linux-stable.git/kernel/cgroup/cgroup.c, branch v4.15

cgroup: make cgroup.threads delegatable

2018-01-10T17:42:32+00:00

Make cgroup.threads file delegatable.
The behavior of cgroup.threads should follow the behavior of cgroup.procs.

Signed-off-by: Roman Gushchin 
Discovered-by: Michael Kerrisk 
Cc: Tejun Heo 
Signed-off-by: Tejun Heo

cgroup: fix css_task_iter crash on CSS_TASK_ITER_PROC

2017-12-20T15:09:19+00:00

While teaching css_task_iter to handle skipping over tasks which
aren't group leaders, bc2fb7ed089f ("cgroup: add @flags to
css_task_iter_start() and implement CSS_TASK_ITER_PROCS") introduced a
silly bug.

CSS_TASK_ITER_PROCS is implemented by repeating
css_task_iter_advance() while the advanced cursor is pointing to a
non-leader thread.  However, the cursor variable, @l, wasn't updated
when the iteration has to advance to the next css_set and the
following repetition would operate on the terminal @l from the
previous iteration which isn't pointing to a valid task leading to
oopses like the following or infinite looping.

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000254
  IP: __task_pid_nr_ns+0xc7/0xf0
  PGD 0 P4D 0
  Oops: 0000 [#1] SMP
  ...
  CPU: 2 PID: 1 Comm: systemd Not tainted 4.14.4-200.fc26.x86_64 #1
  Hardware name: System manufacturer System Product Name/PRIME B350M-A, BIOS 3203 11/09/2017
  task: ffff88c4baee8000 task.stack: ffff96d5c3158000
  RIP: 0010:__task_pid_nr_ns+0xc7/0xf0
  RSP: 0018:ffff96d5c315bd50 EFLAGS: 00010206
  RAX: 0000000000000000 RBX: ffff88c4b68c6000 RCX: 0000000000000250
  RDX: ffffffffa5e47960 RSI: 0000000000000000 RDI: ffff88c490f6ab00
  RBP: ffff96d5c315bd50 R08: 0000000000001000 R09: 0000000000000005
  R10: ffff88c4be006b80 R11: ffff88c42f1b8004 R12: ffff96d5c315bf18
  R13: ffff88c42d7dd200 R14: ffff88c490f6a510 R15: ffff88c4b68c6000
  FS:  00007f9446f8ea00(0000) GS:ffff88c4be680000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000254 CR3: 00000007f956f000 CR4: 00000000003406e0
  Call Trace:
   cgroup_procs_show+0x19/0x30
   cgroup_seqfile_show+0x4c/0xb0
   kernfs_seq_show+0x21/0x30
   seq_read+0x2ec/0x3f0
   kernfs_fop_read+0x134/0x180
   __vfs_read+0x37/0x160
   ? security_file_permission+0x9b/0xc0
   vfs_read+0x8e/0x130
   SyS_read+0x55/0xc0
   entry_SYSCALL_64_fastpath+0x1a/0xa5
  RIP: 0033:0x7f94455f942d
  RSP: 002b:00007ffe81ba2d00 EFLAGS: 00000293 ORIG_RAX: 0000000000000000
  RAX: ffffffffffffffda RBX: 00005574e2233f00 RCX: 00007f94455f942d
  RDX: 0000000000001000 RSI: 00005574e2321a90 RDI: 000000000000002b
  RBP: 0000000000000000 R08: 00005574e2321a90 R09: 00005574e231de60
  R10: 00007f94458c8b38 R11: 0000000000000293 R12: 00007f94458c8ae0
  R13: 00007ffe81ba3800 R14: 0000000000000000 R15: 00005574e2116560
  Code: 04 74 0e 89 f6 48 8d 04 76 48 8d 04 c5 f0 05 00 00 48 8b bf b8 05 00 00 48 01 c7 31 c0 48 8b 0f 48 85 c9 74 18 8b b2 30 08 00 00 <3b> 71 04 77 0d 48 c1 e6 05 48 01 f1 48 3b 51 38 74 09 5d c3 8b
  RIP: __task_pid_nr_ns+0xc7/0xf0 RSP: ffff96d5c315bd50

Fix it by moving the initialization of the cursor below the repeat
label.  While at it, rename it to @next for readability.

