointer contents
media: staging: media: davinci_vpfe: - Fix for memory leak if decoder initialization fails.
net: phy: Check against net_device being NULL
crypto: talitos - properly handle split ICV.
crypto: talitos - Align SEC1 accesses to 32 bits boundaries.
tua6100: Avoid build warnings.
locking/lockdep: Fix merging of hlocks with non-zero references
media: wl128x: Fix some error handling in fm_v4l2_init_video_device()
cpupower : frequency-set -r option misses the last cpu in related cpu list
net: fec: Do not use netdev messages too early
net: axienet: Fix race condition causing TX hang
s390/qdio: handle PENDING state for QEBSM devices
perf cs-etm: Properly set the value of 'old' and 'head' in snapshot mode
perf test 6: Fix missing kvm module load for s390
gpio: omap: fix lack of irqstatus_raw0 for OMAP4
gpio: omap: ensure irq is enabled before wakeup
regmap: fix bulk writes on paged registers
bpf: silence warning messages in core
rcu: Force inlining of rcu_read_lock()
blkcg, writeback: dead memcgs shouldn't contribute to writeback ownership arbitration
xfrm: fix sa selector validation
perf evsel: Make perf_evsel__name() accept a NULL argument
vhost_net: disable zerocopy by default
ipoib: correcly show a VF hardware address
EDAC/sysfs: Fix memory leak when creating a csrow object
ipsec: select crypto ciphers for xfrm_algo
media: i2c: fix warning same module names
ntp: Limit TAI-UTC offset
timer_list: Guard procfs specific code
acpi/arm64: ignore 5.1 FADTs that are reported as 5.0
media: coda: fix mpeg2 sequence number handling
media: coda: increment sequence offset for the last returned frame
mt7601u: do not schedule rx_tasklet when the device has been disconnected
x86/build: Add 'set -e' to mkcapflags.sh to delete broken capflags.c
mt7601u: fix possible memory leak when the device is disconnected
ath10k: fix PCIE device wake up failed
perf tools: Increase MAX_NR_CPUS and MAX_CACHES
libata: don't request sense data on !ZAC ATA devices
clocksource/drivers/exynos_mct: Increase priority over ARM arch timer
rslib: Fix decoding of shortened codes
rslib: Fix handling of of caller provided syndrome
ixgbe: Check DDM existence in transceiver before access
crypto: asymmetric_keys - select CRYPTO_HASH where needed
EDAC: Fix global-out-of-bounds write when setting edac_mc_poll_msec
bcache: check c->gc_thread by IS_ERR_OR_NULL in cache_set_flush()
iwlwifi: mvm: Drop large non sta frames
net: usb: asix: init MAC address buffers
gpiolib: Fix references to gpiod_[gs]et_*value_cansleep() variants
Bluetooth: hci_bcsp: Fix memory leak in rx_skb
Bluetooth: 6lowpan: search for destination address in all peers
Bluetooth: Check state in l2cap_disconnect_rsp
Bluetooth: validate BLE connection interval updates
gtp: fix Illegal context switch in RCU read-side critical section.
gtp: fix use-after-free in gtp_newlink()
xen: let alloc_xenballooned_pages() fail if not enough memory free
scsi: NCR5380: Reduce goto statements in NCR5380_select()
scsi: NCR5380: Always re-enable reselection interrupt
scsi: mac_scsi: Increase PIO/PDMA transfer length threshold
crypto: ghash - fix unaligned memory access in ghash_setkey()
crypto: arm64/sha1-ce - correct digest for empty data in finup
crypto: arm64/sha2-ce - correct digest for empty data in finup
crypto: chacha20poly1305 - fix atomic sleep when using async algorithm
crypto: crypto4xx - fix a potential double free in ppc4xx_trng_probe
Input: gtco - bounds check collection indent level
regulator: s2mps11: Fix buck7 and buck8 wrong voltages
arm64: tegra: Update Jetson TX1 GPU regulator timings
iwlwifi: pcie: don't service an interrupt that was masked
tracing/snapshot: Resize spare buffer if size changed
NFSv4: Handle the special Linux file open access mode
lib/scatterlist: Fix mapping iterator when sg->offset is greater than PAGE_SIZE
ALSA: seq: Break too long mutex context in the write loop
ALSA: hda/realtek: apply ALC891 headset fixup to one Dell machine
media: v4l2: Test type instead of cfg->type in v4l2_ctrl_new_custom()
media: coda: Remove unbalanced and unneeded mutex unlock
KVM: x86/vPMU: refine kvm_pmu err msg when event creation failed
arm64: tegra: Fix AGIC register range
fs/proc/proc_sysctl.c: fix the default values of i_uid/i_gid on /proc/sys inodes.
drm/nouveau/i2c: Enable i2c pads & busses during preinit
padata: use smp_mb in padata_reorder to avoid orphaned padata jobs
9p/virtio: Add cleanup path in p9_virtio_init
PCI: Do not poll for PME if the device is in D3cold
Btrfs: add missing inode version, ctime and mtime updates when punching hole
libnvdimm/pfn: fix fsdax-mode namespace info-block zero-fields
take floppy compat ioctls to sodding floppy.c
floppy: fix div-by-zero in setup_format_params
floppy: fix out-of-bounds read in next_valid_format
floppy: fix invalid pointer dereference in drive_name
floppy: fix out-of-bounds read in copy_buffer
coda: pass the host file in vma->vm_file on mmap
gpu: ipu-v3: ipu-ic: Fix saturation bit offset in TPMEM
crypto: ccp - Validate the the error value used to index error messages
PCI: hv: Delete the device earlier from hbus->children for hot-remove
PCI: hv: Fix a use-after-free bug in hv_eject_device_work()
crypto: caam - limit output IV to CBC to work around CTR mode DMA issue
um: Allow building and running on older hosts
um: Fix FP register size for XSTATE/XSAVE
parisc: Ensure userspace privilege for ptraced processes in regset functions
parisc: Fix kernel panic due invalid values in IAOQ0 or IAOQ1
powerpc/32s: fix suspend/resume when IBATs 4-7 are used
powerpc/watchpoint: Restore NV GPRs while returning from exception
eCryptfs: fix a couple type promotion bugs
intel_th: msu: Fix single mode with disabled IOMMU
Bluetooth: Add SMP workaround Microsoft Surface Precision Mouse bug
usb: Handle USB3 remote wakeup for LPM enabled devices correctly
dm bufio: fix deadlock with loop device
compiler.h, kasan: Avoid duplicating __read_once_size_nocheck()
compiler.h: Add read_word_at_a_time() function.
lib/strscpy: Shut up KASAN false-positives in strscpy()
ext4: allow directory holes
bnx2x: Prevent load reordering in tx completion processing
bnx2x: Prevent ptp_task to be rescheduled indefinitely
caif-hsi: fix possible deadlock in cfhsi_exit_module()
igmp: fix memory leak in igmpv3_del_delrec()
ipv4: don't set IPv6 only flags to IPv4 addresses
net: bcmgenet: use promisc for unsupported filters
net: dsa: mv88e6xxx: wait after reset deactivation
net: neigh: fix multiple neigh timer scheduling
net: openvswitch: fix csum updates for MPLS actions
nfc: fix potential illegal memory access
rxrpc: Fix send on a connected, but unbound socket
sky2: Disable MSI on ASUS P6T
vrf: make sure skb->data contains ip header to make routing
macsec: fix use-after-free of skb during RX
macsec: fix checksumming after decryption
netrom: fix a memory leak in nr_rx_frame()
netrom: hold sock when setting skb->destructor
bonding: validate ip header before check IPPROTO_IGMP
tcp: Reset bytes_acked and bytes_received when disconnecting
net: bridge: mcast: fix stale nsrcs pointer in igmp3/mld2 report handling
net: bridge: mcast: fix stale ipv6 hdr pointer when handling v6 query
net: bridge: stp: don't cache eth dest pointer before skb pull
perf/x86/amd/uncore: Rename 'L2' to 'LLC'
perf/x86/amd/uncore: Get correct number of cores sharing last level cache
perf/events/amd/uncore: Fix amd_uncore_llc ID to use pre-defined cpu_llc_id
NFSv4: Fix open create exclusive when the server reboots
nfsd: increase DRC cache limit
nfsd: give out fewer session slots as limit approaches
nfsd: fix performance-limiting session calculation
nfsd: Fix overflow causing non-working mounts on 1 TB machines
drm/panel: simple: Fix panel_simple_dsi_probe
usb: core: hub: Disable hub-initiated U1/U2
tty: max310x: Fix invalid baudrate divisors calculator
pinctrl: rockchip: fix leaked of_node references
tty: serial: cpm_uart - fix init when SMC is relocated
drm/bridge: tc358767: read display_props in get_modes()
drm/bridge: sii902x: pixel clock unit is 10kHz instead of 1kHz
memstick: Fix error cleanup path of memstick_init
tty/serial: digicolor: Fix digicolor-usart already registered warning
tty: serial: msm_serial: avoid system lockup condition
serial: 8250: Fix TX interrupt handling condition
drm/virtio: Add memory barriers for capset cache.
