[PATCH 4/4] x86/unwind: Disable unwinder warnings on 32-bit

[Josh Poimboeuf]

x86-32 doesn't have stack validation, so in most cases it doesn't make
sense to warn about bad frame pointers.

Reported-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
 arch/x86/kernel/unwind_frame.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index 81aca077fbb6..3dc26f95d46e 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -355,6 +355,13 @@ bool unwind_next_frame(struct unwind_state *state)
 	    state->regs->sp < (unsigned long)task_pt_regs(state->task))
 		goto the_end;
 
+	/*
+	 * There are some known frame pointer issues on 32-bit.  Disable
+	 * unwinder warnings on 32-bit until it gets objtool support.
+	 */
+	if (IS_ENABLED(CONFIG_X86_32))
+		goto the_end;
+
 	if (state->regs) {
 		printk_deferred_once(KERN_WARNING
 			"WARNING: kernel stack regs at %p in %s:%d has bad 'bp' value %p\n",
-- 
2.13.6