From 69e1634985f8d839f74f342925bd7546faea0a19 Mon Sep 17 00:00:00 2001 From: Keith Randall Date: Thu, 2 Feb 2017 18:50:45 -0800 Subject: [PATCH] runtime: darwin/amd64, don't depend on outarg slots being unmodified sigtramp was calling sigtrampgo and depending on the fact that the 3rd argument slot will not be modified on return. Our calling convention doesn't guarantee that. Avoid that assumption. There's no actual bug here, as sigtrampgo does not in fact modify its argument slots. But I found this while working on the dead stack slot clobbering tool. https://go-review.googlesource.com/c/23924/ Change-Id: Ia7e791a2b4c1c74fff24cba8169e7840b4b06ffc Reviewed-on: https://go-review.googlesource.com/36216 Run-TryBot: Keith Randall TryBot-Result: Gobot Gobot Reviewed-by: Ian Lance Taylor --- src/runtime/sys_darwin_amd64.s | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/src/runtime/sys_darwin_amd64.s b/src/runtime/sys_darwin_amd64.s index e68dafe6a6..f94482856c 100644 --- a/src/runtime/sys_darwin_amd64.s +++ b/src/runtime/sys_darwin_amd64.s @@ -252,14 +252,15 @@ TEXT runtime·sigfwd(SB),NOSPLIT,$0-32 POPQ BP RET -TEXT runtime·sigtramp(SB),NOSPLIT,$32 +TEXT runtime·sigtramp(SB),NOSPLIT,$40 MOVL SI, 24(SP) // save infostyle for sigreturn below + MOVQ R8, 32(SP) // save ctx MOVL DX, 0(SP) // sig MOVQ CX, 8(SP) // info MOVQ R8, 16(SP) // ctx MOVQ $runtime·sigtrampgo(SB), AX CALL AX - MOVQ 16(SP), DI // ctx + MOVQ 32(SP), DI // ctx MOVL 24(SP), SI // infostyle MOVL $(0x2000000+184), AX SYSCALL -- 2.50.0