phy: renesas: rcar-gen2: Fix memory leak at error paths
drm/rockchip: Properly adjust to a true clock in adjusted_mode
tty: serial_core: Set port active bit in uart_port_activate
usb: gadget: Zero ffs_io_data
powerpc/pci/of: Fix OF flags parsing for 64bit BARs
PCI: sysfs: Ignore lockdep for remove attribute
kbuild: Add -Werror=unknown-warning-option to CLANG_FLAGS
PCI: xilinx-nwl: Fix Multi MSI data programming
iio: iio-utils: Fix possible incorrect mask calculation
recordmcount: Fix spurious mcount entries on powerpc
mfd: core: Set fwnode for created devices
mfd: arizona: Fix undefined behavior
mfd: hi655x-pmic: Fix missing return value check for devm_regmap_init_mmio_clk
um: Silence lockdep complaint about mmap_sem
powerpc/4xx/uic: clear pending interrupt after irq type/pol change
RDMA/i40iw: Set queue pair state when being queried
serial: sh-sci: Terminate TX DMA during buffer flushing
serial: sh-sci: Fix TX DMA buffer flushing and workqueue races
kallsyms: exclude kasan local symbols on s390
perf test mmap-thread-lookup: Initialize variable to suppress memory sanitizer warning
RDMA/rxe: Fill in wc byte_len with IB_WC_RECV_RDMA_WITH_IMM
powerpc/boot: add {get, put}_unaligned_be32 to xz_config.h
f2fs: avoid out-of-range memory access
mailbox: handle failed named mailbox channel request
powerpc/eeh: Handle hugepages in ioremap space
sh: prevent warnings when using iounmap
mm/kmemleak.c: fix check for softirq context
9p: pass the correct prototype to read_cache_page
mm/mmu_notifier: use hlist_add_head_rcu()
locking/lockdep: Fix lock used or unused stats error
locking/lockdep: Hide unused 'class' variable
usb: wusbcore: fix unbalanced get/put cluster_id
usb: pci-quirks: Correct AMD PLL quirk detection
x86/sysfb_efi: Add quirks for some devices with swapped width and height
x86/speculation/mds: Apply more accurate check on hypervisor platform
hpet: Fix division by zero in hpet_time_div()
ALSA: line6: Fix wrong altsetting for LINE6_PODHD500_1
ALSA: hda - Add a conexant codec entry to let mute led work
powerpc/tm: Fix oops on sigreturn on systems without TM
access: avoid the RCU grace period for the temporary subjective credentials
ipv6: check sk sk_type and protocol early in ip_mroute_set/getsockopt
tcp: reset sk_send_head in tcp_write_queue_purge
arm64: dts: marvell: Fix A37xx UART0 register size
i2c: qup: fixed releasing dma without flush operation completion
arm64: compat: Provide definition for COMPAT_SIGMINSTKSZ
ISDN: hfcsusb: checking idx of ep configuration
media: au0828: fix null dereference in error path
media: cpia2_usb: first wake up, then free in disconnect
media: radio-raremono: change devm_k*alloc to k*alloc
Bluetooth: hci_uart: check for missing tty operations
sched/fair: Don't free p->numa_faults with concurrent readers
drivers/pps/pps.c: clear offset flags in PPS_SETPARAMS ioctl
ceph: hold i_ceph_lock when removing caps for freeing inode
Linux 4.9.187
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
commit 16d51a590a8ce3befb1308e0e7ab77f3b661af33 upstream.
When going through execve(), zero out the NUMA fault statistics instead of
freeing them.
During execve, the task is reachable through procfs and the scheduler. A
concurrent /proc/*/sched reader can read data from a freed ->numa_faults
allocation (confirmed by KASAN) and write it back to userspace.
I believe that it would also be possible for a use-after-free read to occur
through a race between a NUMA fault and execve(): task_numa_fault() can
lead to task_numa_compare(), which invokes task_weight() on the currently
running task of a different CPU.
Another way to fix this would be to make ->numa_faults RCU-managed or add
extra locking, but it seems easier to wipe the NUMA fault statistics on
execve.
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Fixes: 82727018b0 ("sched/numa: Call task_numa_free() from do_execve()")
Link: https://lkml.kernel.org/r/20190716152047.14424-1-jannh@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When systems are overcommitted and resources become contended, it's hard
to tell exactly the impact this has on workload productivity, or how close
the system is to lockups and OOM kills. In particular, when machines work
multiple jobs concurrently, the impact of overcommit in terms of latency
and throughput on the individual job can be enormous.
In order to maximize hardware utilization without sacrificing individual
job health or risk complete machine lockups, this patch implements a way
to quantify resource pressure in the system.
A kernel built with CONFIG_PSI=y creates files in /proc/pressure/ that
expose the percentage of time the system is stalled on CPU, memory, or IO,
respectively. Stall states are aggregate versions of the per-task delay
accounting delays:
cpu: some tasks are runnable but not executing on a CPU
memory: tasks are reclaiming, or waiting for swapin or thrashing cache
io: tasks are waiting for io completions
These percentages of walltime can be thought of as pressure percentages,
and they give a general sense of system health and productivity loss
incurred by resource overcommit. They can also indicate when the system
is approaching lockup scenarios and OOMs.
To do this, psi keeps track of the task states associated with each CPU
and samples the time they spend in stall states. Every 2 seconds, the
samples are averaged across CPUs - weighted by the CPUs' non-idle time to
eliminate artifacts from unused CPUs - and translated into percentages of
walltime. A running average of those percentages is maintained over 10s,
1m, and 5m periods (similar to the loadaverage).
[hannes@cmpxchg.org: doc fixlet, per Randy]
Link: http://lkml.kernel.org/r/20180828205625.GA14030@cmpxchg.org
[hannes@cmpxchg.org: code optimization]
Link: http://lkml.kernel.org/r/20180907175015.GA8479@cmpxchg.org
[hannes@cmpxchg.org: rename psi_clock() to psi_update_work(), per Peter]
Link: http://lkml.kernel.org/r/20180907145404.GB11088@cmpxchg.org
[hannes@cmpxchg.org: fix build]
Link: http://lkml.kernel.org/r/20180913014222.GA2370@cmpxchg.org
Link: http://lkml.kernel.org/r/20180828172258.3185-9-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Daniel Drake <drake@endlessm.com>
Tested-by: Suren Baghdasaryan <surenb@google.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <jweiner@fb.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Enderborg <peter.enderborg@sony.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit eb414681d5a07d28d2ff90dc05f69ec6b232ebd2)
Bug: 111308141
Test: modified lmkd to use PSI and tested using lmkd_unit_test
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: I54a65620b3ed6f8172fdec789a237a99f8c82156
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Merge 4.9.150 into android-4.9
Changes in 4.9.150
pinctrl: meson: fix pull enable register calculation
powerpc: Fix COFF zImage booting on old powermacs
ARM: imx: update the cpu power up timing setting on i.mx6sx
ARM: dts: imx7d-nitrogen7: Fix the description of the Wifi clock
Input: restore EV_ABS ABS_RESERVED
checkstack.pl: fix for aarch64
xfrm: Fix bucket count reported to userspace
netfilter: seqadj: re-load tcp header pointer after possible head reallocation
scsi: bnx2fc: Fix NULL dereference in error handling
Input: omap-keypad - fix idle configuration to not block SoC idle states
netfilter: ipset: do not call ipset_nest_end after nla_nest_cancel
bnx2x: Clear fip MAC when fcoe offload support is disabled
bnx2x: Remove configured vlans as part of unload sequence.
bnx2x: Send update-svid ramrod with retry/poll flags enabled
scsi: target: iscsi: cxgbit: fix csk leak
scsi: target: iscsi: cxgbit: add missing spin_lock_init()
drivers: net: xgene: Remove unnecessary forward declarations
w90p910_ether: remove incorrect __init annotation
net: hns: Incorrect offset address used for some registers.
net: hns: All ports can not work when insmod hns ko after rmmod.
net: hns: Some registers use wrong address according to the datasheet.
net: hns: Fixed bug that netdev was opened twice
net: hns: Clean rx fbd when ae stopped.
net: hns: Free irq when exit from abnormal branch
net: hns: Avoid net reset caused by pause frames storm
net: hns: Fix ntuple-filters status error.
