| From 730766bae3280a25d40ea76a53dc6342e84e6513 Mon Sep 17 00:00:00 2001 |
| From: Suzuki K Poulose <suzuki.poulose@arm.com> |
| Date: Thu, 20 Jun 2019 16:12:36 -0600 |
| Subject: coresight: etb10: Do not call smp_processor_id from preemptible |
| |
| From: Suzuki K Poulose <suzuki.poulose@arm.com> |
| |
| 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 <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> |
| |
| |
| --- |
| drivers/hwtracing/coresight/coresight-etb10.c | 4 +--- |
| 1 file changed, 1 insertion(+), 3 deletions(-) |
| |
| --- a/drivers/hwtracing/coresight/coresight-etb10.c |
| +++ b/drivers/hwtracing/coresight/coresight-etb10.c |
| @@ -279,9 +279,7 @@ static void *etb_alloc_buffer(struct cor |
| 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) |