Messages in this thread Patch in this message | | | Date | Tue, 19 Nov 2013 11:15:33 -0800 | From | tip-bot for Peter Zijlstra <> | Subject | [tip:sched/urgent] sched: Avoid NULL dereference on sd_busy |
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Commit-ID: 42eb088ed246a5a817bb45a8b32fe234cf1c0f8b Gitweb: http://git.kernel.org/tip/42eb088ed246a5a817bb45a8b32fe234cf1c0f8b Author: Peter Zijlstra <peterz@infradead.org> AuthorDate: Tue, 19 Nov 2013 16:41:49 +0100 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Tue, 19 Nov 2013 17:01:16 +0100
sched: Avoid NULL dereference on sd_busy
Commit 37dc6b50cee9 ("sched: Remove unnecessary iteration over sched domains to update nr_busy_cpus") forgot to clear 'sd_busy' under some conditions leading to a possible NULL deref in set_cpu_sd_state_idle().
Reported-by: Anton Blanchard <anton@samba.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131118113701.GF3866@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/sched/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index c180860..a1591ca 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4910,8 +4910,9 @@ static void update_top_cache_domain(int cpu) if (sd) { id = cpumask_first(sched_domain_span(sd)); size = cpumask_weight(sched_domain_span(sd)); - rcu_assign_pointer(per_cpu(sd_busy, cpu), sd->parent); + sd = sd->parent; /* sd_busy */ } + rcu_assign_pointer(per_cpu(sd_busy, cpu), sd); rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); per_cpu(sd_llc_size, cpu) = size;
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