net: hns: Add mac pcs config when enable|disable mac
SUNRPC: Fix a race with XPRT_CONNECTING
lan78xx: Resolve issue with changing MAC address
vxge: ensure data0 is initialized in when fetching firmware version information
net: netxen: fix a missing check and an uninitialized use
serial/sunsu: fix refcount leak
scsi: zfcp: fix posting too many status read buffers leading to adapter shutdown
libceph: fix CEPH_FEATURE_CEPHX_V2 check in calc_signature()
fork: record start_time late
hwpoison, memory_hotplug: allow hwpoisoned pages to be offlined
mm, devm_memremap_pages: mark devm_memremap_pages() EXPORT_SYMBOL_GPL
mm, devm_memremap_pages: kill mapping "System RAM" support
sunrpc: fix cache_head leak due to queued request
sunrpc: use SVC_NET() in svcauth_gss_* functions
MIPS: math-emu: Write-protect delay slot emulation pages
crypto: x86/chacha20 - avoid sleeping with preemption disabled
vhost/vsock: fix uninitialized vhost_vsock->guest_cid
IB/hfi1: Incorrect sizing of sge for PIO will OOPs
ALSA: cs46xx: Potential NULL dereference in probe
ALSA: usb-audio: Avoid access before bLength check in build_audio_procunit()
ALSA: usb-audio: Fix an out-of-bound read in create_composite_quirks
dlm: fixed memory leaks after failed ls_remove_names allocation
dlm: possible memory leak on error path in create_lkb()
dlm: lost put_lkb on error path in receive_convert() and receive_unlock()
dlm: memory leaks on error path in dlm_user_request()
gfs2: Get rid of potential double-freeing in gfs2_create_inode
gfs2: Fix loop in gfs2_rbm_find
b43: Fix error in cordic routine
powerpc/tm: Set MSR[TS] just prior to recheckpoint
9p/net: put a lower bound on msize
rxe: fix error completion wr_id and qp_num
iommu/vt-d: Handle domain agaw being less than iommu agaw
ceph: don't update importing cap's mseq when handing cap export
genwqe: Fix size check
intel_th: msu: Fix an off-by-one in attribute store
power: supply: olpc_battery: correct the temperature units
drm/vc4: Set ->is_yuv to false when num_planes == 1
bnx2x: Fix NULL pointer dereference in bnx2x_del_all_vlans() on some hw
Linux 4.9.150
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
commit 7b55851367136b1efd84d98fea81ba57a98304cf upstream.
This changes the fork(2) syscall to record the process start_time after
initializing the basic task structure but still before making the new
process visible to user-space.
Technically, we could record the start_time anytime during fork(2). But
this might lead to scenarios where a start_time is recorded long before
a process becomes visible to user-space. For instance, with
userfaultfd(2) and TLS, user-space can delay the execution of fork(2)
for an indefinite amount of time (and will, if this causes network
access, or similar).
By recording the start_time late, it much closer reflects the point in
time where the process becomes live and can be observed by other
processes.
Lastly, this makes it much harder for user-space to predict and control
the start_time they get assigned. Previously, user-space could fork a
process and stall it in copy_thread_tls() before its pid is allocated,
but after its start_time is recorded. This can be misused to later-on
cycle through PIDs and resume the stalled fork(2) yielding a process
that has the same pid and start_time as a process that existed before.
This can be used to circumvent security systems that identify processes
by their pid+start_time combination.
Even though user-space was always aware that start_time recording is
flaky (but several projects are known to still rely on start_time-based
identification), changing the start_time to be recorded late will help
mitigate existing attacks and make it much harder for user-space to
control the start_time a process gets assigned.
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Tom Gundersen <teg@jklm.no>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge 4.9.128 into android-4.9
Changes in 4.9.128
i2c: xiic: Make the start and the byte count write atomic
i2c: i801: fix DNV's SMBCTRL register offset
KVM: s390: vsie: copy wrapping keys to right place
ALSA: hda - Fix cancel_work_sync() stall from jackpoll work
cfq: Give a chance for arming slice idle timer in case of group_idle
kthread: Fix use-after-free if kthread fork fails
kthread: fix boot hang (regression) on MIPS/OpenRISC
staging: rt5208: Fix a sleep-in-atomic bug in xd_copy_page
staging/rts5208: Fix read overflow in memcpy
IB/rxe: do not copy extra stack memory to skb
block,blkcg: use __GFP_NOWARN for best-effort allocations in blkcg
nl80211: fix null-ptr dereference on invalid mesh configuration
locking/rwsem-xadd: Fix missed wakeup due to reordering of load
selinux: use GFP_NOWAIT in the AVC kmem_caches
locking/osq_lock: Fix osq_lock queue corruption
mm, vmscan: clear PGDAT_WRITEBACK when zone is balanced
mm: remove seemingly spurious reclaimability check from laptop_mode gating
ARC: [plat-axs*]: Enable SWAP
misc: mic: SCIF Fix scif_get_new_port() error handling
ethtool: Remove trailing semicolon for static inline
Bluetooth: h5: Fix missing dependency on BT_HCIUART_SERDEV
gpio: tegra: Move driver registration to subsys_init level
net: phy: Fix the register offsets in Broadcom iProc mdio mux driver
scsi: target: fix __transport_register_session locking
md/raid5: fix data corruption of replacements after originals dropped
timers: Clear timer_base::must_forward_clk with timer_base::lock held
misc: ti-st: Fix memory leak in the error path of probe()
uio: potential double frees if __uio_register_device() fails
tty: rocket: Fix possible buffer overwrite on register_PCI
f2fs: do not set free of current section
perf tools: Allow overriding MAX_NR_CPUS at compile time
NFSv4.0 fix client reference leak in callback
macintosh/via-pmu: Add missing mmio accessors
ath9k: report tx status on EOSP
ath9k_hw: fix channel maximum power level test
ath10k: prevent active scans on potential unusable channels
wlcore: Set rx_status boottime_ns field on rx
MIPS: Fix ISA virt/bus conversion for non-zero PHYS_OFFSET
ata: libahci: Correct setting of DEVSLP register
scsi: 3ware: fix return 0 on the error path of probe
ath10k: disable bundle mgmt tx completion event support
Bluetooth: hidp: Fix handling of strncpy for hid->name information
x86/mm: Remove in_nmi() warning from vmalloc_fault()
gpio: ml-ioh: Fix buffer underwrite on probe error path
net: mvneta: fix mtu change on port without link
f2fs: try grabbing node page lock aggressively in sync scenario
f2fs: fix to skip GC if type in SSA and SIT is inconsistent
tpm_tis_spi: Pass the SPI IRQ down to the driver
tpm/tpm_i2c_infineon: switch to i2c_lock_bus(..., I2C_LOCK_SEGMENT)
f2fs: fix to do sanity check with reserved blkaddr of inline inode
MIPS: Octeon: add missing of_node_put()
MIPS: generic: fix missing of_node_put()
net: dcb: For wild-card lookups, use priority -1, not 0
Input: atmel_mxt_ts - only use first T9 instance
media: s5p-mfc: Fix buffer look up in s5p_mfc_handle_frame_{new, copy_time} functions
partitions/aix: append null character to print data from disk
partitions/aix: fix usage of uninitialized lv_info and lvname structures
media: helene: fix xtal frequency setting at power on
f2fs: Fix uninitialized return in f2fs_ioc_shutdown()
iommu/ipmmu-vmsa: Fix allocation in atomic context
mfd: ti_am335x_tscadc: Fix struct clk memory leak
f2fs: fix to do sanity check with {sit,nat}_ver_bitmap_bytesize
NFSv4.1: Fix a potential layoutget/layoutrecall deadlock
MIPS: WARN_ON invalid DMA cache maintenance, not BUG_ON
RDMA/cma: Do not ignore net namespace for unbound cm_id
xhci: Fix use-after-free in xhci_free_virt_device
netfilter: x_tables: avoid stack-out-of-bounds read in xt_copy_counters_from_user
mtd: ubi: wl: Fix error return code in ubi_wl_init()
autofs: fix autofs_sbi() does not check super block type
mm: get rid of vmacache_flush_all() entirely
Linux 4.9.128
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
commit 4d6501dce079c1eb6bf0b1d8f528a5e81770109e upstream.
If a kthread forks (e.g. usermodehelper since commit 1da5c46fa965) but
fails in copy_process() between calling dup_task_struct() and setting
p->set_child_tid, then the value of p->set_child_tid will be inherited
from the parent and get prematurely freed by free_kthread_struct().
kthread()
- worker_thread()
- process_one_work()
| - call_usermodehelper_exec_work()
| - kernel_thread()
| - _do_fork()
| - copy_process()
| - dup_task_struct()
| - arch_dup_task_struct()
| - tsk->set_child_tid = current->set_child_tid // implied
| - ...
| - goto bad_fork_*
| - ...
| - free_task(tsk)
| - free_kthread_struct(tsk)
| - kfree(tsk->set_child_tid)
- ...
- schedule()
- __schedule()
- wq_worker_sleeping()
- kthread_data(task)->flags // UAF
The problem started showing up with commit 1da5c46fa965 since it reused
->set_child_tid for the kthread worker data.
