proc, coredump: add CoreDumping flag to /proc/pid/status

Right now there is no convenient way to check if a process is being
coredumped at the moment.

It might be necessary to recognize such state

proc, coredump: add CoreDumping flag to /proc/pid/status

Right now there is no convenient way to check if a process is being
coredumped at the moment.

It might be necessary to recognize such state to prevent killing the
process and getting a broken coredump. Writing a large core might take
significant time, and the process is unresponsive during it, so it might
be killed by timeout, if another process is monitoring and
killing/restarting hanging tasks.

We're getting a significant number of corrupted coredump files on
machines in our fleet, just because processes are being killed by
timeout in the middle of the core writing process.

We do have a process health check, and some agent is responsible for
restarting processes which are not responding for health check requests.
Writing a large coredump to the disk can easily exceed the reasonable
timeout (especially on an overloaded machine).

This flag will allow the agent to distinguish processes which are being
coredumped, extend the timeout for them, and let them produce a full
coredump file.

To provide an ability to detect if a process is in the state of being
coredumped, we can expose a boolean CoreDumping flag in
/proc/pid/status.

Example:
$ cat core.sh
#!/bin/sh

echo "|/usr/bin/sleep 10" > /proc/sys/kernel/core_pattern
sleep 1000 &
PID=$!

cat /proc/$PID/status | grep CoreDumping
kill -ABRT $PID
sleep 1
cat /proc/$PID/status | grep CoreDumping

$ ./core.sh
CoreDumping: 0
CoreDumping: 1

[guro@fb.com: document CoreDumping flag in /proc/<pid>/status]
Link: http://lkml.kernel.org/r/20170928135357.GA8470@castle.DHCP.thefacebook.com
Link: http://lkml.kernel.org/r/20170920230634.31572-1-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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Merge branch 'for-4.15/dax' into libnvdimm-for-next

Merge branch 'for-4.15/alps' into for-linus

- New ALPS touchpad (T4, found currently on HP EliteBook 1000, Zbook Stduio
and HP Elite book x360) support from Masaki Ota

Merge branch 'linus' into timers/urgent

Get upstream changes so dependent patches can be applied.

Merge branch 'linus' into core/objtool, to pick up dependent commits

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge branch 'next' into for-linus

Prepare input updates for 4.15 merge window.

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:
"The main updates in this cycle were:

- Group balancing enh

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:
"The main updates in this cycle were:

- Group balancing enhancements and cleanups (Brendan Jackman)

- Move CPU isolation related functionality into its separate
kernel/sched/isolation.c file, with related 'housekeeping_*()'
namespace and nomenclature et al. (Frederic Weisbecker)

- Improve the interactive/cpu-intense fairness calculation (Josef
Bacik)

- Improve the PELT code and related cleanups (Peter Zijlstra)

- Improve the logic of pick_next_task_fair() (Uladzislau Rezki)

- Improve the RT IPI based balancing logic (Steven Rostedt)

- Various micro-optimizations:

- better !CONFIG_SCHED_DEBUG optimizations (Patrick Bellasi)

- better idle loop (Cheng Jian)

- ... plus misc fixes, cleanups and updates"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
sched/core: Optimize sched_feat() for !CONFIG_SCHED_DEBUG builds
sched/sysctl: Fix attributes of some extern declarations
sched/isolation: Document isolcpus= boot parameter flags, mark it deprecated
sched/isolation: Add basic isolcpus flags
sched/isolation: Move isolcpus= handling to the housekeeping code
sched/isolation: Handle the nohz_full= parameter
sched/isolation: Introduce housekeeping flags
sched/isolation: Split out new CONFIG_CPU_ISOLATION=y config from CONFIG_NO_HZ_FULL
sched/isolation: Rename is_housekeeping_cpu() to housekeeping_cpu()
sched/isolation: Use its own static key
sched/isolation: Make the housekeeping cpumask private
sched/isolation: Provide a dynamic off-case to housekeeping_any_cpu()
sched/isolation, watchdog: Use housekeeping_cpumask() instead of ad-hoc version
sched/isolation: Move housekeeping related code to its own file
sched/idle: Micro-optimize the idle loop
sched/isolcpus: Fix "isolcpus=" boot parameter handling when !CONFIG_CPUMASK_OFFSTACK
x86/tsc: Append the 'tsc=' description for the 'tsc=unstable' boot parameter
sched/rt: Simplify the IPI based RT balancing logic
block/ioprio: Use a helper to check for RT prio
sched/rt: Add a helper to test for a RT task
...

