linux/Documentation
Roman Gushchin c643401218 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>
2017-11-17 16:10:00 -08:00
..
ABI f2fs-for-4.15-rc1 2017-11-16 12:10:21 -08:00
accounting
acpi ACPI / LPIT: Add Low Power Idle Table (LPIT) support 2017-10-11 15:38:10 +02:00
admin-guide powerpc updates for 4.15 2017-11-16 12:47:46 -08:00
aoe
arm ARM: sunxi: add support for R40 SoC 2017-09-22 21:57:09 +02:00
arm64 arm64 updates for 4.15 2017-11-15 10:56:56 -08:00
auxdisplay
backlight
blackfin
block block: remove __bio_kmap_atomic 2017-11-10 19:53:25 -07:00
blockdev SCSI misc on 20170907 2017-09-07 21:11:05 -07:00
bpf bpf: document answers to common questions about BPF 2017-11-01 21:01:47 +09:00
bus-devices
cdrom documentation: Update ide-cd documentation to reflect CONFIG_BLK_DEV_HD_IDE removal 2017-10-12 11:25:31 -06:00
cgroup-v1
cma
connector
console
core-api A relatively calm cycle for the docs tree again. 2017-11-13 08:25:06 -08:00
cpu-freq cpufreq: stats: Handle the case when trans_table goes beyond PAGE_SIZE 2017-11-08 23:41:25 +01:00
cpuidle
cris
crypto crypto: doc - adapt api sample to use async. op wait 2017-11-03 22:11:23 +08:00
dev-tools kmemcheck: rip it out 2017-11-15 18:21:05 -08:00
device-mapper dm raid: fix incorrect status output at the end of a "recover" process 2017-10-05 16:21:30 -04:00
devicetree ARM: SoC driver updates for v4.15 2017-11-16 16:05:01 -08:00
doc-guide Documentation: fix ref to sphinx/kerneldoc.py 2017-10-19 12:57:10 -06:00
driver-api This is the bulk of pin control changes for the v4.15 2017-11-16 10:57:11 -08:00
driver-model driver core: remove DRIVER_ATTR 2017-09-19 09:20:33 +02:00
early-userspace
EDID
extcon
fault-injection cpu/hotplug: Get rid of CPU hotplug notifier leftovers 2017-11-13 10:03:53 +01:00
fb documentation: fb: update list of available compiled-in fonts 2017-11-08 03:39:52 -07:00
features Documentation/features/KASAN: mark KASAN as supported only on 64-bit on x86 2017-10-03 14:40:22 -06:00
filesystems proc, coredump: add CoreDumping flag to /proc/pid/status 2017-11-17 16:10:00 -08:00
firmware_class
fmc
fpga
frv
gpio Merge branch 'gpio-irqchip-rework' of /home/linus/linux-gpio into devel 2017-11-09 09:38:42 +01:00
gpu drm: some KMS todo ideas 2017-10-18 10:15:02 +02:00
hid Documentation: fix input related doc refs 2017-10-12 11:14:06 -06:00
hwmon pmbus: Add driver for Maxim MAX31785 Intelligent Fan Controller 2017-11-05 06:06:33 -08:00
i2c i2c: i801: Add support for Intel Cedar Fork 2017-10-05 14:44:56 +02:00
ia64
ide
iio
infiniband
input Documentation: fix input related doc refs 2017-10-12 11:14:06 -06:00
ioctl
isdn
kbuild DeviceTree for 4.15: 2017-11-14 18:25:40 -08:00
kdump
kernel-hacking
laptops Documentation: fix admin-guide doc refs 2017-10-12 11:13:28 -06:00
leds Documentation: leds: Update 00-INDEX file 2017-10-23 20:17:03 +02:00
lightnvm
livepatch livepatch: add (un)patch callbacks 2017-10-19 10:08:56 +02:00
locking Documentation: fix locking rt-mutex doc refs 2017-10-19 12:56:44 -06:00
m68k
md md-cluster: update document for raid10 2017-11-01 21:32:25 -07:00
media media updates for v4.15-rc1 2017-11-15 20:30:12 -08:00
memory-devices
metag
mic
mips
misc-devices
mmc
mn10300
mtd
namespaces
netlabel
networking Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-11-15 11:56:19 -08:00
nfc
nios2
nvdimm
nvmem
openrisc Documentation: openrisc: Updates to README 2017-10-30 21:37:53 +09:00
parisc
PCI
pcmcia
perf Documentation: perf: hisi: Documentation for HiSilicon SoC PMU driver 2017-10-19 17:06:34 +01:00