A better long-term solution might be to get rid of the ->set_child_tid
abuse. The comment in set_kthread_struct() also looks slightly wrong.
Debugged-by: Jamie Iles <jamie.iles@oracle.com>
Fixes: 1da5c46fa965 ("kthread: Make struct kthread kmalloc'ed")
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jamie Iles <jamie.iles@oracle.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20170509073959.17858-1-vegard.nossum@oracle.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge 4.9.127 into android-4.9
Changes in 4.9.127
x86/speculation/l1tf: Fix up pte->pfn conversion for PAE
act_ife: fix a potential use-after-free
ipv4: tcp: send zero IPID for RST and ACK sent in SYN-RECV and TIME-WAIT state
net: bcmgenet: use MAC link status for fixed phy
net: sched: Fix memory exposure from short TCA_U32_SEL
qlge: Fix netdev features configuration.
r8169: add support for NCube 8168 network card
tcp: do not restart timewait timer on rst reception
vti6: remove !skb->ignore_df check from vti6_xmit()
sctp: hold transport before accessing its asoc in sctp_transport_get_next
vhost: correctly check the iova range when waking virtqueue
hv_netvsc: ignore devices that are not PCI
act_ife: move tcfa_lock down to where necessary
act_ife: fix a potential deadlock
net: sched: action_ife: take reference to meta module
cifs: check if SMB2 PDU size has been padded and suppress the warning
hfsplus: don't return 0 when fill_super() failed
hfs: prevent crash on exit from failed search
sunrpc: Don't use stack buffer with scatterlist
fork: don't copy inconsistent signal handler state to child
reiserfs: change j_timestamp type to time64_t
hfsplus: fix NULL dereference in hfsplus_lookup()
fat: validate ->i_start before using
scripts: modpost: check memory allocation results
virtio: pci-legacy: Validate queue pfn
mm/fadvise.c: fix signed overflow UBSAN complaint
fs/dcache.c: fix kmemcheck splat at take_dentry_name_snapshot()
platform/x86: intel_punit_ipc: fix build errors
s390/kdump: Fix memleak in nt_vmcoreinfo
ipvs: fix race between ip_vs_conn_new() and ip_vs_del_dest()
mfd: sm501: Set coherent_dma_mask when creating subdevices
platform/x86: asus-nb-wmi: Add keymap entry for lid flip action on UX360
RDMA/hns: Fix usage of bitmap allocation functions return values
irqchip/bcm7038-l1: Hide cpu offline callback when building for !SMP
net/9p/trans_fd.c: fix race by holding the lock
net/9p: fix error path of p9_virtio_probe
powerpc: Fix size calculation using resource_size()
perf probe powerpc: Fix trace event post-processing
block: bvec_nr_vecs() returns value for wrong slab
s390/dasd: fix hanging offline processing due to canceled worker
s390/dasd: fix panic for failed online processing
ACPI / scan: Initialize status to ACPI_STA_DEFAULT
scsi: aic94xx: fix an error code in aic94xx_init()
PCI: mvebu: Fix I/O space end address calculation
dm kcopyd: avoid softlockup in run_complete_job
staging: comedi: ni_mio_common: fix subdevice flags for PFI subdevice
selftests/powerpc: Kill child processes on SIGINT
RDS: IB: fix 'passing zero to ERR_PTR()' warning
smb3: fix reset of bytes read and written stats
SMB3: Number of requests sent should be displayed for SMB3 not just CIFS
powerpc/pseries: Avoid using the size greater than RTAS_ERROR_LOG_MAX.
clk: rockchip: Add pclk_rkpwm_pmu to PMU critical clocks in rk3399
btrfs: replace: Reset on-disk dev stats value after replace
btrfs: relocation: Only remove reloc rb_trees if reloc control has been initialized
btrfs: Don't remove block group that still has pinned down bytes
arm64: rockchip: Force CONFIG_PM on Rockchip systems
ARM: rockchip: Force CONFIG_PM on Rockchip systems
drm/edid: Add 6 bpc quirk for SDC panel in Lenovo B50-80
tcp: Revert "tcp: tcp_probe: use spin_lock_bh()"
debugobjects: Make stack check warning more informative
x86/pae: use 64 bit atomic xchg function in native_ptep_get_and_clear
kbuild: make missing $DEPMOD a Warning instead of an Error
irda: Fix memory leak caused by repeated binds of irda socket
irda: Only insert new objects into the global database via setsockopt
Revert "ARM: imx_v6_v7_defconfig: Select ULPI support"
enic: do not call enic_change_mtu in enic_probe
Fixes: Commit 2aa6d036b7 ("mm: numa: avoid waiting on freed migrated pages")
sch_htb: fix crash on init failure
sch_multiq: fix double free on init failure
sch_hhf: fix null pointer dereference on init failure
sch_netem: avoid null pointer deref on init failure
sch_tbf: fix two null pointer dereferences on init failure
mei: me: allow runtime pm for platform with D0i3
s390/lib: use expoline for all bcr instructions
ASoC: wm8994: Fix missing break in switch
btrfs: use correct compare function of dirty_metadata_bytes
arm64: Fix mismatched cache line size detection
arm64: Handle mismatched cache type
Linux 4.9.127
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
[ Upstream commit 06e62a46bbba20aa5286102016a04214bb446141 ]
Before this change, if a multithreaded process forks while one of its
threads is changing a signal handler using sigaction(), the memcpy() in
copy_sighand() can race with the struct assignment in do_sigaction(). It
isn't clear whether this can cause corruption of the userspace signal
handler pointer, but it definitely can cause inconsistency between
different fields of struct sigaction.
Take the appropriate spinlock to avoid this.
I have tested that this patch prevents inconsistency between sa_sigaction
and sa_flags, which is possible before this patch.
Link: http://lkml.kernel.org/r/20180702145108.73189-1-jannh@google.com
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge 4.9.119 into android-4.9
Changes in 4.9.119
scsi: qla2xxx: Fix ISP recovery on unload
scsi: qla2xxx: Return error when TMF returns
genirq: Make force irq threading setup more robust
nohz: Fix local_timer_softirq_pending()
netlink: Do not subscribe to non-existent groups
netlink: Don't shift with UB on nlk->ngroups
netlink: Don't shift on 64 for ngroups
ext4: fix false negatives *and* false positives in ext4_check_descriptors()
ACPI / PCI: Bail early in acpi_pci_add_bus() if there is no ACPI handle
ring_buffer: tracing: Inherit the tracing setting to next ring buffer
i2c: imx: Fix reinit_completion() use
Btrfs: fix file data corruption after cloning a range and fsync
tcp: add tcp_ooo_try_coalesce() helper
kmemleak: clear stale pointers from task stacks
fork: unconditionally clear stack on fork
IB/hfi1: Fix incorrect mixing of ERR_PTR and NULL return values
jfs: Fix inconsistency between memory allocation and ea_buf->max_size
Linux 4.9.119
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
commit e01e80634ecdde1dd113ac43b3adad21b47f3957 upstream.
One of the classes of kernel stack content leaks[1] is exposing the
contents of prior heap or stack contents when a new process stack is
allocated. Normally, those stacks are not zeroed, and the old contents
remain in place. In the face of stack content exposure flaws, those
contents can leak to userspace.
Fixing this will make the kernel no longer vulnerable to these flaws, as
the stack will be wiped each time a stack is assigned to a new process.
There's not a meaningful change in runtime performance; it almost looks
like it provides a benefit.
Performing back-to-back kernel builds before:
Run times: 157.86 157.09 158.90 160.94 160.80
Mean: 159.12
Std Dev: 1.54
and after:
Run times: 159.31 157.34 156.71 158.15 160.81
Mean: 158.46
Std Dev: 1.46
Instead of making this a build or runtime config, Andy Lutomirski
recommended this just be enabled by default.
[1] A noisy search for many kinds of stack content leaks can be seen here:
https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=linux+kernel+stack+leak
I did some more with perf and cycle counts on running 100,000 execs of
/bin/true.
before:
Cycles: 218858861551 218853036130 214727610969 227656844122 224980542841
Mean: 221015379122.60
Std Dev: 4662486552.47
after:
Cycles: 213868945060 213119275204 211820169456 224426673259 225489986348
Mean: 217745009865.40
Std Dev: 5935559279.99
It continues to look like it's faster, though the deviation is rather
wide, but I'm not sure what I could do that would be less noisy. I'm
open to ideas!
Link: http://lkml.kernel.org/r/20180221021659.GA37073@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ Srivatsa: Backported to 4.9.y ]
Signed-off-by: Srivatsa S. Bhat <srivatsa@csail.mit.edu>
Reviewed-by: Srinidhi Rao <srinidhir@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Every time _cpu_up() is called for a CPU, idle_thread_get() is called
which then re-initializes a CPU's idle thread that was already
previously created and cached in a global variable in
smpboot.c. idle_thread_get() calls init_idle() which then calls
__sched_fork(). __sched_fork() is where cpufreq_task_times_init() is,
and cpufreq_task_times_init() allocates memory for the task struct's
time_in_state array.