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Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core locking updates from Ingo Molnar:
"The main changes in this cycle are:

- Another attempt

Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core locking updates from Ingo Molnar:
"The main changes in this cycle are:

- Another attempt at enabling cross-release lockdep dependency
tracking (automatically part of CONFIG_PROVE_LOCKING=y), this time
with better performance and fewer false positives. (Byungchul Park)

- Introduce lockdep_assert_irqs_enabled()/disabled() and convert
open-coded equivalents to lockdep variants. (Frederic Weisbecker)

- Add down_read_killable() and use it in the VFS's iterate_dir()
method. (Kirill Tkhai)

- Convert remaining uses of ACCESS_ONCE() to
READ_ONCE()/WRITE_ONCE(). Most of the conversion was Coccinelle
driven. (Mark Rutland, Paul E. McKenney)

- Get rid of lockless_dereference(), by strengthening Alpha atomics,
strengthening READ_ONCE() with smp_read_barrier_depends() and thus
being able to convert users of lockless_dereference() to
READ_ONCE(). (Will Deacon)

- Various micro-optimizations:

- better PV qspinlocks (Waiman Long),
- better x86 barriers (Michael S. Tsirkin)
- better x86 refcounts (Kees Cook)

- ... plus other fixes and enhancements. (Borislav Petkov, Juergen
Gross, Miguel Bernal Marin)"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
locking/x86: Use LOCK ADD for smp_mb() instead of MFENCE
rcu: Use lockdep to assert IRQs are disabled/enabled
netpoll: Use lockdep to assert IRQs are disabled/enabled
timers/posix-cpu-timers: Use lockdep to assert IRQs are disabled/enabled
sched/clock, sched/cputime: Use lockdep to assert IRQs are disabled/enabled
irq_work: Use lockdep to assert IRQs are disabled/enabled
irq/timings: Use lockdep to assert IRQs are disabled/enabled
perf/core: Use lockdep to assert IRQs are disabled/enabled
x86: Use lockdep to assert IRQs are disabled/enabled
smp/core: Use lockdep to assert IRQs are disabled/enabled
timers/hrtimer: Use lockdep to assert IRQs are disabled/enabled
timers/nohz: Use lockdep to assert IRQs are disabled/enabled
workqueue: Use lockdep to assert IRQs are disabled/enabled
irq/softirqs: Use lockdep to assert IRQs are disabled/enabled
locking/lockdep: Add IRQs disabled/enabled assertion APIs: lockdep_assert_irqs_enabled()/disabled()
locking/pvqspinlock: Implement hybrid PV queued/unfair locks
locking/rwlocks: Fix comments
x86/paravirt: Set up the virt_spin_lock_key after static keys get initialized
block, locking/lockdep: Assign a lock_class per gendisk used for wait_for_completion()
workqueue: Remove now redundant lock acquisitions wrt. workqueue flushes
...

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Merge branches 'iommu/arm/smmu', 'iommu/updates', 'iommu/vt-d', 'iommu/ipmmu-vmsa' and 'iommu/iova' into iommu-next-20171113.0

Merge tag 'asoc-v4.15' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Updates for v4.15

The biggest thing this release has been the conversion of the AC98 bus

Merge tag 'asoc-v4.15' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Updates for v4.15

The biggest thing this release has been the conversion of the AC98 bus
to the driver model, that's been a long time coming so thanks to Robert
Jarzmik for his dedication there. Due to there being some AC97 MFD
there's a few fairly large changes in input and the MFD layer, mainly to
the wm97xx driver.

There's also some drivers/drm changes to support the new AMD Stoney
platform, these are shared with the DRM subsystem and should be being
merged via both.

