LoongArch: Check unwind_error() in arch_stack_walk()

We can see the following messages with CONFIG_PROVE_LOCKING=y on
LoongArch:

  BUG: MAX_STACK_TRACE_ENTRIES too low!
  turning off the locking correctness validator.

This is because stack_trace_save() returns a big value after call
arch_stack_walk(), here is the call trace:

  save_trace()
    stack_trace_save()
      arch_stack_walk()
        stack_trace_consume_entry()

arch_stack_walk() should return immediately if unwind_next_frame()
failed, no need to do the useless loops to increase the value of c->len
in stack_trace_consume_entry(), then we can fix the above problem.

Cc: stable@vger.kernel.org
Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/all/8a44ad71-68d2-4926-892f-72bfc7a67e2a@roeck-us.net/
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/loongarch/kernel/stacktrace.c b/arch/loongarch/kernel/stacktrace.c
index 3a690f96f00c..2463d2fea21f 100644
--- a/arch/loongarch/kernel/stacktrace.c
+++ b/arch/loongarch/kernel/stacktrace.c
@@ -30,7 +30,7 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
 
 	regs->regs[1] = 0;
 	for (unwind_start(&state, task, regs);
-	      !unwind_done(&state); unwind_next_frame(&state)) {
+	     !unwind_done(&state) && !unwind_error(&state); unwind_next_frame(&state)) {
 		addr = unwind_get_return_address(&state);
 		if (!addr || !consume_entry(cookie, addr))
 			break;