Since idle_thread_get() reuses a task struct instance that was already
previously created, this means that every time it calls init_idle(),
cpufreq_task_times_init() allocates this array again and overwrites
the existing allocation that the idle thread already had.
This causes memory to be leaked every time a CPU is onlined. In order
to fix this, move allocation of time_in_state into _do_fork to avoid
allocating it at all for idle threads. The cpufreq times interface is
intended to be used for tracking userspace tasks, so we can safely
remove it from the kernel's idle threads without killing any
functionality.
But that's not all!
Task structs can be freed outside of release_task(), which creates
another memory leak because a task struct can be freed without having
its cpufreq times allocation freed. To fix this, free the cpufreq
times allocation at the same time that task struct allocations are
freed, in free_task().
Since free_task() can also be called in error paths of copy_process()
after dup_task_struct(), set time_in_state to NULL immediately after
calling dup_task_struct() to avoid possible double free.
Bug description and fix adapted from patch submitted by
Sultan Alsawaf <sultanxda@gmail.com> at
https://android-review.googlesource.com/c/kernel/msm/+/700134
Bug: 110044919
Test: Hikey960 builds, boots & reports /proc/<pid>/time_in_state
correctly
Change-Id: I12fe7611fc88eb7f6c39f8f7629ad27b6ec4722c
Signed-off-by: Connor O'Brien <connoro@google.com>
Kaiser only needs to map one page of the stack; and
kernel/fork.c did not build on powerpc (no __PAGE_KERNEL).
It's all cleaner if linux/kaiser.h provides kaiser_map_thread_stack()
and kaiser_unmap_thread_stack() wrappers around asm/kaiser.h's
kaiser_add_mapping() and kaiser_remove_mapping(). And use
linux/kaiser.h in init/main.c to avoid the #ifdefs there.
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merged fixes and cleanups, rebased to 4.9.51 tree (no 5-level paging).
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch introduces our implementation of KAISER (Kernel Address Isolation to
have Side-channels Efficiently Removed), a kernel isolation technique to close
hardware side channels on kernel address information.
More information about the patch can be found on:
https://github.com/IAIK/KAISER
From: Richard Fellner <richard.fellner@student.tugraz.at>
From: Daniel Gruss <daniel.gruss@iaik.tugraz.at>
Subject: [RFC, PATCH] x86_64: KAISER - do not map kernel in user mode
Date: Thu, 4 May 2017 14:26:50 +0200
Link: http://marc.info/?l=linux-kernel&m=149390087310405&w=2
Kaiser-4.10-SHA1: c4b1831d44c6144d3762ccc72f0c4e71a0c713e5
To: <linux-kernel@vger.kernel.org>
To: <kernel-hardening@lists.openwall.com>
Cc: <clementine.maurice@iaik.tugraz.at>
Cc: <moritz.lipp@iaik.tugraz.at>
Cc: Michael Schwarz <michael.schwarz@iaik.tugraz.at>
Cc: Richard Fellner <richard.fellner@student.tugraz.at>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: <kirill.shutemov@linux.intel.com>
Cc: <anders.fogh@gdata-adan.de>
After several recent works [1,2,3] KASLR on x86_64 was basically
considered dead by many researchers. We have been working on an
efficient but effective fix for this problem and found that not mapping
the kernel space when running in user mode is the solution to this
problem [4] (the corresponding paper [5] will be presented at ESSoS17).
With this RFC patch we allow anybody to configure their kernel with the
flag CONFIG_KAISER to add our defense mechanism.
If there are any questions we would love to answer them.
We also appreciate any comments!
Cheers,
Daniel (+ the KAISER team from Graz University of Technology)
[1] 4977a191.pdf
[2] https://www.blackhat.com/docs/us-16/materials/us-16-Fogh-Using-Undocumented-CPU-Behaviour-To-See-Into-Kernel-Mode-And-Break-KASLR-In-The-Process.pdf
[3] https://www.blackhat.com/docs/us-16/materials/us-16-Jang-Breaking-Kernel-Address-Space-Layout-Randomization-KASLR-With-Intel-TSX.pdf
[4] https://github.com/IAIK/KAISER
[5] https://gruss.cc/files/kaiser.pdf
[patch based also on
https://raw.githubusercontent.com/IAIK/KAISER/master/KAISER/0001-KAISER-Kernel-Address-Isolation.patch]
Signed-off-by: Richard Fellner <richard.fellner@student.tugraz.at>
Signed-off-by: Moritz Lipp <moritz.lipp@iaik.tugraz.at>
Signed-off-by: Daniel Gruss <daniel.gruss@iaik.tugraz.at>
Signed-off-by: Michael Schwarz <michael.schwarz@iaik.tugraz.at>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 355627f518978b5167256d27492fe0b343aaf2f2 upstream.
Commit 7c05126793 ("mm, fork: make dup_mmap wait for mmap_sem for
write killable") made it possible to kill a forking task while it is
waiting to acquire its ->mmap_sem for write, in dup_mmap().
However, it was overlooked that this introduced an new error path before
the new mm_struct's ->uprobes_state.xol_area has been set to NULL after
being copied from the old mm_struct by the memcpy in dup_mm(). For a
task that has previously hit a uprobe tracepoint, this resulted in the
'struct xol_area' being freed multiple times if the task was killed at
just the right time while forking.
Fix it by setting ->uprobes_state.xol_area to NULL in mm_init() rather
than in uprobe_dup_mmap().
With CONFIG_UPROBE_EVENTS=y, the bug can be reproduced by the same C
program given by commit 2b7e8665b4ff ("fork: fix incorrect fput of
->exe_file causing use-after-free"), provided that a uprobe tracepoint
has been set on the fork_thread() function. For example:
$ gcc reproducer.c -o reproducer -lpthread
$ nm reproducer | grep fork_thread
0000000000400719 t fork_thread
$ echo "p $PWD/reproducer:0x719" > /sys/kernel/debug/tracing/uprobe_events
$ echo 1 > /sys/kernel/debug/tracing/events/uprobes/enable
$ ./reproducer
Here is the use-after-free reported by KASAN:
BUG: KASAN: use-after-free in uprobe_clear_state+0x1c4/0x200
Read of size 8 at addr ffff8800320a8b88 by task reproducer/198
CPU: 1 PID: 198 Comm: reproducer Not tainted 4.13.0-rc7-00015-g36fde05f3fb5 #255
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014
Call Trace:
dump_stack+0xdb/0x185
print_address_description+0x7e/0x290
kasan_report+0x23b/0x350
__asan_report_load8_noabort+0x19/0x20
uprobe_clear_state+0x1c4/0x200
mmput+0xd6/0x360
do_exit+0x740/0x1670
do_group_exit+0x13f/0x380
get_signal+0x597/0x17d0
do_signal+0x99/0x1df0
exit_to_usermode_loop+0x166/0x1e0
syscall_return_slowpath+0x258/0x2c0
entry_SYSCALL_64_fastpath+0xbc/0xbe
...
Allocated by task 199:
save_stack_trace+0x1b/0x20
kasan_kmalloc+0xfc/0x180
kmem_cache_alloc_trace+0xf3/0x330
__create_xol_area+0x10f/0x780
uprobe_notify_resume+0x1674/0x2210
exit_to_usermode_loop+0x150/0x1e0
prepare_exit_to_usermode+0x14b/0x180
retint_user+0x8/0x20
Freed by task 199:
save_stack_trace+0x1b/0x20
kasan_slab_free+0xa8/0x1a0
kfree+0xba/0x210
uprobe_clear_state+0x151/0x200
mmput+0xd6/0x360
copy_process.part.8+0x605f/0x65d0
_do_fork+0x1a5/0xbd0
SyS_clone+0x19/0x20
do_syscall_64+0x22f/0x660
return_from_SYSCALL_64+0x0/0x7a
Note: without KASAN, you may instead see a "Bad page state" message, or
simply a general protection fault.
Link: http://lkml.kernel.org/r/20170830033303.17927-1-ebiggers3@gmail.com
Fixes: 7c05126793 ("mm, fork: make dup_mmap wait for mmap_sem for write killable")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2b7e8665b4ff51c034c55df3cff76518d1a9ee3a upstream.
Commit 7c05126793 ("mm, fork: make dup_mmap wait for mmap_sem for
write killable") made it possible to kill a forking task while it is
waiting to acquire its ->mmap_sem for write, in dup_mmap().
However, it was overlooked that this introduced an new error path before
a reference is taken on the mm_struct's ->exe_file. Since the
->exe_file of the new mm_struct was already set to the old ->exe_file by
the memcpy() in dup_mm(), it was possible for the mmput() in the error
path of dup_mm() to drop a reference to ->exe_file which was never
taken.
