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Message-Id: <20201028174301.15033-1-mike.leach@linaro.org>
Date: Wed, 28 Oct 2020 17:43:01 +0000
From: Mike Leach <mike.leach@...aro.org>
To: linux-arm-kernel@...ts.infradead.org, coresight@...ts.linaro.org,
mathieu.poirier@...aro.org, linux-kernel@...r.kernel.org
Cc: suzuki.poulose@....com, alexander.shishkin@...ux.intel.com,
lcherian@...vell.com, Mike Leach <mike.leach@...aro.org>
Subject: [PATCH] coresight: Fix uninitialised pointer bug in etm_setup_aux()
Commit [bb1860efc817] changed the sink handling code introducing an
uninitialised pointer bug. This results in the default sink selection
failing.
Prior to commit:
static void etm_setup_aux(...)
<snip>
struct coresight_device *sink;
<snip>
/* First get the selected sink from user space. */
if (event->attr.config2) {
id = (u32)event->attr.config2;
sink = coresight_get_sink_by_id(id);
} else {
sink = coresight_get_enabled_sink(true);
}
<ctd>
*sink always initialised - possibly to NULL which triggers the
automatic sink selection.
After commit:
static void etm_setup_aux(...)
<snip>
struct coresight_device *sink;
<snip>
/* First get the selected sink from user space. */
if (event->attr.config2) {
id = (u32)event->attr.config2;
sink = coresight_get_sink_by_id(id);
}
<ctd>
*sink pointer uninitialised when not providing a sink on the perf command
line. This breaks later checks to enable automatic sink selection.
Fixes [bb1860efc817] ("coresight: etm: perf: Sink selection using sysfs is deprecated")
Signed-off-by: Mike Leach <mike.leach@...aro.org>
---
drivers/hwtracing/coresight/coresight-etm-perf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index c2c9b127d074..bdc34ca449f7 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -210,7 +210,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
u32 id;
int cpu = event->cpu;
cpumask_t *mask;
- struct coresight_device *sink;
+ struct coresight_device *sink = NULL;
struct etm_event_data *event_data = NULL;
event_data = alloc_event_data(cpu);
--
2.17.1
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