linux-kernel - [PATCH v3 4/4] coresight: etb10: Do not call smp_processor

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Message-Id: <1559235267-25232-5-git-send-email-suzuki.poulose@arm.com>
Date:   Thu, 30 May 2019 17:54:27 +0100
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, coresight@...ts.linaro.org,
        mathieu.poirier@...aro.org, robin.murphy@....com,
        Suzuki K Poulose <suzuki.poulose@....com>
Subject: [PATCH v3 4/4] coresight: etb10: Do not call smp_processor_id from preemptible

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@...aro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
---
 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