From: Ronald Wahl <ronald.wahl@xxxxxxxxxxx>
I encountered a crash on ARM32 when trying to dump the stack of some
zombie process. This is caused by a missing check whether the task
actually has a valid stack. This commit adds this check.
Commit 214d8ca6ee85 ("stacktrace: Provide common infrastructure")
introduced this check for platforms that define CONFIG_ARCH_STACKWALK
but ARM32 is not one of them.
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
Signed-off-by: Ronald Wahl <ronald.wahl@xxxxxxxxxxx>
---
V2: - added missing put_task_stack(task) to avoid memory leak
kernel/stacktrace.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index 9ed5ce989415..0bb67bd633c6 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -298,7 +298,11 @@ unsigned int stack_trace_save_tsk(struct task_struct *task,
.skip = skipnr + (current == task),
};
+ if (!try_get_task_stack(task))
+ return 0;
+
save_stack_trace_tsk(task, &trace);
+ put_task_stack(task);
return trace.nr_entries;
}
--
2.43.0
