Konstantin Khlebnikov 96b777452d sched/cgroup: Move sched_online_group() back into css_online() to fix crash ...

Commit:

  2f5177f0fd7e ("sched/cgroup: Fix/cleanup cgroup teardown/init")

.. moved sched_online_group() from css_online() to css_alloc().
It exposes half-baked task group into global lists before initializing
generic cgroup stuff.

LTP testcase (third in cgroup_regression_test) written for testing
similar race in kernels 2.6.26-2.6.28 easily triggers this oops:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  IP: kernfs_path_from_node_locked+0x260/0x320
  CPU: 1 PID: 30346 Comm: cat Not tainted 4.10.0-rc5-test #4
  Call Trace:
  ? kernfs_path_from_node+0x4f/0x60
  kernfs_path_from_node+0x3e/0x60
  print_rt_rq+0x44/0x2b0
  print_rt_stats+0x7a/0xd0
  print_cpu+0x2fc/0xe80
  ? __might_sleep+0x4a/0x80
  sched_debug_show+0x17/0x30
  seq_read+0xf2/0x3b0
  proc_reg_read+0x42/0x70
  __vfs_read+0x28/0x130
  ? security_file_permission+0x9b/0xc0
  ? rw_verify_area+0x4e/0xb0
  vfs_read+0xa5/0x170
  SyS_read+0x46/0xa0
  entry_SYSCALL_64_fastpath+0x1e/0xad

Here the task group is already linked into the global RCU-protected 'task_groups'
list, but the css->cgroup pointer is still NULL.

This patch reverts this chunk and moves online back to css_online().

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 2f5177f0fd7e ("sched/cgroup: Fix/cleanup cgroup teardown/init")
Link: http://lkml.kernel.org/r/148655324740.424917.5302984537258726349.stgit@buzz
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2017-02-24 09:25:28 +01:00

..

bpf

bpf: introduce BPF_F_ALLOW_OVERRIDE flag

2017-02-12 21:52:19 -05:00

configs

config: android: enable CONFIG_SECCOMP

2016-10-11 15:06:32 -07:00

debug

kdb: call vkdb_printf() from vprintk_default() only when wanted

2016-12-14 16:04:08 -08:00

events

Linux 4.10-rc8

2017-02-14 07:29:14 +01:00

gcov

gcov: add support for gcc version >= 6

2016-07-15 14:54:27 +09:00

irq

IOMMU Updates for Linux v4.11

2017-02-20 16:42:43 -08:00

livepatch

livepatch/module: make TAINT_LIVEPATCH module-specific

2016-08-26 14:42:08 +02:00

locking

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

2017-02-20 13:23:30 -08:00

power

PM / sleep: Fix test_suspend after sleep state rework

2017-02-18 02:16:27 +01:00

printk

printk: use rcuidle console tracepoint

2017-02-18 17:27:00 -08:00

rcu

Merge branches 'doc.2017.01.15b', 'dyntick.2017.01.23a', 'fixes.2017.01.23a', 'srcu.2017.01.25a' and 'torture.2017.01.15b' into HEAD

2017-01-25 12:56:05 -08:00

sched

sched/cgroup: Move sched_online_group() back into css_online() to fix crash

2017-02-24 09:25:28 +01:00

time

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

2017-02-20 12:52:55 -08:00

trace

tracing/kprobes: Fix __init annotation

2017-02-02 10:48:35 -05:00

.gitignore

…

acct.c

acct: Convert obsolete cputime type to nsecs

2017-02-01 09:13:51 +01:00

async.c

async: export current_is_async()

2015-11-19 17:51:48 +01:00

audit_fsnotify.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2016-12-17 18:44:00 -08:00

audit_tree.c

Merge branch 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit

2017-01-05 23:06:06 -08:00

audit_watch.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2016-12-17 18:44:00 -08:00

audit.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2016-12-17 18:44:00 -08:00

