From: Kees Cook Date: Wed, 13 Jul 2022 21:38:19 +0000 (-0700) Subject: x86/alternative: Report missing return thunk details X-Git-Tag: v5.10.134~9 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=c0a3a9eb262a5e86a36fd5fc4f9fc38470713f13;p=users%2Fdwmw2%2Flinux.git x86/alternative: Report missing return thunk details commit 65cdf0d623bedf0e069bb64ed52e8bb20105e2ba upstream. Debugging missing return thunks is easier if we can see where they're happening. Suggested-by: Peter Zijlstra Signed-off-by: Kees Cook Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/lkml/Ys66hwtFcGbYmoiZ@hirez.programming.kicks-ass.net/ Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 77eefa0b0f324..a85fb17f11804 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -709,7 +709,9 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end) dest = addr + insn.length + insn.immediate.value; if (__static_call_fixup(addr, op, dest) || - WARN_ON_ONCE(dest != &__x86_return_thunk)) + WARN_ONCE(dest != &__x86_return_thunk, + "missing return thunk: %pS-%pS: %*ph", + addr, dest, 5, addr)) continue; DPRINTK("return thunk at: %pS (%px) len: %d to: %pS",