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

Greg KH gregkh at linuxfoundation.org
Wed Jan 15 09:21:26 PST 2020


On Wed, Jan 15, 2020 at 04:44:29PM +0000, Suzuki Kuruppassery Poulose wrote:
> 
> Hi Greg,
> 
> On 15/01/2020 15:11, Greg KH wrote:
> > On Thu, Jan 09, 2020 at 02:36:17PM +0000, Suzuki Kuruppassery Poulose wrote:
> > > 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 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 !
> > 
> > Note, these had to all be dropped as they broke the build :(
> > 
> > So can you please send us patches that at least build?  :)
> > 
> 
> Do you have a build failure log ? I did build test it before sending it
> over. I tried it again on 4.9, 4.14 and 4.19. I don't hit any build
> failures here.
> 
> Please could you share the log if you have it handy ?

It was in the stable -rc review emails, I don't have it handy, sorry.

greg k-h



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