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@xxxxxxxxx> --- 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 ddcc350..74fe735 100644 --- a/arch/mips/kernel/ftrace.c +++ b/arch/mips/kernel/ftrace.c @@ -115,11 +115,10 @@ 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 -- 1.8.4.3