This caused the struct file to later be freed prematurely.
Fix it by updating mm_init() to NULL out the ->exe_file, in the same
place it clears other things like the list of mmaps.
This bug was found by syzkaller. It can be reproduced using the
following C program:
#define _GNU_SOURCE
#include <pthread.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#include <sys/wait.h>
#include <unistd.h>
static void *mmap_thread(void *_arg)
{
for (;;) {
mmap(NULL, 0x1000000, PROT_READ,
MAP_POPULATE|MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
}
}
static void *fork_thread(void *_arg)
{
usleep(rand() % 10000);
fork();
}
int main(void)
{
fork();
fork();
fork();
for (;;) {
if (fork() == 0) {
pthread_t t;
pthread_create(&t, NULL, mmap_thread, NULL);
pthread_create(&t, NULL, fork_thread, NULL);
usleep(rand() % 10000);
syscall(__NR_exit_group, 0);
}
wait(NULL);
}
}
No special kernel config options are needed. It usually causes a NULL
pointer dereference in __remove_shared_vm_struct() during exit, or in
dup_mmap() (which is usually inlined into copy_process()) during fork.
Both are due to a vm_area_struct's ->vm_file being used after it's
already been freed.
Google Bug Id: 64772007
Link: http://lkml.kernel.org/r/20170823211408.31198-1-ebiggers3@gmail.com
Fixes: 7c05126793 ("mm, fork: make dup_mmap wait for mmap_sem for write killable")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5ea30e4e58040cfd6434c2f33dc3ea76e2c15b05 upstream.
The stack canary is an 'unsigned long' and should be fully initialized to
random data rather than only 32 bits of random data.
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Arjan van Ven <arjan@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-hardening@lists.openwall.com
Link: http://lkml.kernel.org/r/20170504133209.3053-1-danielmicay@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3fd37226216620c1a468afa999739d5016fbc349 upstream.
Imagine we have a pid namespace and a task from its parent's pid_ns,
which made setns() to the pid namespace. The task is doing fork(),
while the pid namespace's child reaper is dying. We have the race
between them:
Task from parent pid_ns Child reaper
copy_process() ..
alloc_pid() ..
.. zap_pid_ns_processes()
.. disable_pid_allocation()
.. read_lock(&tasklist_lock)
.. iterate over pids in pid_ns
.. kill tasks linked to pids
.. read_unlock(&tasklist_lock)
write_lock_irq(&tasklist_lock); ..
attach_pid(p, PIDTYPE_PID); ..
.. ..
So, just created task p won't receive SIGKILL signal,
and the pid namespace will be in contradictory state.
Only manual kill will help there, but does the userspace
care about this? I suppose, the most users just inject
a task into a pid namespace and wait a SIGCHLD from it.
The patch fixes the problem. It simply checks for
(pid_ns->nr_hashed & PIDNS_HASH_ADDING) in copy_process().
We do it under the tasklist_lock, and can't skip
PIDNS_HASH_ADDING as noted by Oleg:
"zap_pid_ns_processes() does disable_pid_allocation()
and then takes tasklist_lock to kill the whole namespace.
Given that copy_process() checks PIDNS_HASH_ADDING
under write_lock(tasklist) they can't race;
if copy_process() takes this lock first, the new child will
be killed, otherwise copy_process() can't miss
the change in ->nr_hashed."
If allocation is disabled, we just return -ENOMEM
like it's made for such cases in alloc_pid().
v2: Do not move disable_pid_allocation(), do not
introduce a new variable in copy_process() and simplify
the patch as suggested by Oleg Nesterov.
Account the problem with double irq enabling
found by Eric W. Biederman.
Fixes: c876ad7682 ("pidns: Stop pid allocation when init dies")
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Ingo Molnar <mingo@kernel.org>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Oleg Nesterov <oleg@redhat.com>
CC: Mike Rapoport <rppt@linux.vnet.ibm.com>
CC: Michal Hocko <mhocko@suse.com>
CC: Andy Lutomirski <luto@kernel.org>
CC: "Eric W. Biederman" <ebiederm@xmission.com>
CC: Andrei Vagin <avagin@openvz.org>
CC: Cyrill Gorcunov <gorcunov@openvz.org>
CC: Serge Hallyn <serge@hallyn.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bfedb589252c01fa505ac9f6f2a3d5d68d707ef4 upstream.
During exec dumpable is cleared if the file that is being executed is
not readable by the user executing the file. A bug in
ptrace_may_access allows reading the file if the executable happens to
enter into a subordinate user namespace (aka clone(CLONE_NEWUSER),
unshare(CLONE_NEWUSER), or setns(fd, CLONE_NEWUSER).
This problem is fixed with only necessary userspace breakage by adding
a user namespace owner to mm_struct, captured at the time of exec, so
it is clear in which user namespace CAP_SYS_PTRACE must be present in
to be able to safely give read permission to the executable.
The function ptrace_may_access is modified to verify that the ptracer
has CAP_SYS_ADMIN in task->mm->user_ns instead of task->cred->user_ns.
This ensures that if the task changes it's cred into a subordinate
user namespace it does not become ptraceable.
The function ptrace_attach is modified to only set PT_PTRACE_CAP when
CAP_SYS_PTRACE is held over task->mm->user_ns. The intent of
PT_PTRACE_CAP is to be a flag to note that whatever permission changes
the task might go through the tracer has sufficient permissions for
it not to be an issue. task->cred->user_ns is always the same
as or descendent of mm->user_ns. Which guarantees that having
CAP_SYS_PTRACE over mm->user_ns is the worst case for the tasks
credentials.
To prevent regressions mm->dumpable and mm->user_ns are not considered
when a task has no mm. As simply failing ptrace_may_attach causes
regressions in privileged applications attempting to read things
such as /proc/<pid>/stat
Acked-by: Kees Cook <keescook@chromium.org>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
Fixes: 8409cca705 ("userns: allow ptrace from non-init user namespaces")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If something goes wrong with task stack refcounting and a stack
refcount hits zero too early, warn and leak it rather than
potentially freeing it early (and silently).
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/f29119c783a9680a4b4656e751b6123917ace94b.1477926663.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
extract as much possible uncertainty from a running system at boot time as
possible, hoping to capitalize on any possible variation in CPU operation
(due to runtime data differences, hardware differences, SMP ordering,
thermal timing variation, cache behavior, etc).
At the very least, this plugin is a much more comprehensive example for
how to manipulate kernel code using the gcc plugin internals.
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Merge tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc plugins update from Kees Cook:
"This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot
time as possible, hoping to capitalize on any possible variation in
CPU operation (due to runtime data differences, hardware differences,
SMP ordering, thermal timing variation, cache behavior, etc).
At the very least, this plugin is a much more comprehensive example
for how to manipulate kernel code using the gcc plugin internals"
* tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
latent_entropy: Mark functions with __latent_entropy
gcc-plugins: Add latent_entropy plugin
The __latent_entropy gcc attribute can be used only on functions and
variables. If it is on a function then the plugin will instrument it for
gathering control-flow entropy. If the attribute is on a variable then
the plugin will initialize it with random contents. The variable must
be an integer, an integer array type or a structure with integer fields.
These specific functions have been selected because they are init
functions (to help gather boot-time entropy), are called at unpredictable
times, or they have variable loops, each of which provide some level of
latent entropy.
Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: expanded commit message]
Signed-off-by: Kees Cook <keescook@chromium.org>
This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot time as
possible, hoping to capitalize on any possible variation in CPU operation
(due to runtime data differences, hardware differences, SMP ordering,
thermal timing variation, cache behavior, etc).
At the very least, this plugin is a much more comprehensive example for
how to manipulate kernel code using the gcc plugin internals.
The need for very-early boot entropy tends to be very architecture or
system design specific, so this plugin is more suited for those sorts
of special cases. The existing kernel RNG already attempts to extract
entropy from reliable runtime variation, but this plugin takes the idea to
a logical extreme by permuting a global variable based on any variation
in code execution (e.g. a different value (and permutation function)
is used to permute the global based on loop count, case statement,
if/then/else branching, etc).
To do this, the plugin starts by inserting a local variable in every
marked function. The plugin then adds logic so that the value of this
variable is modified by randomly chosen operations (add, xor and rol) and
random values (gcc generates separate static values for each location at
compile time and also injects the stack pointer at runtime). The resulting
value depends on the control flow path (e.g., loops and branches taken).
Before the function returns, the plugin mixes this local variable into
the latent_entropy global variable. The value of this global variable
is added to the kernel entropy pool in do_one_initcall() and _do_fork(),
though it does not credit any bytes of entropy to the pool; the contents
of the global are just used to mix the pool.
Additionally, the plugin can pre-initialize arrays with build-time
random contents, so that two different kernel builds running on identical
hardware will not have the same starting values.
Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: expanded commit message and code comments]
Signed-off-by: Kees Cook <keescook@chromium.org>
The global zero page is used to satisfy an anonymous read fault. If
THP(Transparent HugePage) is enabled then the global huge zero page is
used. The global huge zero page uses an atomic counter for reference
counting and is allocated/freed dynamically according to its counter
value.
CPU time spent on that counter will greatly increase if there are a lot
of processes doing anonymous read faults. This patch proposes a way to
reduce the access to the global counter so that the CPU load can be
reduced accordingly.
To do this, a new flag of the mm_struct is introduced:
MMF_USED_HUGE_ZERO_PAGE. With this flag, the process only need to touch
the global counter in two cases:
1 The first time it uses the global huge zero page;
2 The time when mm_user of its mm_struct reaches zero.
Note that right now, the huge zero page is eligible to be freed as soon
as its last use goes away. With this patch, the page will not be
eligible to be freed until the exit of the last process from which it
was ever used.
And with the use of mm_user, the kthread is not eligible to use huge
zero page either. Since no kthread is using huge zero page today, there
is no difference after applying this patch. But if that is not desired,
I can change it to when mm_count reaches zero.
Case used for test on Haswell EP:
usemem -n 72 --readonly -j 0x200000 100G
Which spawns 72 processes and each will mmap 100G anonymous space and
then do read only access to that space sequentially with a step of 2MB.
CPU cycles from perf report for base commit:
54.03% usemem [kernel.kallsyms] [k] get_huge_zero_page
CPU cycles from perf report for this commit:
0.11% usemem [kernel.kallsyms] [k] mm_get_huge_zero_page
Performance(throughput) of the workload for base commit: 1784430792
Performance(throughput) of the workload for this commit: 4726928591
164% increase.
Runtime of the workload for base commit: 707592 us
Runtime of the workload for this commit: 303970 us
50% drop.
Link: http://lkml.kernel.org/r/fe51a88f-446a-4622-1363-ad1282d71385@intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After "oom: keep mm of the killed task available" we can safely detect
an oom victim by checking task->signal->oom_mm so we do not need the
signal_struct counter anymore so let's get rid of it.
This alone wouldn't be sufficient for nommu archs because
exit_oom_victim doesn't hide the process from the oom killer anymore.
We can, however, mark the mm with a MMF flag in __mmput. We can reuse
MMF_OOM_REAPED and rename it to a more generic MMF_OOM_SKIP.
Link: http://lkml.kernel.org/r/1472119394-11342-6-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Lockdep complains that __mmdrop is not safe from the softirq context:
=================================
[ INFO: inconsistent lock state ]
4.6.0-oomfortification2-00011-geeb3eadeab96-dirty #949 Tainted: G W
---------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
swapper/1/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
(pgd_lock){+.?...}, at: pgd_free+0x19/0x6b
{SOFTIRQ-ON-W} state was registered at:
__lock_acquire+0xa06/0x196e
lock_acquire+0x139/0x1e1
_raw_spin_lock+0x32/0x41
__change_page_attr_set_clr+0x2a5/0xacd
change_page_attr_set_clr+0x16f/0x32c
set_memory_nx+0x37/0x3a
free_init_pages+0x9e/0xc7
alternative_instructions+0xa2/0xb3
check_bugs+0xe/0x2d
start_kernel+0x3ce/0x3ea
x86_64_start_reservations+0x2a/0x2c
x86_64_start_kernel+0x17a/0x18d
irq event stamp: 105916
hardirqs last enabled at (105916): free_hot_cold_page+0x37e/0x390
hardirqs last disabled at (105915): free_hot_cold_page+0x2c1/0x390
softirqs last enabled at (105878): _local_bh_enable+0x42/0x44
softirqs last disabled at (105879): irq_exit+0x6f/0xd1
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(pgd_lock);
<Interrupt>
lock(pgd_lock);
*** DEADLOCK ***
1 lock held by swapper/1/0:
#0: (rcu_callback){......}, at: rcu_process_callbacks+0x390/0x800
stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Tainted: G W 4.6.0-oomfortification2-00011-geeb3eadeab96-dirty #949
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
Call Trace:
<IRQ>
print_usage_bug.part.25+0x259/0x268
mark_lock+0x381/0x567
__lock_acquire+0x993/0x196e
lock_acquire+0x139/0x1e1
_raw_spin_lock+0x32/0x41
pgd_free+0x19/0x6b
__mmdrop+0x25/0xb9
__put_task_struct+0x103/0x11e
delayed_put_task_struct+0x157/0x15e
rcu_process_callbacks+0x660/0x800
__do_softirq+0x1ec/0x4d5
irq_exit+0x6f/0xd1
smp_apic_timer_interrupt+0x42/0x4d
apic_timer_interrupt+0x8e/0xa0
<EOI>
arch_cpu_idle+0xf/0x11
default_idle_call+0x32/0x34
cpu_startup_entry+0x20c/0x399
start_secondary+0xfe/0x101
More over commit a79e53d856 ("x86/mm: Fix pgd_lock deadlock") was
explicit about pgd_lock not to be called from the irq context. This
means that __mmdrop called from free_signal_struct has to be postponed
to a user context. We already have a similar mechanism for mmput_async
so we can use it here as well. This is safe because mm_count is pinned
by mm_users.
This fixes bug introduced by "oom: keep mm of the killed task available"
Link: http://lkml.kernel.org/r/1472119394-11342-5-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
oom_reap_task has to call exit_oom_victim in order to make sure that the
oom vicim will not block the oom killer for ever. This is, however,
opening new problems (e.g oom_killer_disable exclusion - see commit
7407054209 ("oom, suspend: fix oom_reaper vs. oom_killer_disable
race")). exit_oom_victim should be only called from the victim's
context ideally.
One way to achieve this would be to rely on per mm_struct flags. We
already have MMF_OOM_REAPED to hide a task from the oom killer since
"mm, oom: hide mm which is shared with kthread or global init". The
problem is that the exit path:
do_exit
exit_mm
tsk->mm = NULL;
mmput
__mmput
exit_oom_victim
doesn't guarantee that exit_oom_victim will get called in a bounded
amount of time. At least exit_aio depends on IO which might get blocked
due to lack of memory and who knows what else is lurking there.
This patch takes a different approach. We remember tsk->mm into the
signal_struct and bind it to the signal struct life time for all oom
victims. __oom_reap_task_mm as well as oom_scan_process_thread do not
have to rely on find_lock_task_mm anymore and they will have a reliable
reference to the mm struct. As a result all the oom specific
communication inside the OOM killer can be done via tsk->signal->oom_mm.
Increasing the signal_struct for something as unlikely as the oom killer
is far from ideal but this approach will make the code much more
reasonable and long term we even might want to move task->mm into the
signal_struct anyway. In the next step we might want to make the oom
killer exclusion and access to memory reserves completely independent
which would be also nice.
Link: http://lkml.kernel.org/r/1472119394-11342-4-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull namespace updates from Eric Biederman:
"This set of changes is a number of smaller things that have been
overlooked in other development cycles focused on more fundamental
change. The devpts changes are small things that were a distraction
until we managed to kill off DEVPTS_MULTPLE_INSTANCES. There is an
trivial regression fix to autofs for the unprivileged mount changes
that went in last cycle. A pair of ioctls has been added by Andrey
Vagin making it is possible to discover the relationships between
namespaces when referring to them through file descriptors.
The big user visible change is starting to add simple resource limits
to catch programs that misbehave. With namespaces in general and user
namespaces in particular allowing users to use more kinds of
resources, it has become important to have something to limit errant
programs. Because the purpose of these limits is to catch errant
programs the code needs to be inexpensive to use as it always on, and
the default limits need to be high enough that well behaved programs
on well behaved systems don't encounter them.
To this end, after some review I have implemented per user per user
namespace limits, and use them to limit the number of namespaces. The
limits being per user mean that one user can not exhause the limits of
another user. The limits being per user namespace allow contexts where
the limit is 0 and security conscious folks can remove from their
threat anlysis the code used to manage namespaces (as they have
historically done as it root only). At the same time the limits being
per user namespace allow other parts of the system to use namespaces.
Namespaces are increasingly being used in application sand boxing
scenarios so an all or nothing disable for the entire system for the
security conscious folks makes increasing use of these sandboxes
impossible.
There is also added a limit on the maximum number of mounts present in
a single mount namespace. It is nontrivial to guess what a reasonable
system wide limit on the number of mount structure in the kernel would
be, especially as it various based on how a system is using
containers. A limit on the number of mounts in a mount namespace
however is much easier to understand and set. In most cases in
practice only about 1000 mounts are used. Given that some autofs
scenarious have the potential to be 30,000 to 50,000 mounts I have set
the default limit for the number of mounts at 100,000 which is well
above every known set of users but low enough that the mount hash
tables don't degrade unreaonsably.
