[PATCH] x86/mm: avoid false-positive objtool warning in page_fault_oops()
From: Arnd Bergmann
Date: Tue Dec 17 2024 - 03:31:36 EST
From: Arnd Bergmann <arnd@xxxxxxxx>
When printing the oops for a VMAP_STACK overflow, the final call
frompage_fault_oops() does not return to the original stack, which
confuses gcc, and the unreachable() annotation leads to the end
of the function just continuing on in the next one:
arch/x86/mm/fault.o: warning: objtool: page_fault_oops() falls through to next function kernelmode_fixup_or_oops.constprop.0()
To work around the warning, add an explicit endless loop here that
objtool can detect.
Fixes: 6271cfdfc0e4 ("x86/mm: Improve stack-overflow #PF handling")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
I'm not sure about this one, maybe there is a way for objtool to
detect this and not warn?
---
arch/x86/mm/fault.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index e6c469b323cc..0ef6e3cc54d2 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -678,7 +678,7 @@ page_fault_oops(struct pt_regs *regs, unsigned long error_code,
ASM_CALL_ARG3,
, [arg1] "r" (regs), [arg2] "r" (address), [arg3] "r" (&info));
- unreachable();
+ do { } while (1); /* unreachable */
}
#endif
--
2.39.5