kernel_optimize_test/kernel
Konstantin Khlebnikov 40af1bbdca mm: correctly synchronize rss-counters at exit/exec
mm->rss_stat counters have per-task delta: task->rss_stat.  Before
changing task->mm pointer the kernel must flush this delta with
sync_mm_rss().

do_exit() already calls sync_mm_rss() to flush the rss-counters before
committing the rss statistics into task->signal->maxrss, taskstats,
audit and other stuff.  Unfortunately the kernel does this before
calling mm_release(), which can call put_user() for processing
task->clear_child_tid.  So at this point we can trigger page-faults and
task->rss_stat becomes non-zero again.  As a result mm->rss_stat becomes
inconsistent and check_mm() will print something like this:

| BUG: Bad rss-counter state mm:ffff88020813c380 idx:1 val:-1
| BUG: Bad rss-counter state mm:ffff88020813c380 idx:2 val:1

This patch moves sync_mm_rss() into mm_release(), and moves mm_release()
out of do_exit() and calls it earlier.  After mm_release() there should
be no pagefaults.

[akpm@linux-foundation.org: tweak comment]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>		[3.4.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-07 14:43:55 -07:00
..
debug
events
gcov
irq Merge branches 'irq-urgent-for-linus' and 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-06-04 11:36:51 -07:00
power
sched
time Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-06-05 09:47:15 -07:00
trace
.gitignore
acct.c
async.c
audit_tree.c
audit_watch.c
audit.c
audit.h
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
cgroup_freezer.c
cgroup.c Merge branch 'for-3.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2012-06-05 11:54:12 -07:00
compat.c
configs.c
cpu_pm.c kernel/cpu_pm.c: fix various typos 2012-05-31 17:49:27 -07:00
cpu.c kernel/cpu.c: document clear_tasks_mm_cpumask() 2012-05-31 17:49:30 -07:00
cpuset.c
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c mm: correctly synchronize rss-counters at exit/exec 2012-06-07 14:43:55 -07:00
extable.c
fork.c mm: correctly synchronize rss-counters at exit/exec 2012-06-07 14:43:55 -07:00
freezer.c
futex_compat.c
futex.c
groups.c
hrtimer.c
hung_task.c
irq_work.c
itimer.c
jump_label.c
kallsyms.c
kcmp.c syscalls, x86: add __NR_kcmp syscall 2012-05-31 17:49:32 -07:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c
kfifo.c
kmod.c kmod.c: fix kernel-doc warning 2012-05-31 17:49:28 -07:00
kprobes.c
ksysfs.c
kthread.c
latencytop.c
lglock.c
lockdep_internals.h
lockdep_proc.c
lockdep_states.h
lockdep.c
Makefile Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-06-01 10:34:35 -07:00
module.c
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid_namespace.c sysctl: make kernel.ns_last_pid control dependent on CHECKPOINT_RESTORE 2012-05-31 17:49:32 -07:00
pid.c
posix-cpu-timers.c
posix-timers.c
printk.c
profile.c
ptrace.c
range.c
rcu.h
rcupdate.c
rcutiny_plugin.h
rcutiny.c
rcutorture.c
rcutree_plugin.h
rcutree_trace.c
rcutree.c
rcutree.h
relay.c
res_counter.c
resource.c kernel/resource.c: correct the comment of allocate_resource() 2012-05-31 17:49:26 -07:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rwsem.c
seccomp.c
semaphore.c
signal.c new helper: signal_delivered() 2012-06-01 12:58:52 -04:00
smp.c
smpboot.c
smpboot.h
softirq.c
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys_ni.c syscalls, x86: add __NR_kcmp syscall 2012-05-31 17:49:32 -07:00
sys.c c/r: prctl: drop VMA flags test on PR_SET_MM_ stack data assignment 2012-06-07 14:43:55 -07:00
sysctl_binary.c
sysctl.c
task_work.c
taskstats.c
test_kprobes.c
time.c
timeconst.pl
timer.c
tracepoint.c
tsacct.c
uid16.c
up.c
user_namespace.c
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
wait.c
watchdog.c
workqueue_sched.h
workqueue.c