From: Tiezhu Yang yangtiezhu@loongson.cn
commit 370a3b8f58743eceb97c5256538d6048c26d2d03 upstream.
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.ne... Signed-off-by: Tiezhu Yang yangtiezhu@loongson.cn Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/loongarch/kernel/stacktrace.c | 2 +- arch/loongarch/kernel/unwind.c | 1 + arch/loongarch/kernel/unwind_prologue.c | 4 +++- 3 files changed, 5 insertions(+), 2 deletions(-)
--- a/arch/loongarch/kernel/stacktrace.c +++ b/arch/loongarch/kernel/stacktrace.c @@ -30,7 +30,7 @@ void arch_stack_walk(stack_trace_consume
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; --- a/arch/loongarch/kernel/unwind.c +++ b/arch/loongarch/kernel/unwind.c @@ -28,5 +28,6 @@ bool default_next_frame(struct unwind_st
} while (!get_stack_info(state->sp, state->task, info));
+ state->error = true; return false; } --- a/arch/loongarch/kernel/unwind_prologue.c +++ b/arch/loongarch/kernel/unwind_prologue.c @@ -211,7 +211,7 @@ static bool next_frame(struct unwind_sta pc = regs->csr_era;
if (user_mode(regs) || !__kernel_text_address(pc)) - return false; + goto out;
state->first = true; state->pc = pc; @@ -226,6 +226,8 @@ static bool next_frame(struct unwind_sta
} while (!get_stack_info(state->sp, state->task, info));
+out: + state->error = true; return false; }