Within the subsystem the overwhelming bulk of the changes is in the
Intel drivers which continue to need lots of cleanups and fixes, this
release they've also gained support for their open source firmware.
There's also some large changs in the core as Morimoto-san continues to
mirror operations into the component level in preparation for conversion
of drivers to that.

- The AC97 bus has finally caught up with the driver model thanks to
some dedicated and persistent work from Robert Jarzmik.
- Continued work from Morimoto-san on moving us towards being able to
use components for everything.
- Lots of cleanups for the Intel platform code, including support for
their open source audio firmware.
- Support for scaling MCLK with sample rate in simple-card.
- Support for AMD Stoney platform.

show more ...

Merge tag 'v4.14' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/torvalds/linux

Linux 4.14

Merge branch 'linus' into x86/platform, to refresh the branch

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge branch 'pm-qos' into pm-cpuidle

Merge branch 'linus' into sched/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge tag 'v4.14-rc8' into next

Merge with mainline to bring in SPDX markings to avoid annoying merge
problems when some header files get deleted.

Merge branch 'linus' into x86/asm, to pick up fixes and resolve conflicts

Conflicts:
arch/x86/kernel/cpu/Makefile

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge branch 'linus' into x86/apic, to resolve conflicts

Conflicts:
arch/x86/include/asm/x2apic.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge branch 'linus' into core/objtool, to pick up dependent fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>

Merge branch 'linus' into locking/core, to resolve conflicts

Conflicts:
include/linux/compiler-clang.h
include/linux/compiler-gcc.h
include/linux/compiler-intel.h
include/uapi/linux/stddef.h

Si

Merge branch 'linus' into locking/core, to resolve conflicts

Conflicts:
include/linux/compiler-clang.h
include/linux/compiler-gcc.h
include/linux/compiler-intel.h
include/uapi/linux/stddef.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>

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Merge branch 'linus' into perf/core, to fix conflicts

Conflicts:
tools/perf/arch/arm/annotate/instructions.c
tools/perf/arch/arm64/annotate/instructions.c
tools/perf/arch/powerpc/annotate/instruc

Merge branch 'linus' into perf/core, to fix conflicts

Conflicts:
tools/perf/arch/arm/annotate/instructions.c
tools/perf/arch/arm64/annotate/instructions.c
tools/perf/arch/powerpc/annotate/instructions.c
tools/perf/arch/s390/annotate/instructions.c
tools/perf/arch/x86/tests/intel-cqm.c
tools/perf/ui/tui/progress.c
tools/perf/util/zlib.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>

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Merge branch 'linus' into core/urgent, to pick up dependent commits

We want to fix an objtool build warning that got introduced in the latest upstream kernel.

Signed-off-by: Ingo Molnar <mingo@kern

Merge branch 'linus' into core/urgent, to pick up dependent commits

We want to fix an objtool build warning that got introduced in the latest upstream kernel.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

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Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

Files removed in 'net-next' had their license header updated
in 'net'. We take the remove from 'net-next'.

Signed-off-by: David S. Mil

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

Files removed in 'net-next' had their license header updated
in 'net'. We take the remove from 'net-next'.

Signed-off-by: David S. Miller <davem@davemloft.net>

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Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux

Merge 4.14-rc3 in order to pick up the new timer_setup function.

Merge branch 'i2c/cht-wc-fusb302-immutable' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c/cht-wc-fusb302-immutable immutable branch from Wolfram Sang:

as discussed before, her

Merge branch 'i2c/cht-wc-fusb302-immutable' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c/cht-wc-fusb302-immutable immutable branch from Wolfram Sang:

as discussed before, here is the immutable branch for the i2c-cht-wc
driver, so you can safely apply Hans' patch [1]

"platform/x86: intel_cht_int33fe: Update fusb302 type string, add properties"

on top of this.

[1] http://patchwork.ozlabs.org/patch/824314/

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Merge branch 'linus' into perf/urgent, to pick up dependent commits

Signed-off-by: Ingo Molnar <mingo@kernel.org>