From: Suzuki K Poulose Date: Thu, 20 Jun 2019 22:12:36 +0000 (-0600) Subject: coresight: etb10: Do not call smp_processor_id from preemptible X-Git-Tag: v4.9.212~9 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=93897ce10d934f3d5819a7fa10b926f4cf67845f;p=thirdparty%2Fkernel%2Fstable.git coresight: etb10: Do not call smp_processor_id from preemptible commit 730766bae3280a25d40ea76a53dc6342e84e6513 upstream. 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 Signed-off-by: Suzuki K Poulose Cc: stable # 4.6+ Signed-off-by: Mathieu Poirier Link: https://lore.kernel.org/r/20190620221237.3536-5-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c index ace55385b26f9..ff10deed3fdef 100644 --- a/drivers/hwtracing/coresight/coresight-etb10.c +++ b/drivers/hwtracing/coresight/coresight-etb10.c @@ -279,9 +279,7 @@ static void *etb_alloc_buffer(struct coresight_device *csdev, int cpu, int node; struct cs_buffers *buf; - if (cpu == -1) - cpu = smp_processor_id(); - node = cpu_to_node(cpu); + node = (cpu == -1) ? NUMA_NO_NODE : cpu_to_node(cpu); buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node); if (!buf)