[PATCH v3 4/4] coresight: etb10: Do not call smp_processor_id from preemptible

From: Suzuki K Poulose
Date: Thu May 30 2019 - 12:58:28 EST


We find the current CPU using smp_processor_id() if the event is not bound
to a CPU, to find the node for memory allocation. Use the safe
numa_node_id() instead, to avoid BUG(). e.g:

BUG: using smp_processor_id() in preemptible [00000000] code: perf/2544

Fixes: 2997aa4063d97fdb39 ("coresight: etb10: implementing AUX API")
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
drivers/hwtracing/coresight/coresight-etb10.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

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)
--
2.7.4