coresight: trbe: Return NULL pointer for allocation failures

When the TRBE driver fails to allocate a buffer, it currently returns
the error code "-ENOMEM". However, the caller etm_setup_aux() only
checks for a NULL pointer, so it misses the error. As a result, the
driver continues and eventually causes a kernel panic.

Fix this by returning a NULL pointer from arm_trbe_alloc_buffer() on
allocation failures. This allows that the callers can properly handle
the failure.

Fixes: 3fbf7f011f24 ("coresight: sink: Add TRBE driver")
Reported-by: Tamas Zsoldos <tamas.zsoldos@arm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20250904-cs_etm_auxsetup_fix_error_handling-v2-1-a502d0bafb95@arm.com

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 10f3fb401edf6a00b24b38cdaa7c2865e7a191ac..8f9bbef71f236b327d35a288689df9b0dd8ff3f4 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -748,12 +748,12 @@ static void *arm_trbe_alloc_buffer(struct coresight_device *csdev,
 
        buf = kzalloc_node(sizeof(*buf), GFP_KERNEL, trbe_alloc_node(event));
        if (!buf)
-               return ERR_PTR(-ENOMEM);
+               return NULL;
 
        pglist = kcalloc(nr_pages, sizeof(*pglist), GFP_KERNEL);
        if (!pglist) {
                kfree(buf);
-               return ERR_PTR(-ENOMEM);
+               return NULL;
        }
 
        for (i = 0; i < nr_pages; i++)
@@ -763,7 +763,7 @@ static void *arm_trbe_alloc_buffer(struct coresight_device *csdev,
        if (!buf->trbe_base) {
                kfree(pglist);
                kfree(buf);
-               return ERR_PTR(-ENOMEM);
+               return NULL;
        }
        buf->trbe_limit = buf->trbe_base + nr_pages * PAGE_SIZE;
        buf->trbe_write = buf->trbe_base;