Messages in this thread Patch in this message | | | Date | Wed, 27 Nov 2013 14:22:43 +0100 | From | Peter Zijlstra <> | Subject | Re: [BUG] in sched fair on v3.13-rc1+ doing hotplug |
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On Wed, Nov 27, 2013 at 08:13:45AM -0500, Steven Rostedt wrote: > atomic_inc(&sd->groups->sgp->nr_busy_cpus); <<---- BUG > unlock: > rcu_read_unlock(); > }
tip/sched/urgent has this one:
--- commit 42eb088ed246a5a817bb45a8b32fe234cf1c0f8b Author: Peter Zijlstra <peterz@infradead.org> Date: Tue Nov 19 16:41:49 2013 +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>
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index c1808606ee5f..a1591ca7eb5a 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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