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

[Suzuki Kuruppassery Poulose]

On 09/01/2020 14:35, Sasha Levin wrote:
> 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@xxxxxxxxxx>
> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > Cc: stable <stable@xxxxxxxxxxxxxxx> # v4.9 to v4.19
> > Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> > Link: 
> > https://lore.kernel.org/r/20190620221237.3536-5-mathieu.poirier@xxxxxxxxxx 
>
> 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 !

Suzuki