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| author | Hugh Dickins <hughd@google.com> | 2012-12-19 17:42:16 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-20 07:06:56 -0800 |
| commit | 2832bc19f6668fd00116f61f821105040599ef8b (patch) | |
| tree | 9839b9321ab7c3dc86f003d69cae522a78d02f20 | |
| parent | cda73a10eb3f493871ed39f468db50a65ebeddce (diff) | |
| download | lwn-2832bc19f6668fd00116f61f821105040599ef8b.tar.gz lwn-2832bc19f6668fd00116f61f821105040599ef8b.zip | |
sched: numa: ksm: fix oops in task_numa_placment()
task_numa_placement() oopsed on NULL p->mm when task_numa_fault() got
called in the handling of break_ksm() for ksmd. That might be a
peculiar case, which perhaps KSM could takes steps to avoid? but it's
more robust if task_numa_placement() allows for such a possibility.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | kernel/sched/fair.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 4603d6cb9e25..5eea8707234a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -793,8 +793,11 @@ unsigned int sysctl_numa_balancing_scan_delay = 1000; static void task_numa_placement(struct task_struct *p) { - int seq = ACCESS_ONCE(p->mm->numa_scan_seq); + int seq; + if (!p->mm) /* for example, ksmd faulting in a user's mm */ + return; + seq = ACCESS_ONCE(p->mm->numa_scan_seq); if (p->numa_scan_seq == seq) return; p->numa_scan_seq = seq; |