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 <[email protected]> --- kernel/sched/fair.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- 3.7+git/kernel/sched/fair.c 2012-12-16 16:35:08.724441527 -0800 +++ linux/kernel/sched/fair.c 2012-12-18 21:37:24.727964195 -0800 @@ -793,8 +793,11 @@ unsigned int sysctl_numa_balancing_scan_ 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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
