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authorPeter Zijlstra <peterz@infradead.org>2015-11-25 16:02:07 +0100
committerIngo Molnar <mingo@kernel.org>2016-01-06 11:01:07 +0100
commitbe958bdc96f18bc1356177bbb79d46ea0c037b96 (patch)
treedea9e48ddcca9e6fb5d244485a900bfa5b1391f6
parent570f52412ae9432c56897472791ea8db420cbaf1 (diff)
downloadleg-kernel-be958bdc96f18bc1356177bbb79d46ea0c037b96.tar.gz
sched/core: Fix unserialized r-m-w scribbling stuff
Some of the sched bitfieds (notably sched_reset_on_fork) can be set on other than current, this can cause the r-m-w to race with other updates. Since all the sched bits are serialized by scheduler locks, pull them in a separate word. Reported-by: Tejun Heo <tj@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: hannes@cmpxchg.org Cc: mhocko@kernel.org Cc: vdavydov@parallels.com Link: http://lkml.kernel.org/r/20151125150207.GM11639@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--include/linux/sched.h11
1 files changed, 6 insertions, 5 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 9cf9dd1c4cbe..fa39434e3fdd 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1455,14 +1455,15 @@ struct task_struct {
/* Used for emulating ABI behavior of previous Linux versions */
unsigned int personality;
- unsigned in_execve:1; /* Tell the LSMs that the process is doing an
- * execve */
- unsigned in_iowait:1;
-
- /* Revert to default priority/policy when forking */
+ /* scheduler bits, serialized by scheduler locks */
unsigned sched_reset_on_fork:1;
unsigned sched_contributes_to_load:1;
unsigned sched_migrated:1;
+ unsigned :0; /* force alignment to the next boundary */
+
+ /* unserialized, strictly 'current' */
+ unsigned in_execve:1; /* bit to tell LSMs we're in execve */
+ unsigned in_iowait:1;
#ifdef CONFIG_MEMCG
unsigned memcg_may_oom:1;
#endif