[stable] [PATCH 1/2] coresight: etb10: Do not call smp_processor_id from preemptible

Sasha Levin sashal at kernel.org
Thu Jan 9 06:35:37 PST 2020


On Wed, Jan 08, 2020 at 11:05:40AM +0000, Suzuki K Poulose wrote:
>[ Upstream commit 730766bae3280a25d40ea76a53dc6342e84e6513 ]
>
>During a perf session we try to allocate buffers on the "node" associated
>with the CPU the event is bound to. If it is not bound to a CPU, we
>use the current CPU node, using smp_processor_id(). However this is unsafe
>in a pre-emptible context and could generate the splats as below :
>
> BUG: using smp_processor_id() in preemptible [00000000] code: perf/2544
>
>Use NUMA_NO_NODE hint instead of using the current node for events
>not bound to CPUs.
>
>Fixes: 2997aa4063d97fdb39 ("coresight: etb10: implementing AUX API")
>Cc: Mathieu Poirier <mathieu.poirier at linaro.org>
>Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
>Cc: stable <stable at vger.kernel.org> # v4.9 to v4.19
>Signed-off-by: Mathieu Poirier <mathieu.poirier at linaro.org>
>Link: https://lore.kernel.org/r/20190620221237.3536-5-mathieu.poirier@linaro.org

I've queued this for 4.9-4.19. There was a simple conflict on 4.9 which
also had to be resolved.

-- 
Thanks,
Sasha



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