audit.h

audit_log_{name,link_denied}: constify struct path

2016-12-05 19:00:38 -05:00

auditfilter.c

audit: add support for session ID user filter

2016-11-29 15:10:12 -05:00

auditsc.c

Merge branch 'stable-4.10' of git://git.infradead.org/users/pcmoore/audit

2016-12-14 14:06:40 -08:00

backtracetest.c

…

bounds.c

…

capability.c

capability: export has_capability

2017-01-12 07:01:56 -07:00

cgroup_freezer.c

cgroup: kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] and friends

2015-12-03 10:24:08 -05:00

cgroup_pids.c

cgroup: Use lld instead of ld when printing pids controller events_limit

2016-06-21 15:03:36 -04:00

cgroup.c

bpf: introduce BPF_F_ALLOW_OVERRIDE flag

2017-02-12 21:52:19 -05:00

compat.c

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

2016-12-24 11:46:01 -08:00

configs.c

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

2016-12-24 11:46:01 -08:00

context_tracking.c

context_tracking: Switch to new static_branch API

2015-11-24 09:56:43 +01:00

cpu_pm.c

…

cpu.c

cpu/hotplug: Remove unused but set variable in _cpu_down()

2017-01-18 11:55:09 +01:00

cpuset.c

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

2016-12-24 11:46:01 -08:00

crash_dump.c

…

cred.c

cred: Reject inodes with invalid ids in set_create_file_as()

2016-06-30 18:05:09 -05:00

delayacct.c

delaycct: Convert obsolete cputime type to nsecs

2017-02-01 09:13:52 +01:00

dma.c

…

elfcore.c

…

exec_domain.c

…

exit.c

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

2017-02-20 13:23:30 -08:00

extable.c

kprobes, extable: Identify kprobes trampolines as kernel text area

2017-01-14 08:38:05 +01:00

fork.c

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

2017-02-20 13:23:30 -08:00

freezer.c

freezer, oom: check TIF_MEMDIE on the correct task

2016-07-28 16:07:41 -07:00

futex_compat.c

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

2016-12-24 11:46:01 -08:00

futex.c

futex: Move futex_init() to core_initcall

2017-02-13 16:12:22 +01:00

groups.c

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

2016-12-24 11:46:01 -08:00

hung_task.c

hung_task: decrement sysctl_hung_task_warnings only if it is positive

2016-12-12 18:55:09 -08:00

irq_work.c

treewide: Remove old email address

2015-11-23 09:44:58 +01:00

jump_label.c

jump_labels: API for flushing deferred jump label updates

2017-01-12 14:33:16 +01:00

kallsyms.c

kallsyms: add support for relative offsets in kallsyms address table

2016-03-15 16:55:16 -07:00

kcmp.c

ptrace: use fsuid, fsgid, effective creds for fs access checks

2016-01-20 17:09:18 -08:00

Kconfig.freezer

…

Kconfig.hz

…

Kconfig.locks

locking/mutex: Allow MUTEX_SPIN_ON_OWNER when DEBUG_MUTEXES

2016-10-25 11:31:51 +02:00

Kconfig.preempt

…

kcov.c

kcov: make kcov work properly with KASLR enabled

2016-12-20 09:48:47 -08:00

kexec_core.c

kexec: add cond_resched into kimage_alloc_crash_control_pages

2016-12-14 16:04:07 -08:00

kexec_file.c

ima: on soft reboot, save the measurement list

2016-12-20 09:48:44 -08:00

kexec_internal.h

kexec_file: Allow arch-specific memory walking for kexec_add_buffer

2016-11-30 23:14:57 +11:00

kexec.c

kexec: allow architectures to override boot mapping

2016-08-02 19:35:27 -04:00

kmod.c

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

2016-12-24 11:46:01 -08:00

kprobes.c

kprobes, extable: Identify kprobes trampolines as kernel text area

2017-01-14 08:38:05 +01:00

ksysfs.c

kexec: add a kexec_crash_loaded() function

2016-08-02 19:35:30 -04:00

kthread.c

time: Remove CONFIG_TIMER_STATS

2017-02-10 11:15:08 +01:00

latencytop.c

sched/debug: Make schedstats a runtime tunable that is disabled by default

2016-02-09 11:54:23 +01:00

Makefile

Merge branch 'akpm' (patches from Andrew)

2016-12-14 17:25:18 -08:00

membarrier.c

Fix: Disable sys_membarrier when nohz_full is enabled

2017-01-23 11:32:16 -08:00

memremap.c

mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}

2017-01-10 18:31:54 -08:00

module_signing.c

KEYS: Move the point of trust determination to __key_link()

2016-04-11 22:43:43 +01:00

module-internal.h

…

module.c

modversions: treat symbol CRCs as 32 bit quantities

2017-02-03 08:28:25 -08:00

notifier.c

…

nsproxy.c

cgroup: introduce cgroup namespaces

2016-02-16 13:04:58 -05:00

padata.c

padata: Remove unused but set variables

2016-10-25 11:08:10 +08:00

panic.c

kernel/panic.c: add missing \n

2017-01-24 16:26:14 -08:00

params.c

Nothing exciting, minor tweaks and cleanups.

