| Message ID | 1559837807-15447-5-git-send-email-suzuki.poulose@arm.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 730766bae3280a25d40ea76a53dc6342e84e6513 |
| Headers | show |
| Series | coresight: Do not call smp_processor_id from pre-emptible contexts | expand |
diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c index d5b9ede..3810290 100644 --- a/drivers/hwtracing/coresight/coresight-etb10.c +++ b/drivers/hwtracing/coresight/coresight-etb10.c @@ -374,12 +374,10 @@ static void *etb_alloc_buffer(struct coresight_device *csdev, struct perf_event *event, void **pages, int nr_pages, bool overwrite) { - int node, cpu = event->cpu; + int node; struct cs_buffers *buf; - if (cpu == -1) - cpu = smp_processor_id(); - node = cpu_to_node(cpu); + node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu); buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node); if (!buf)
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@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- drivers/hwtracing/coresight/coresight-etb10.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)