Signed-off-by: Tejun Heo 
Fixes: bc2fb7ed089f ("cgroup: add @flags to css_task_iter_start() and implement CSS_TASK_ITER_PROCS")
Cc: stable@vger.kernel.org # v4.14+
Reported-by: Laura Abbott 
Reported-by: Bronek Kozicki 
Reported-by: George Amanakis 
Signed-off-by: Tejun Heo

cgroup: use strlcpy() instead of strscpy() to avoid spurious warning

2017-12-15T13:09:47+00:00

As long as cft->name is guaranteed to be NUL-terminated, using strlcpy() would
work just as well and avoid that warning, so the change below could be folded
into that commit.

Signed-off-by: Arnd Bergmann 
Signed-off-by: Tejun Heo

cgroup: avoid copying strings longer than the buffers

2017-12-12T15:53:29+00:00

cgroup root name and file name have max length limit, we should
avoid copying longer name than that to the name.

tj: minor update to $SUBJ.

Signed-off-by: Ma Shimiao 
Signed-off-by: Tejun Heo

Merge branch 'for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2017-11-15T22:29:44+00:00

Pull cgroup updates from Tejun Heo:
 "Cgroup2 cpu controller support is finally merged.

   - Basic cpu statistics support to allow monitoring by default without
     the CPU controller enabled.

   - cgroup2 cpu controller support.

   - /sys/kernel/cgroup files to help dealing with new / optional
     features"

* 'for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: export list of cgroups v2 features using sysfs
  cgroup: export list of delegatable control files using sysfs
  cgroup: mark @cgrp __maybe_unused in cpu_stat_show()
  MAINTAINERS: relocate cpuset.c
  cgroup, sched: Move basic cpu stats from cgroup.stat to cpu.stat
  sched: Implement interface for cgroup unified hierarchy
  sched: Misc preps for cgroup unified hierarchy interface
  sched/cputime: Add dummy cputime_adjust() implementation for CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
  cgroup: statically initialize init_css_set->dfl_cgrp
  cgroup: Implement cgroup2 basic CPU usage accounting
  cpuacct: Introduce cgroup_account_cputime[_field]()
  sched/cputime: Expose cputime_adjust()

cgroup: export list of cgroups v2 features using sysfs

2017-11-06T20:01:57+00:00

The active development of cgroups v2 sometimes leads to a creation
of interfaces, which are not turned on by default (to provide
backward compatibility). It's handy to know from userspace, which
cgroup v2 features are supported without calculating it based
on the kernel version. So, let's export the list of such features
using /sys/kernel/cgroup/features pseudo-file.

The list is hardcoded and has to be extended when new functionality
is added. Each feature is printed on a new line.

Example:
  $ cat /sys/kernel/cgroup/features
  nsdelegate

Signed-off-by: Roman Gushchin 
Cc: Tejun Heo 
Cc: kernel-team@fb.com
Signed-off-by: Tejun Heo

cgroup: export list of delegatable control files using sysfs

2017-11-06T20:01:54+00:00

Delegatable cgroup v2 control files may require special handling
(e.g. chowning), and the exact list of such files varies between
kernel versions (and likely to be extended in the future).

To guarantee correctness of this list and simplify the life
of userspace (systemd, first of all), let's export the list
via /sys/kernel/cgroup/delegate pseudo-file.

Format is siple: each control file name is printed on a new line.
Example:
  $ cat /sys/kernel/cgroup/delegate
  cgroup.procs
  cgroup.subtree_control

Signed-off-by: Roman Gushchin 
Cc: Tejun Heo 
Cc: kernel-team@fb.com
Signed-off-by: Tejun Heo

cgroup: mark @cgrp __maybe_unused in cpu_stat_show()

2017-10-30T15:13:14+00:00

The local variable @cgrp isn't used if !CONFIG_CGROUP_SCHED.  Mark the
variable with __maybe_unused to avoid a compile warning.

Reported-by: "kbuild-all@01.org" 
Signed-off-by: Tejun Heo

cgroup, sched: Move basic cpu stats from cgroup.stat to cpu.stat

2017-10-26T17:56:33+00:00

The basic cpu stat is currently shown with "cpu." prefix in
cgroup.stat, and the same information is duplicated in cpu.stat when
cpu controller is enabled.  This is ugly and not very scalable as we
want to expand the coverage of stat information which is always
available.

This patch makes cgroup core always create "cpu.stat" file and show
the basic cpu stat there and calls the cpu controller to show the
extra stats when enabled.  This ensures that the same information
isn't presented in multiple places and makes future expansion of basic
stats easier.

Signed-off-by: Tejun Heo 
Acked-by: Peter Zijlstra (Intel)

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

2017-10-06T01:19:22+00:00

Just simple overlapping changes.

Signed-off-by: David S. Miller