linux.git/kernel/tsacct.c, branch v6.18.21

pid: change bacct_add_tsk() to use task_ppid_nr_ns()

2025-08-19T11:38:20+00:00

to simplify the code.

Signed-off-by: Oleg Nesterov 
Link: https://lore.kernel.org/20250810173615.GA20000@redhat.com
Signed-off-by: Christian Brauner

tsacct: replace strncpy() with strscpy()

2024-07-12T23:39:53+00:00

Replace the deprecated[1] use of strncpy() in bacct_add_tsk().  Since this
is UAPI, include trailing padding in the copy.

Link: https://github.com/KSPP/linux/issues/90 [1]
Link: https://lkml.kernel.org/r/20240711171308.work.995-kees@kernel.org
Signed-off-by: Kees Cook 
Cc: "Dr. Thomas Orgis" 
Cc: Eric W. Biederman 
Cc: Ismael Luceno 
Cc: Peng Liu 
Signed-off-by: Andrew Morton

taskstats: version 12 with thread group and exe info

2022-04-29T21:38:03+00:00

The task exit struct needs some crucial information to be able to provide
an enhanced version of process and thread accounting.  This change
provides:

1. ac_tgid in additon to ac_pid
2. thread group execution walltime in ac_tgetime
3. flag AGROUP in ac_flag to indicate the last task
   in a thread group / process
4. device ID and inode of task's /proc/self/exe in
   ac_exe_dev and ac_exe_inode
5. tools/accounting/procacct as demonstrator

When a task exits, taskstats are reported to userspace including the
task's pid and ppid, but without the id of the thread group this task is
part of.  Without the tgid, the stats of single tasks cannot be correlated
to each other as a thread group (process).

The taskstats documentation suggests that on process exit a data set
consisting of accumulated stats for the whole group is produced.  But such
an additional set of stats is only produced for actually multithreaded
processes, not groups that had only one thread, and also those stats only
contain data about delay accounting and not the more basic information
about CPU and memory resource usage.  Adding the AGROUP flag to be set
when the last task of a group exited enables determination of process end
also for single-threaded processes.

My applicaton basically does enhanced process accounting with summed
cputime, biggest maxrss, tasks per process.  The data is not available
with the traditional BSD process accounting (which is not designed to be
extensible) and the taskstats interface allows more efficient on-the-fly
grouping and summing of the stats, anyway, without intermediate disk
writes.

Furthermore, I do carry statistics on which exact program binary is used
how often with associated resources, getting a picture on how important
which parts of a collection of installed scientific software in different
versions are, and how well they put load on the machine.  This is enabled
by providing information on /proc/self/exe for each task.  I assume the
two 64-bit fields for device ID and inode are more appropriate than the
possibly large resolved path to keep the data volume down.

Add the tgid to the stats to complete task identification, the flag AGROUP
to mark the last task of a group, the group wallclock time, and
inode-based identification of the associated executable file.

Add tools/accounting/procacct.c as a simplified fork of getdelays.c to
demonstrate process and thread accounting.

[thomas.orgis@uni-hamburg.de: fix version number in comment]
  Link: https://lkml.kernel.org/r/20220405003601.7a5f6008@plasteblaster
Link: https://lkml.kernel.org/r/20220331004106.64e5616b@plasteblaster
Signed-off-by: Dr. Thomas Orgis 
Reviewed-by: Ismael Luceno 
Cc: Balbir Singh 
Cc: Eric W. Biederman 
Cc: xu xin 
Cc: Yang Yang 
Signed-off-by: Andrew Morton

taskstats: Cleanup the use of task->exit_code

2022-01-08T18:43:57+00:00

In the function bacct_add_task the code reading task->exit_code was
introduced in commit f3cef7a99469 ("[PATCH] csa: basic accounting over
taskstats"), and it is not entirely clear what the taskstats interface
is trying to return as only returning the exit_code of the first task
in a process doesn't make a lot of sense.

As best as I can figure the intent is to return task->exit_code after
a task exits.  The field is returned with per task fields, so the
exit_code of the entire process is not wanted.  Only the value of the
first task is returned so this is not a useful way to get the per task
ptrace stop code.  The ordinary case of returning this value is
returning after a task exits, which also precludes use for getting
a ptrace value.

