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| author | Peter Zijlstra <peterz@infradead.org> | 2014-02-28 13:39:05 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-03-11 11:33:47 +0100 |
| commit | 177c53d943368fc97644ebc0a250dc8e2d124250 (patch) | |
| tree | b36cfaeb80c11a76daea39f9613c21e2348816a1 /kernel/stop_machine.c | |
| parent | d44753b843e093f9e1f2f14806fbe106fff74898 (diff) | |
| download | lwn-177c53d943368fc97644ebc0a250dc8e2d124250.tar.gz lwn-177c53d943368fc97644ebc0a250dc8e2d124250.zip | |
stop_machine: Fix^2 race between stop_two_cpus() and stop_cpus()
We must use smp_call_function_single(.wait=1) for the
irq_cpu_stop_queue_work() to ensure the queueing is actually done under
stop_cpus_lock. Without this we could have dropped the lock by the time
we do the queueing and get the race we tried to fix.
Fixes: 7053ea1a34fa ("stop_machine: Fix race between stop_two_cpus() and stop_cpus()")
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140228123905.GK3104@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/stop_machine.c')
| -rw-r--r-- | kernel/stop_machine.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index 84571e09c907..01fbae5b97b7 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -293,7 +293,7 @@ int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void * */ smp_call_function_single(min(cpu1, cpu2), &irq_cpu_stop_queue_work, - &call_args, 0); + &call_args, 1); lg_local_unlock(&stop_cpus_lock); preempt_enable(); |