From a4671094227d11985c06ee1178d7205c5fd39f8a Mon Sep 17 00:00:00 2001 From: Viller Hsiao <villerhsiao@gmail.com> Date: Sat, 22 Feb 2014 15:46:49 +0800 Subject: [PATCH] MIPS: ftrace: Fix icache flush range error In 32-bit mode, the start address passed to flush_icache_range is shifted by 4 bytes before the second safe_store_code() call. This causes system crash from time to time because the first 4 bytes might not be flushed properly. This bug exists since linux-3.8. Also remove obsoleted comment while at it. Signed-off-by: Viller Hsiao <villerhsiao@gmail.com> Cc: linux-mips@linux-mips.org Cc: rostedt@goodmis.org Cc: fweisbec@gmail.com Cc: mingo@redhat.com Cc: Qais.Yousef@imgtec.com Patchwork: https://patchwork.linux-mips.org/patch/6586/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> --- arch/mips/kernel/ftrace.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c index 185ba258361b..374ed74cd516 100644 --- a/arch/mips/kernel/ftrace.c +++ b/arch/mips/kernel/ftrace.c @@ -111,11 +111,10 @@ static int ftrace_modify_code_2(unsigned long ip, unsigned int new_code1, safe_store_code(new_code1, ip, faulted); if (unlikely(faulted)) return -EFAULT; - ip += 4; - safe_store_code(new_code2, ip, faulted); + safe_store_code(new_code2, ip + 4, faulted); if (unlikely(faulted)) return -EFAULT; - flush_icache_range(ip, ip + 8); /* original ip + 12 */ + flush_icache_range(ip, ip + 8); return 0; } #endif