The patch titled
account_group_exec_runtime: fix the racy usage of ->signal
has been removed from the -mm tree. Its filename was
account_group_exec_runtime-fix-the-racy-usage-of-signal.patch
This patch was dropped because whoops
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: account_group_exec_runtime: fix the racy usage of ->signal
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Unlike other similar routines, account_group_exec_runtime() could be
called "implicitly" after exit_notify(). This means we can race with
the parent doing release_task(), we can't just check ->signal != NULL.
Take ->siglock to make sure ->signal can't go away.
This is the minimal fix, with this patch we don't need need get/put cpu,
and I think we should uninline this function.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/sched_stats.h | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff -puN kernel/sched_stats.h~account_group_exec_runtime-fix-the-racy-usage-of-signal kernel/sched_stats.h
--- a/kernel/sched_stats.h~account_group_exec_runtime-fix-the-racy-usage-of-signal
+++ a/kernel/sched_stats.h
@@ -351,10 +351,12 @@ static inline void account_group_exec_ru
unsigned long long ns)
{
struct signal_struct *sig;
+ unsigned long flags;
- sig = tsk->signal;
- if (unlikely(!sig))
+ if (unlikely(!lock_task_sighand(tsk, &flags)))
return;
+
+ sig = tsk->signal;
if (sig->cputime.totals) {
struct task_cputime *times;
@@ -362,4 +364,6 @@ static inline void account_group_exec_ru
times->sum_exec_runtime += ns;
put_cpu_no_resched();
}
+
+ unlock_task_sighand(tsk, &flags);
}
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
account_group_exec_runtime-fix-the-racy-usage-of-signal.patch
forkc-cleanup-for-copy_sighand.patch
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