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coresight: etb10: Do not call smp_processor_id from preemptible

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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: 2997aa4063 ("coresight: etb10: implementing AUX API")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: stable <stable@vger.kernel.org> # 4.6+
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20190620221237.3536-5-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Suzuki K Poulose 2019-06-20 16:12:36 -06:00 committed by Greg Kroah-Hartman
parent 024c1fd9db
commit 730766bae3
1 changed files with 2 additions and 4 deletions
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6
drivers/hwtracing/coresight/coresight-etb10.c
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@ -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)