From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751605AbdFEM6u (ORCPT ); Mon, 5 Jun 2017 08:58:50 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:6868 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751354AbdFEM6s (ORCPT ); Mon, 5 Jun 2017 08:58:48 -0400 From: zhongjiang To: CC: , , , , , , Subject: [PATCH v2] signal: Avoid undefined behaviour in kill_something_info Date: Mon, 5 Jun 2017 20:53:27 +0800 Message-ID: <1496667207-56723-1-git-send-email-zhongjiang@huawei.com> X-Mailer: git-send-email 1.7.12.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.175.102.37] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020206.59355584.0170,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 30e31a4175401472831240b8c4bac282 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org when I run the kill(72057458746458112, 0) in the userspace, I hit the following issue. [ 304.606353] UBSAN: Undefined behaviour in kernel/signal.c:1462:11 [ 304.612622] negation of -2147483648 cannot be represented in type 'int': [ 304.619516] CPU: 226 PID: 9849 Comm: test Tainted: G B ---- ------- 3.10.0-327.53.58.70.x86_64_ubsan+ #116 [ 304.630692] Hardware name: Huawei Technologies Co., Ltd. RH8100 V3/BC61PBIA, BIOS BLHSV028 11/11/2014 [ 304.640168] ffffffff825ded30 000000005dc276fa ffff883c3a4b7ce0 ffffffff81d6eb06 [ 304.647870] ffff883c3a4b7cf8 ffffffff81d6ebb9 ffffffff825ded20 ffff883c3a4b7de8 [ 304.655584] ffffffff81d6fc89 0000000041b58ab3 ffffffff8228d6d8 ffffffff81d6fb80 [ 304.663299] Call Trace: [ 304.665827] [] dump_stack+0x19/0x1b [ 304.671115] [] ubsan_epilogue+0xd/0x50 [ 304.676668] [] __ubsan_handle_negate_overflow+0x109/0x14e [ 304.683917] [] ? __ubsan_handle_divrem_overflow+0x1df/0x1df [ 304.691353] [] ? __inc_zone_state+0x29/0xf0 [ 304.697358] [] ? __lru_cache_add+0x8f/0xe0 [ 304.703272] [] ? lru_cache_add+0xe/0x10 [ 304.708921] [] ? map_id_up+0xad/0xe0 [ 304.714306] [] SYSC_kill+0x43e/0x4d0 [ 304.725359] [] ? lg_local_unlock+0x20/0xd0 [ 304.736978] [] ? kill_pid+0x20/0x20 [ 304.747928] [] ? __pmd_alloc+0x180/0x180 [ 304.759273] [] ? mntput+0x3b/0x70 [ 304.769919] [] ? __do_page_fault+0x2bc/0x650 [ 304.781462] [] ? __audit_syscall_entry+0x1f7/0x2a0 [ 304.793476] [] SyS_kill+0xe/0x10 [ 304.803859] [] system_call_fastpath+0x16/0x1b The patch add particular case to avoid the UBSAN detection. Signed-off-by: zhongjiang --- kernel/signal.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/signal.c b/kernel/signal.c index ca92bcf..63148f7 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1395,6 +1395,12 @@ static int kill_something_info(int sig, struct siginfo *info, pid_t pid) read_lock(&tasklist_lock); if (pid != -1) { + /* + * -INT_MIN is undefined, it need to exclude following case to + * avoid the UBSAN detection. + */ + if (pid == INT_MIN) + return -ESRCH; ret = __kill_pgrp_info(sig, info, pid ? find_vpid(-pid) : task_pgrp(current)); } else { -- 1.7.12.4