It is common to for the first task of a process to also be the last
task of a process so this field may have done something reasonable by
accident in testing.

Make ac_exitcode a reliable per task value by always returning it for
every exited task.

Setting ac_exitcode in a sensible mannter makes it possible to continue
to provide this value going forward.

Cc: Balbir Singh 
Fixes: f3cef7a99469 ("[PATCH] csa: basic accounting over taskstats")
Link: https://lkml.kernel.org/r/20220103213312.9144-5-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman"

mm/mmap.c: fix a data race of mm->total_vm

2021-11-06T20:30:35+00:00

The variable mm->total_vm could be accessed concurrently during mmaping
and system accounting as noticed by KCSAN,

  BUG: KCSAN: data-race in __acct_update_integrals / mmap_region

  read-write to 0xffffa40267bd14c8 of 8 bytes by task 15609 on cpu 3:
   mmap_region+0x6dc/0x1400
   do_mmap+0x794/0xca0
   vm_mmap_pgoff+0xdf/0x150
   ksys_mmap_pgoff+0xe1/0x380
   do_syscall_64+0x37/0x50
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

  read to 0xffffa40267bd14c8 of 8 bytes by interrupt on cpu 2:
   __acct_update_integrals+0x187/0x1d0
   acct_account_cputime+0x3c/0x40
   update_process_times+0x5c/0x150
   tick_sched_timer+0x184/0x210
   __run_hrtimer+0x119/0x3b0
   hrtimer_interrupt+0x350/0xaa0
   __sysvec_apic_timer_interrupt+0x7b/0x220
   asm_call_irq_on_stack+0x12/0x20
   sysvec_apic_timer_interrupt+0x4d/0x80
   asm_sysvec_apic_timer_interrupt+0x12/0x20
   smp_call_function_single+0x192/0x2b0
   perf_install_in_context+0x29b/0x4a0
   __se_sys_perf_event_open+0x1a98/0x2550
   __x64_sys_perf_event_open+0x63/0x70
   do_syscall_64+0x37/0x50
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

  Reported by Kernel Concurrency Sanitizer on:
  CPU: 2 PID: 15610 Comm: syz-executor.3 Not tainted 5.10.0+ #2
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
  Ubuntu-1.8.2-1ubuntu1 04/01/2014

In vm_stat_account which called by mmap_region, increase total_vm, and
__acct_update_integrals may read total_vm at the same time.  This will
cause a data race which lead to undefined behaviour.  To avoid potential
bad read/write, volatile property and barrier are both used to avoid
undefined behaviour.

Link: https://lkml.kernel.org/r/20210913105550.1569419-1-liupeng256@huawei.com
Signed-off-by: Peng Liu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tsacct: add 64-bit btime field

2019-12-18T17:07:31+00:00

As there is only a 32-bit ac_btime field in taskstat and
we should handle dates after the overflow, add a new field
with the same information but 64-bit width that can hold
a full time64_t.

Signed-off-by: Arnd Bergmann

acct: stop using get_seconds()

2019-12-18T17:07:31+00:00

In 'struct acct', 'struct acct_v3', and 'struct taskstats' we have
a 32-bit 'ac_btime' field containing an absolute time value, which
will overflow in year 2106.

There are two possible ways to deal with it:

a) let it overflow and have user space code deal with reconstructing
   the data based on the current time, or
b) truncate the times based on the range of the u32 type.

Neither of them solves the actual problem. Pick the second
one to best document what the issue is, and have someone
fix it in a future version.

Signed-off-by: Arnd Bergmann

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157

2019-05-30T18:26:37+00:00

Based on 3 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] this program is distributed in the hope that
  it will be useful but without any warranty without even the implied
  warranty of merchantability or fitness for a particular purpose see
  the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] this program is distributed in the hope
  that it will be useful but without any warranty without even the
  implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Richard Fontana 
Reviewed-by: Kate Stewart 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman

sched/headers: Prepare to move cputime functionality from into

2017-03-02T07:42:39+00:00

Introduce a trivial, mostly empty  header
to prepare for the moving of cputime functionality out of sched.h.

Update all code that relies on these facilities.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:29+00:00

We are going to split  out of , which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder  file that just
maps to  to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar