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Bharata B Rao a18b83b7ef cpuacct: make cpuacct hierarchy walk in cpuacct_charge() safe when rcupreempt is used -v2 
Impact: fix cgroups race under rcu-preempt

cpuacct_charge() obtains task's ca and does a hierarchy walk upwards.
This can race with the task's movement between cgroups. This race
can cause an access to freed ca pointer in cpuacct_charge() or access
to invalid cgroups pointer of the task. This will not happen with rcu or
tree rcu as cpuacct_charge() is called with preemption disabled. However if
rcupreempt is used, the race is seen. Thanks to Li Zefan for explaining this.

Fix this race by explicitly protecting ca and the hierarchy walk with
rcu_read_lock().

Changes for v2:

 - Update patch descrition (as per Li Zefan's review comments).

 - Remove comments in cpuacct_charge() which explained why rcu_read_lock()
   was needed (as per Peter Zijlstra's review comments).

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Tested-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
 		2009-03-31 18:27:59 +02:00
..
irq Merge branch 'core/xen' into x86/urgent 2009-02-04 14:54:56 +01:00
power Hibernation: Introduce system_entering_hibernation 2009-01-27 02:15:45 -05:00
time hrtimers: allow the hot-unplugging of all cpus 2009-01-30 22:35:29 +01:00
trace ftrace: do_each_pid_task() needs rcu lock 2009-02-03 22:50:58 +01:00
.gitignore Update kernel/.gitignore with new auto-generated files 2008-02-09 23:27:01 -08:00
Kconfig.freezer container freezer: implement freezer cgroup subsystem 2008-10-20 08:52:34 -07:00
Kconfig.hz sched: fix SCHED_HRTICK dependency 2008-07-28 14:37:38 +02:00
Kconfig.preempt rcu: provide RCU options on non-preempt architectures too 2008-12-25 09:31:28 +01:00
Makefile kernel/up.c: omit it if SMP=y, USE_GENERIC_SMP_HELPERS=n 2009-01-14 09:42:11 -08:00
acct.c [CVE-2009-0029] System call wrappers part 04 2009-01-14 14:15:19 +01:00
async.c kernel/async.c: fix printk warnings 2009-02-05 12:56:46 -08:00
audit.c [PATCH] fix broken timestamps in AVC generated by kernel threads 2008-12-09 02:27:41 -05:00
audit.h fixing audit rule ordering mess, part 1 2009-01-04 15:14:41 -05:00
audit_tree.c audit: validate comparison operations, store them in sane form 2009-01-04 15:14:42 -05:00
auditfilter.c audit: validate comparison operations, store them in sane form 2009-01-04 15:14:42 -05:00
auditsc.c make sure that filterkey of task,always rules is reported 2009-01-04 15:14:42 -05:00
backtracetest.c backtrace: replace timer with tasklet + completions 2008-06-27 18:09:16 +02:00
bounds.c Add kbuild.h that contains common definitions for kbuild users 2008-04-29 08:06:29 -07:00
capability.c [CVE-2009-0029] System call wrappers part 04 2009-01-14 14:15:19 +01:00
cgroup.c cgroup: fix root_count when mount fails due to busy subsystem 2009-01-29 18:04:45 -08:00
cgroup_debug.c cgroups: fix probable race with put_css_set[_taskexit] and find_css_set 2008-10-20 08:52:38 -07:00
cgroup_freezer.c freezer_cg: disable writing freezer.state of root cgroup 2008-11-12 17:17:16 -08:00
compat.c Allow times and time system calls to return small negative values 2009-01-06 15:59:13 -08:00
configs.c kernel/configs.c: remove useless comments 2008-10-20 08:52:34 -07:00
cpu.c stop_machine/cpu hotplug: fix disable_nonboot_cpus 2009-01-07 11:36:14 -08:00
cpuset.c cpuset: fix possible deadlock in async_rebuild_sched_domains 2009-01-19 02:44:00 +01:00
cred-internals.h CRED: Inaugurate COW credentials 2008-11-14 10:39:23 +11:00
cred.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6 2009-01-09 13:59:25 -08:00
delayacct.c schedstat: consolidate per-task cpu runtime stats 2008-12-18 13:54:01 +01:00
dma-coherent.c dma-coherent: Restore dma_alloc_from_coherent() large alloc fall back policy. 2009-01-21 18:51:53 +09:00
dma.c kernel/dma.c: remove a CVS keyword 2008-10-16 11:21:30 -07:00
exec_domain.c [CVE-2009-0029] System call wrappers part 04 2009-01-14 14:15:19 +01:00
