Re: 4879b7ae05 ("Merge tag 'dmaengine-4.12-rc1' of .."): WARNING: kernel stack regs at bd92bc2e in 01-cpu-hotplug:3811 has bad 'bp' value 000001be

From: Josh Poimboeuf
Date: Mon Oct 02 2017 - 17:31:19 EST


On Mon, Oct 02, 2017 at 04:26:54PM -0500, Josh Poimboeuf wrote:
> Fengguang, assuming it's reliably recreatable, any chance you could
> recreate with the following patch?

Sorry, here's a version which actually compiles.

diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index d145a0b1f529..00234fa5a33a 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -44,7 +44,8 @@ static void unwind_dump(struct unwind_state *state)
state->stack_info.type, state->stack_info.next_sp,
state->stack_mask, state->graph_idx);

- for (sp = state->orig_sp; sp; sp = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
+ for (sp = PTR_ALIGN(state->orig_sp, sizeof(long)); sp;
+ sp = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {
if (get_stack_info(sp, state->task, &stack_info, &visit_mask))
break;