phy
platform
power Power management updates for v4.15-rc1 2017-11-13 19:43:50 -08:00
powerpc
pps drivers/pps: aesthetic tweaks to PPS-related content 2017-09-08 18:26:51 -07:00
process A relatively calm cycle for the docs tree again. 2017-11-13 08:25:06 -08:00
pti
ptp
rapidio
RCU Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 12:18:10 -08:00
s390
scheduler
scsi scsi: smartpqi: correct spelling error in documentation 2017-10-23 04:15:17 -04:00
security Documentation: fix security related doc refs 2017-10-12 11:14:40 -06:00
serial
sh
sound sound updates for 4.15-rc1 2017-11-14 18:01:46 -08:00
sparc
sphinx
sphinx-static
spi
sysctl mm, sysctl: make NUMA stats configurable 2017-11-15 18:21:07 -08:00
target
thermal
timers docs: highres: fix broken urls 2017-09-26 14:58:23 -06:00
trace Char/Misc patches for 4.15-rc1 2017-11-16 09:10:59 -08:00
translations This is the bulk of pin control changes for the v4.15 2017-11-16 10:57:11 -08:00
usb Documentation: fix usb related doc refs 2017-10-12 11:15:48 -06:00
userspace-api
virtual KVM: s390: fixes and improvements for 4.15 2017-11-16 14:39:46 +01:00
vm mm/mmu_notifier: avoid double notification when it is useless 2017-11-15 18:21:03 -08:00
w1 add w1_ds28e17 driver for the DS28E17 Onewire to I2C master bridge 2017-10-04 10:29:22 +02:00
watchdog Documentation: fix selftests related file refs 2017-10-19 12:58:21 -06:00
wimax
x86 Merge branch 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 19:05:19 -08:00
xtensa
.gitignore
00-INDEX
atomic_bitops.txt
atomic_t.txt
bcache.txt
bt8xxgpio.txt
btmrvl.txt
bus-virt-phys-mapping.txt
cachetlb.txt
cgroup-v2.txt cgroup, sched: Move basic cpu stats from cgroup.stat to cpu.stat 2017-10-26 10:56:33 -07:00
Changes
circular-buffers.txt
clk.txt
CodingStyle
conf.py docs-rst: don't require adjustbox anymore 2017-09-08 10:02:55 -06:00
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
digsig.txt
DMA-API-HOWTO.txt
DMA-API.txt
DMA-attributes.txt
DMA-ISA-LPC.txt
docutils.conf
dontdiff
efi-stub.txt
eisa.txt
errseq.rst
flexible-arrays.txt
futex-requeue-pi.txt
gcc-plugins.txt
highuid.txt
hw_random.txt
hwspinlock.txt
index.rst
intel_txt.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt ipmi: Make IPMI panic strings always available 2017-09-27 16:03:45 -05:00
IRQ-affinity.txt
IRQ-domain.txt
IRQ.txt
irqflags-tracing.txt
isa.txt
isapnp.txt
kernel-doc-nano-HOWTO.txt
kernel-per-CPU-kthreads.txt
kobject.txt
kprobes.txt kprobes/docs: Remove jprobes related documents 2017-10-20 11:02:55 +02:00
kref.txt
ldm.txt
lockup-watchdogs.txt
logo.gif
logo.txt
lsm.txt
lzo.txt
mailbox.txt
Makefile Documentation: add script and build target to check for broken file references 2017-10-12 11:07:42 -06:00
memory-barriers.txt Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 12:38:26 -08:00
memory-hotplug.txt
men-chameleon-bus.txt
nommu-mmap.txt
ntb.txt
numastat.txt
padata.txt
parport-lowlevel.txt
percpu-rw-semaphore.txt
phy.txt
pi-futex.txt Documentation: fix locking rt-mutex doc refs 2017-10-19 12:56:44 -06:00
pnp.txt
preempt-locking.txt
printk-formats.txt
pwm.txt
rbtree.txt rbtree: cache leftmost node internally 2017-09-08 18:26:48 -07:00
remoteproc.txt
rfkill.txt
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt
SAK.txt
sgi-ioc4.txt
siphash.txt
SM501.txt
smsc_ece1099.txt
static-keys.txt
SubmittingPatches
svga.txt
switchtec.txt
sync_file.txt
tee.txt
this_cpu_ops.txt
unaligned-memory-access.txt
vfio-mediated-device.txt
vfio.txt
video-output.txt
xillybus.txt
xz.txt
zorro.txt