exit.c [CVE-2009-0029] System call wrappers part 08 2009-01-14 14:15:21 +01:00
extable.c Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-12-30 16:10:19 -08:00
fork.c fork.c: fix NULL pointer dereference when nr_threads == threads-max 2009-02-06 08:43:11 -08:00
freezer.c freezer_cg: use thaw_process() in unfreeze_cgroup() 2008-10-30 11:38:45 -07:00
futex.c [CVE-2009-0029] System call wrappers part 31 2009-01-14 14:15:31 +01:00
futex_compat.c CRED: Use RCU to access another task's creds and to release a task's own creds 2008-11-14 10:39:19 +11:00
hrtimer.c hrtimer: prevent negative expiry value after clock_was_set() 2009-01-30 22:35:34 +01:00
itimer.c [CVE-2009-0029] System call wrappers part 05 2009-01-14 14:15:20 +01:00
kallsyms.c Revert "kbuild: strip generated symbols from *.ko" 2009-01-14 21:38:20 +01:00
kexec.c [CVE-2009-0029] System call wrappers part 07 2009-01-14 14:15:20 +01:00
kfifo.c
…
kgdb.c kgdb: call touch_softlockup_watchdog on resume 2008-10-06 13:50:59 -05:00
kmod.c kmod: fix varargs kernel-doc 2009-01-06 15:59:27 -08:00
kprobes.c kprobes: check CONFIG_FREEZER instead of CONFIG_PM 2009-01-16 14:32:17 -05:00
ksysfs.c kernel/ksysfs.c:fix dependence on CONFIG_NET 2009-01-06 10:44:31 -08:00
kthread.c tracepoints: add DECLARE_TRACE() and DEFINE_TRACE() 2008-11-16 09:01:36 +01:00
latencytop.c KSYM_SYMBOL_LEN fixes 2008-12-10 08:01:54 -08:00
lockdep.c lockdep: fix deadlock in lockdep_trace_alloc 2009-03-30 23:19:24 +02:00
lockdep_internals.h lockdep: get_user_chars() redo 2009-02-14 23:28:22 +01:00
lockdep_proc.c lockstat: warn about disabled lock debugging 2009-02-14 23:28:28 +01:00
lockdep_states.h lockdep: move state bit definitions around 2009-02-14 23:27:59 +01:00
marker.c markers/tracpoints: fix non-modular build 2008-11-16 09:52:03 +01:00
module.c modules: Use a better scheme for refcounting 2009-02-02 19:17:55 -08:00
mutex-debug.c mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
mutex-debug.h mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
mutex.c mutex: adaptive spinnning, performance tweaks 2009-01-14 19:03:54 +01:00
mutex.h mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
notifier.c Merge commit 'v2.6.28-rc6' into core/debug 2008-11-26 08:22:50 +01:00
ns_cgroup.c ns_cgroup: remove unused spinlock 2009-01-08 08:31:02 -08:00
nsproxy.c User namespaces: set of cleanups (v2) 2008-11-24 18:57:41 -05:00
panic.c oops: increment the oops UUID every time we oops 2009-01-06 15:59:12 -08:00
params.c Fix compile warning in kernel/params.c 2008-10-23 12:09:00 -07:00
pid.c pid: generalize task_active_pid_ns 2009-01-08 08:31:12 -08:00
pid_namespace.c pid_ns: (BUG 11391) change ->child_reaper when init->group_leader exits 2008-09-02 19:21:38 -07:00
pm_qos_params.c pm_qos_requirement might sleep 2008-09-02 19:21:40 -07:00
posix-cpu-timers.c itimers: remove the per-cpu-ish-ness 2009-01-07 18:52:44 +01:00
posix-timers.c [CVE-2009-0029] System call wrappers part 05 2009-01-14 14:15:20 +01:00
printk.c [CVE-2009-0029] System call wrappers part 27 2009-01-14 14:15:29 +01:00
profile.c profile: don't include <asm/ptrace.h> twice. 2009-01-06 15:59:14 -08:00
ptrace.c [CVE-2009-0029] System call wrappers part 27 2009-01-14 14:15:29 +01:00
rcuclassic.c rcu: add __cpuinit to rcu_init_percpu_data() 2009-01-14 11:26:40 +01:00
rcupdate.c rcu: eliminate synchronize_rcu_xxx macro 2009-01-05 10:18:08 +01:00
rcupreempt.c rcu: eliminate synchronize_rcu_xxx macro 2009-01-05 10:18:08 +01:00
rcupreempt_trace.c "Tree RCU": scalable classic RCU implementation 2008-12-18 21:56:04 +01:00
rcutorture.c rcu: fix bug in rcutorture system-shutdown code 2009-01-07 23:36:25 +01:00
rcutree.c rcu: add __cpuinit to rcu_init_percpu_data() 2009-01-14 11:26:40 +01:00
rcutree_trace.c "Tree RCU": scalable classic RCU implementation 2008-12-18 21:56:04 +01:00
relay.c relay: fix lock imbalance in relay_late_setup_files 2009-01-18 20:29:35 +01:00