These limits are a start. I expect this estabilishes a pattern that
other limits for resources that namespaces use will follow. There has
been interest in making inotify event limits per user per user
namespace as well as interest expressed in making details about what
is going on in the kernel more visible"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (28 commits)
autofs: Fix automounts by using current_real_cred()->uid
mnt: Add a per mount namespace limit on the number of mounts
netns: move {inc,dec}_net_namespaces into #ifdef
nsfs: Simplify __ns_get_path
tools/testing: add a test to check nsfs ioctl-s
nsfs: add ioctl to get a parent namespace
nsfs: add ioctl to get an owning user namespace for ns file descriptor
kernel: add a helper to get an owning user namespace for a namespace
devpts: Change the owner of /dev/pts/ptmx to the mounter of /dev/pts
devpts: Remove sync_filesystems
devpts: Make devpts_kill_sb safe if fsi is NULL
devpts: Simplify devpts_mount by using mount_nodev
devpts: Move the creation of /dev/pts/ptmx into fill_super
devpts: Move parse_mount_options into fill_super
userns: When the per user per user namespace limit is reached return ENOSPC
userns; Document per user per user namespace limits.
mntns: Add a limit on the number of mount namespaces.
netns: Add a limit on the number of net namespaces
cgroupns: Add a limit on the number of cgroup namespaces
ipcns: Add a limit on the number of ipc namespaces
...
vmalloc() is a bit slow, and pounding vmalloc()/vfree() will eventually
force a global TLB flush.
To reduce pressure on them, if CONFIG_VMAP_STACK=y, cache two thread
stacks per CPU. This will let us quickly allocate a hopefully
cache-hot, TLB-hot stack under heavy forking workloads (shell script style).
On my silly pthread_create() benchmark, it saves about 2 µs per
pthread_create()+join() with CONFIG_VMAP_STACK=y.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/94811d8e3994b2e962f88866290017d498eb069c.1474003868.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We currently keep every task's stack around until the task_struct
itself is freed. This means that we keep the stack allocation alive
for longer than necessary and that, under load, we free stacks in
big batches whenever RCU drops the last task reference. Neither of
these is good for reuse of cache-hot memory, and freeing in batches
prevents us from usefully caching small numbers of vmalloced stacks.
On architectures that have thread_info on the stack, we can't easily
change this, but on architectures that set THREAD_INFO_IN_TASK, we
can free it as soon as the task is dead.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/08ca06cde00ebed0046c5d26cbbf3fbb7ef5b812.1474003868.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Merge fixes from Andrew Morton:
"14 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
rapidio/tsi721: fix incorrect detection of address translation condition
rapidio/documentation/mport_cdev: add missing parameter description
kernel/fork: fix CLONE_CHILD_CLEARTID regression in nscd
MAINTAINERS: Vladimir has moved
mm, mempolicy: task->mempolicy must be NULL before dropping final reference
printk/nmi: avoid direct printk()-s from __printk_nmi_flush()
treewide: remove references to the now unnecessary DEFINE_PCI_DEVICE_TABLE
drivers/scsi/wd719x.c: remove last declaration using DEFINE_PCI_DEVICE_TABLE
mm, vmscan: only allocate and reclaim from zones with pages managed by the buddy allocator
lib/test_hash.c: fix warning in preprocessor symbol evaluation
lib/test_hash.c: fix warning in two-dimensional array init
kconfig: tinyconfig: provide whole choice blocks to avoid warnings
kexec: fix double-free when failing to relocate the purgatory
mm, oom: prevent premature OOM killer invocation for high order request
Commit fec1d01152 ("[PATCH] Disable CLONE_CHILD_CLEARTID for abnormal
exit") has caused a subtle regression in nscd which uses
CLONE_CHILD_CLEARTID to clear the nscd_certainly_running flag in the
shared databases, so that the clients are notified when nscd is
restarted. Now, when nscd uses a non-persistent database, clients that
have it mapped keep thinking the database is being updated by nscd, when
in fact nscd has created a new (anonymous) one (for non-persistent
databases it uses an unlinked file as backend).
The original proposal for the CLONE_CHILD_CLEARTID change claimed
(https://lkml.org/lkml/2006/10/25/233):
: The NPTL library uses the CLONE_CHILD_CLEARTID flag on clone() syscalls
: on behalf of pthread_create() library calls. This feature is used to
: request that the kernel clear the thread-id in user space (at an address
: provided in the syscall) when the thread disassociates itself from the
: address space, which is done in mm_release().
:
: Unfortunately, when a multi-threaded process incurs a core dump (such as
: from a SIGSEGV), the core-dumping thread sends SIGKILL signals to all of
: the other threads, which then proceed to clear their user-space tids
: before synchronizing in exit_mm() with the start of core dumping. This
: misrepresents the state of process's address space at the time of the
: SIGSEGV and makes it more difficult for someone to debug NPTL and glibc
: problems (misleading him/her to conclude that the threads had gone away
: before the fault).
:
: The fix below is to simply avoid the CLONE_CHILD_CLEARTID action if a
: core dump has been initiated.
The resulting patch from Roland (https://lkml.org/lkml/2006/10/26/269)
seems to have a larger scope than the original patch asked for. It
seems that limitting the scope of the check to core dumping should work
for SIGSEGV issue describe above.
[Changelog partly based on Andreas' description]
Fixes: fec1d01152 ("[PATCH] Disable CLONE_CHILD_CLEARTID for abnormal exit")
Link: http://lkml.kernel.org/r/1471968749-26173-1-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Tested-by: William Preston <wpreston@suse.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Andreas Schwab <schwab@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull audit fixes from Paul Moore:
"Two small patches to fix some bugs with the audit-by-executable
functionality we introduced back in v4.3 (both patches are marked
for the stable folks)"
* 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit:
audit: fix exe_file access in audit_exe_compare
mm: introduce get_task_exe_file
For more convenient access if one has a pointer to the task.
As a minor nit take advantage of the fact that only task lock + rcu are
needed to safely grab ->exe_file. This saves mm refcount dance.
Use the helper in proc_exe_link.
Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Cc: <stable@vger.kernel.org> # 4.3.x
Signed-off-by: Paul Moore <paul@paul-moore.com>
If CONFIG_VMAP_STACK=y is selected, kernel stacks are allocated with
__vmalloc_node_range().
Grsecurity has had a similar feature (called GRKERNSEC_KSTACKOVERFLOW=y)
for a long time.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/14c07d4fd173a5b117f51e8b939f9f4323e39899.1470907718.git.luto@kernel.org
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
cgroup_threadgroup_rwsem is acquired in read mode during process exit
and fork. It is also grabbed in write mode during
__cgroups_proc_write(). I've recently run into a scenario with lots
of memory pressure and OOM and I am beginning to see
systemd
__switch_to+0x1f8/0x350
__schedule+0x30c/0x990
schedule+0x48/0xc0
percpu_down_write+0x114/0x170
__cgroup_procs_write.isra.12+0xb8/0x3c0
cgroup_file_write+0x74/0x1a0
kernfs_fop_write+0x188/0x200
__vfs_write+0x6c/0xe0
vfs_write+0xc0/0x230
SyS_write+0x6c/0x110
system_call+0x38/0xb4
This thread is waiting on the reader of cgroup_threadgroup_rwsem to
exit. The reader itself is under memory pressure and has gone into
reclaim after fork. There are times the reader also ends up waiting on
oom_lock as well.
__switch_to+0x1f8/0x350
__schedule+0x30c/0x990
schedule+0x48/0xc0
jbd2_log_wait_commit+0xd4/0x180
ext4_evict_inode+0x88/0x5c0
evict+0xf8/0x2a0
dispose_list+0x50/0x80
prune_icache_sb+0x6c/0x90
super_cache_scan+0x190/0x210
shrink_slab.part.15+0x22c/0x4c0
shrink_zone+0x288/0x3c0
do_try_to_free_pages+0x1dc/0x590
try_to_free_pages+0xdc/0x260
__alloc_pages_nodemask+0x72c/0xc90
alloc_pages_current+0xb4/0x1a0
page_table_alloc+0xc0/0x170
__pte_alloc+0x58/0x1f0
copy_page_range+0x4ec/0x950
copy_process.isra.5+0x15a0/0x1870
_do_fork+0xa8/0x4b0
ppc_clone+0x8/0xc
In the meanwhile, all processes exiting/forking are blocked almost
stalling the system.
This patch moves the threadgroup_change_begin from before
cgroup_fork() to just before cgroup_canfork(). There is no nee to
worry about threadgroup changes till the task is actually added to the
threadgroup. This avoids having to call reclaim with
cgroup_threadgroup_rwsem held.
tj: Subject and description edits.
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Zefan Li <lizefan@huawei.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Tejun Heo <tj@kernel.org>