2015-11-09 15:53:39 -08:00

pid_namespace.c

pid: fix lockdep deadlock warning due to ucount_lock

2017-01-10 13:34:56 +13:00

pid.c

locking/atomic, kref: Add KREF_INIT()

2017-01-14 11:37:18 +01:00

profile.c

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

2016-12-24 11:46:01 -08:00

ptrace.c

ptrace: Don't allow accessing an undumpable mm

2016-11-22 12:57:38 -06:00

range.c

…

reboot.c

…

relay.c

relay: check array offset before using it

2016-12-14 16:04:08 -08:00

resource.c

/proc/iomem: only expose physical resource addresses to privileged users

2016-04-14 12:56:09 -07:00

seccomp.c

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

2016-12-14 13:57:44 -08:00

signal.c

signal: Convert obsolete cputime type to nsecs

2017-02-01 09:13:53 +01:00

smp.c

kernel/smp: Tell the user we're bringing up secondary CPUs

2016-10-26 12:02:35 +02:00

smpboot.c

kthread/smpboot: do not park in kthread_create_on_cpu()

2016-10-11 15:06:33 -07:00

smpboot.h

cpu/hotplug: Create hotplug threads

2016-03-01 20:36:56 +01:00

softirq.c

softirq: Display IRQ_POLL for irq-poll statistics

2016-10-21 15:45:47 -06:00

stacktrace.c

stacktrace, lockdep: Fix address, newline ugliness

2017-02-08 08:21:31 +01:00

stop_machine.c

locking/core, stop_machine: Yield the CPU during stop machine()

2016-11-16 10:15:09 +01:00

sys_ni.c

move aio compat to fs/aio.c

2016-12-22 22:58:37 -05:00

sys.c

sched/cputime: Convert task/group cputime to nsecs

2017-02-01 09:13:49 +01:00

sysctl_binary.c

sysctl: add KERN_CONT to deprecated_sysctl_warning()

2016-12-14 16:04:07 -08:00

sysctl.c

sched/rt: Show the 'sched_rr_timeslice' SCHED_RR timeslice tuning knob in milliseconds

2017-02-01 11:01:30 +01:00

task_work.c

task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works

2016-08-02 19:35:02 -04:00

taskstats.c

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

2016-11-15 10:54:36 -05:00

test_kprobes.c

…

torture.c

torture: Convert torture_shutdown() to hrtimer

2016-08-22 10:01:49 -07:00

tracepoint.c

tracing: Have the reg function allow to fail

2016-12-09 09:13:30 -05:00

tsacct.c

tsacct: Convert obsolete cputime type to nsecs

2017-02-01 09:13:52 +01:00

ucount.c

kernel/ucount.c: mark user_header with kmemleak_ignore()

2017-02-08 15:41:43 -08:00

uid16.c

Replace <asm/uaccess.h> with <linux/uaccess.h> globally

2016-12-24 11:46:01 -08:00

up.c

smp: Add function to execute a function synchronously on a CPU

2016-09-05 13:52:39 +02:00

user_namespace.c

Merge branch 'nsfs-ioctls' into HEAD

2016-09-22 20:00:36 -05:00

user-return-notifier.c

…

user.c

…

utsname_sysctl.c

…

utsname.c

Merge branch 'nsfs-ioctls' into HEAD

2016-09-22 20:00:36 -05:00

watchdog_hld.c

kernel/watchdog: prevent false hardlockup on overloaded system

2017-01-24 16:26:14 -08:00

watchdog.c

kernel/watchdog: prevent false hardlockup on overloaded system

2017-01-24 16:26:14 -08:00

workqueue_internal.h

sched/core: Get rid of 'cpu' argument in wq_worker_sleeping()

2016-03-02 10:28:47 -05:00

workqueue.c

time: Remove CONFIG_TIMER_STATS

2017-02-10 11:15:08 +01:00