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: [email protected]
Reported-by: Guenter Roeck <[email protected]>
Link: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Tiezhu Yang <[email protected]>
Signed-off-by: Huacai Chen <[email protected]>

0 files changed, 0 insertions, 0 deletions