firmware: qcom: scm: fix a NULL-pointer dereference

From: Bartosz Golaszewski <[email protected]>

Some SCM calls can be invoked with __scm being NULL (the driver may not have been and will not be probed as there's no SCM entry in device-tree). Make sure we don't dereference a NULL pointer.

Fixes 449d0d84bcd8 ("firmware: qcom: scm: smc: switch to using the SCM allocator")

Reported-by Rudraksha Gupta <[email protected]>

Closes https://lore.kernel.org/lkml/[email protected]/ open here

Reviewed-by Konrad Dybcio <[email protected]>

Tested-by Rudraksha Gupta <[email protected]>

Reviewed-by Dmitry Baryshkov <[email protected]>

Reviewed-by Stephan Gerhold <[email protected]>

Signed-off-by Bartosz Golaszewski <[email protected]>

---
I dropped patch 2/2 and am resending this separately rebased on top of v6.12-rc1.

 drivers/firmware/qcom/qcom_scm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/firmware/qcom/qcom_scm.c +1 -1

index 10986cb11ec0..8bac4915c211 100644
@@ -216,7 +216,7 @@ static DEFINE_SPINLOCK(scm_query_lock);
 
 struct qcom_tzmem_pool *qcom_scm_get_tzmem_pool(void)
 {
-	return __scm->mempool;
+	return __scm ? __scm->mempool : NULL;
 }
 
 static enum qcom_scm_convention __get_convention(void)

Some SCM calls can be invoked with __scm being NULL (the driver may not have been and will not be probed as there's no SCM entry in device-tree). Make sure we don't dereference a NULL pointer.