res_counter.c memcg: memory cgroup resource counters for hierarchy 2009-01-08 08:31:05 -08:00
resource.c resources: fix parameter name and kernel-doc 2009-01-15 16:39:38 -08:00
rtmutex-debug.c Don't operate with pid_t in rtmutex tester 2008-02-08 09:22:41 -08:00
rtmutex-debug.h
…
rtmutex-tester.c sysdev: Pass the attribute to the low level sysdev show/store function 2008-07-21 21:55:02 -07:00
rtmutex.c hrtimer: convert kernel/* to the new hrtimer apis 2008-09-05 21:35:13 -07:00
rtmutex.h
…
rtmutex_common.h Don't operate with pid_t in rtmutex tester 2008-02-08 09:22:41 -08:00
rwsem.c
…
sched.c cpuacct: make cpuacct hierarchy walk in cpuacct_charge() safe when rcupreempt is used -v2 2009-03-31 18:27:59 +02:00
sched_clock.c sched_clock: prevent scd->clock from moving backwards, take #2 2008-12-31 09:53:21 +01:00
sched_cpupri.c sched: fix section mismatch 2009-01-06 11:07:15 +01:00
sched_cpupri.h sched: convert struct cpupri_vec cpumask_var_t. 2008-11-24 17:52:22 +01:00
sched_debug.c sched: partly revert "sched debug: remove NULL checking in print_cfs_rt_rq()" 2009-01-11 02:40:32 +01:00
sched_fair.c sched: fix buddie group latency 2009-02-01 10:49:51 +01:00
sched_features.h mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
sched_idletask.c sched: add CONFIG_SMP consistency 2008-10-22 10:01:52 +02:00
sched_rt.c sched_rt: don't use first_cpu on cpumask created with cpumask_and 2009-02-01 10:49:52 +01:00
sched_stats.h itimers: remove the per-cpu-ish-ness 2009-01-07 18:52:44 +01:00
seccomp.c
…
semaphore.c semaphore: __down_common: use signal_pending_state() 2008-08-05 14:33:47 -07:00
signal.c signals, debug: fix BUG: using smp_processor_id() in preemptible code in print_fatal_signal() 2009-01-27 00:36:19 +01:00
smp.c generic-ipi: use per cpu data for single cpu ipi calls 2009-01-30 18:31:08 +01:00
softirq.c Merge branch 'cpus4096-for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-03 12:04:39 -08:00
softlockup.c softlock: fix false panic which can occur if softlockup_thresh is reduced 2009-01-14 11:48:07 +01:00
spinlock.c lockdep: spin_lock_nest_lock(), checkpatch fixes 2008-08-13 13:56:51 +02:00
srcu.c
…
stacktrace.c stacktrace: provide save_stack_trace_tsk() weak alias 2008-12-25 11:44:43 +01:00
stop_machine.c stop_machine: introduce stop_machine_create/destroy. 2009-01-05 08:40:14 +10:30
sys.c revert "rlimit: permit setting RLIMIT_NOFILE to RLIM_INFINITY" 2009-02-05 12:56:47 -08:00
sys_ni.c [CVE-2009-0029] Make sys_syslog a conditional system call 2009-01-14 14:15:16 +01:00
sysctl.c Merge branch 'core/debugobjects' into core/urgent 2009-01-22 10:03:02 +01:00
sysctl_check.c [XFS] remove restricted chown parameter from xfs linux 2008-10-30 18:30:09 +11:00
taskstats.c cpumask: convert rest of files in kernel/ 2009-01-01 10:12:28 +10:30
test_kprobes.c kprobes: add tests for register_kprobes 2009-01-06 15:59:20 -08:00
time.c [CVE-2009-0029] System call wrappers part 01 2009-01-14 14:15:18 +01:00
timeconst.pl Make constants in kernel/timeconst.h fixed 64 bits 2008-05-02 16:18:42 -07:00
timer.c timer: implement lockdep deadlock detection 2009-02-14 23:25:52 +01:00
tracepoint.c markers/tracpoints: fix non-modular build 2008-11-16 09:52:03 +01:00
tsacct.c mm: introduce get_mm_hiwater_xxx(), fix taskstats->hiwater_xxx accounting 2009-01-06 15:59:09 -08:00
uid16.c [CVE-2009-0029] System call wrappers part 19 2009-01-14 14:15:26 +01:00
up.c smp_call_function_single(): be slightly less stupid, fix #2 2009-01-12 16:04:37 +01:00
user.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-12-28 12:27:58 -08:00
user_namespace.c User namespaces: set of cleanups (v2) 2008-11-24 18:57:41 -05:00
utsname.c removed unused #include <linux/version.h>'s 2008-08-23 12:14:12 -07:00
utsname_sysctl.c sysctl: simplify ->strategy 2008-10-16 11:21:47 -07:00
wait.c wait: prevent exclusive waiter starvation 2009-02-05 12:56:48 -08:00
workqueue.c work_on_cpu: Use our own workqueue. 2009-01-19 22:36:07 +01:00