livepatch: Use static buffer for debugging messages under rq lock

The err_buf array uses 128 bytes of stack space. Move it off the stack by making it static. It's safe to use a shared buffer because klp_try_switch_task() is called under klp_mutex. Acked-by: Miroslav Benes <[email protected]> Acked-by: Josh Poimboeuf <[email protected]> Reviewed-by: Kamalesh Babulal <[email protected]> Signed-off-by: Petr Mladek <[email protected]>
IreneKnapp · Jun 5, 2019 · f36e664 · f36e664
1 parent 573de2a
commit f36e664
Showing 1 changed file with 1 addition and 2 deletions.
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
@@ -293,11 +293,11 @@ static int klp_check_stack(struct task_struct *task, char *err_buf)
  */
 static bool klp_try_switch_task(struct task_struct *task)
 {
+	static char err_buf[STACK_ERR_BUF_SIZE];
 	struct rq *rq;
 	struct rq_flags flags;
 	int ret;
 	bool success = false;
-	char err_buf[STACK_ERR_BUF_SIZE];
 
 	err_buf[0] = '\0';
 
@@ -340,7 +340,6 @@ static bool klp_try_switch_task(struct task_struct *task)
 		pr_debug("%s", err_buf);
 
 	return success;
-
 }
 
 /*