optee: fix uninited async notif value

BugLink: https://bugs.launchpad.net/bugs/2028979

commit 654d031 upstream.

Fixes an uninitialized variable in irq_handler() that could lead to
unpredictable behavior in case OP-TEE fails to handle SMC function ID
OPTEE_SMC_GET_ASYNC_NOTIF_VALUE. This change ensures that in that case
get_async_notif_value() properly reports there are no notification
event.

Reported-by: kernel test robot <[email protected]>
Link: https://lore.kernel.org/r/[email protected]/
Reported-by: Dan Carpenter <[email protected]>
Link: https://lore.kernel.org/all/[email protected]/
Fixes: 6749e69 ("optee: add asynchronous notifications")
Signed-off-by: Etienne Carriere <[email protected]>
Reviewed-by: Sumit Garg <[email protected]>
Signed-off-by: Jens Wiklander <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
Signed-off-by: Stefan Bader <[email protected]>

Author: etienne-lms

drivers/tee/optee/smc_abi.c

@@ -984,8 +984,10 @@ static u32 get_async_notif_value(optee_invoke_fn *invoke_fn, bool *value_valid,
 
 	invoke_fn(OPTEE_SMC_GET_ASYNC_NOTIF_VALUE, 0, 0, 0, 0, 0, 0, 0, &res);
 
-	if (res.a0)
+	if (res.a0) {
+		*value_valid = false;
 		return 0;
+	}
 	*value_valid = (res.a2 & OPTEE_SMC_ASYNC_NOTIF_VALUE_VALID);
 	*value_pending = (res.a2 & OPTEE_SMC_ASYNC_NOTIF_VALUE_PENDING);
 	return res.a1;