From 83824639c3ae9f357daf7ac2f8590b46d167296b Mon Sep 17 00:00:00 2001 From: Russ Cox Date: Thu, 4 Sep 2014 23:12:10 -0400 Subject: [PATCH] syscall: in linux/arm Syscall, zero R3, R4, R5 The general kernel system call interface takes 6 arguments: R0, R1, R2, R3, R4, R5. Syscall is for calls that only need 3. The amd64 and 386 versions zero the extra arg registers, but the arm version does not. func utimensat calls Syscall with 3 arguments. The kernel expects a 4th argument. That turns out to be whatever is in R3 at the time of the call. CL 137160043 changed various pieces of code and apparently changed the value left in R3 at the time of utimensat's Syscall. This causes the kernel to return EINVAL. Change linux/arm Syscall to zero R3, R4, R5, so that calls will behave deterministically, even if they pass too few arguments. Arguably, utimensat could be fixed too, but the predictable zeroing is certainly worth doing, and once done utimensat's use of Syscall is fine. Fixes arm build. TBR=bradfitz CC=golang-codereviews https://golang.org/cl/141080043 --- src/pkg/syscall/asm_linux_arm.s | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/pkg/syscall/asm_linux_arm.s b/src/pkg/syscall/asm_linux_arm.s index 014fa618f6..3be0a13e17 100644 --- a/src/pkg/syscall/asm_linux_arm.s +++ b/src/pkg/syscall/asm_linux_arm.s @@ -18,6 +18,9 @@ TEXT ·Syscall(SB),NOSPLIT,$0-28 MOVW 8(SP), R0 MOVW 12(SP), R1 MOVW 16(SP), R2 + MOVW $0, R3 + MOVW $0, R4 + MOVW $0, R5 SWI $0 MOVW $0xfffff001, R1 CMP R1, R0 -- 2.48.1