[PATCH v2 04/23] coresight: trbe: Check the buffer association before IRQ validation

[Leo Yan]

is_perf_trbe() obtains the sink buffer from the output handle and
dereferences buf->cpudata before validating either pointer. A live AUX
transaction does not guarantee that the selected buffer has a CPU
association.

Reject a missing buffer or CPU association before reading CPU driver
data or checking the hardware buffer addresses. Treat these configurations
as an invalid perf TRBE session.

Signed-off-by: Leo Yan <leo.yan at arm.com>
---
 drivers/hwtracing/coresight/coresight-trbe.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 8ec0b4c4987f25d10ee0b2f80c27e10f76357387..91fbdbad3676ffae399df0b4d4ddcd603a40e86c 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -1111,10 +1111,16 @@ static int trbe_handle_overflow(struct perf_output_handle *handle)
 static bool is_perf_trbe(struct perf_output_handle *handle)
 {
 	struct trbe_buf *buf = etm_perf_sink_config(handle);
-	struct trbe_cpudata *cpudata = buf->cpudata;
-	struct trbe_drvdata *drvdata = cpudata->drvdata;
+	struct trbe_cpudata *cpudata;
+	struct trbe_drvdata *drvdata;
 	int cpu = smp_processor_id();
 
+	if (!buf || !buf->cpudata)
+		return false;
+
+	cpudata = buf->cpudata;
+	drvdata = cpudata->drvdata;
+
 	WARN_ON(buf->trbe_hw_base != get_trbe_base_pointer());
 	WARN_ON(buf->trbe_limit != get_trbe_limit_pointer());
 

-- 
2.34.1