From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f199.google.com (mail-qt0-f199.google.com [209.85.216.199]) by kanga.kvack.org (Postfix) with ESMTP id B65C36B0365 for ; Tue, 13 Jun 2017 09:01:15 -0400 (EDT) Received: by mail-qt0-f199.google.com with SMTP id x58so63616601qtc.0 for ; Tue, 13 Jun 2017 06:01:15 -0700 (PDT) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com. [45.249.212.188]) by mx.google.com with ESMTPS id v28si11721085qth.285.2017.06.13.06.01.12 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 13 Jun 2017 06:01:13 -0700 (PDT) From: zhong jiang Subject: [PATCH v2] exit: avoid undefined behaviour when call wait4 Date: Tue, 13 Jun 2017 20:53:31 +0800 Message-ID: <1497358411-53071-1-git-send-email-zhongjiang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, jlayton@redhat.com Cc: oleg@redhat.com, jslaby@suse.cz, viro@zeniv.linux.org.uk, mhocko@kernel.org, vbabka@suse.cz, linux-mm@kvack.org, linux-kernel@vger.kernel.org From: zhongjiang wait4(-2147483648, 0x20, 0, 0xdd0000) triggers: UBSAN: Undefined behaviour in kernel/exit.c:1651:9 The related calltrace is as follows: [518871.435738] negation of -2147483648 cannot be represented in type 'int': [518871.442618] CPU: 9 PID: 16482 Comm: zj Tainted: G B ---- ------- 3.10.0-327.53.58.71.x86_64+ #66 [518871.452874] Hardware name: Huawei Technologies Co., Ltd. Tecal RH2285 /BC11BTSA , BIOS CTSAV036 04/27/2011 [518871.464690] ffffffff82599190 000000008b740a25 ffff880112447d90 ffffffff81d6eb16 [518871.472395] ffff880112447da8 ffffffff81d6ebc9 ffffffff82599180 ffff880112447e98 [518871.480101] ffffffff81d6fc99 0000000041b58ab3 ffffffff8228d698 ffffffff81d6fb90 [518871.487801] Call Trace: [518871.490435] [] dump_stack+0x19/0x1b [518871.495751] [] ubsan_epilogue+0xd/0x50 [518871.501328] [] __ubsan_handle_negate_overflow+0x109/0x14e [518871.508548] [] ? __ubsan_handle_divrem_overflow+0x1df/0x1df [518871.516041] [] ? lg_local_lock+0x24/0xb0 [518871.521785] [] ? lg_local_unlock+0x20/0xd0 [518871.527708] [] ? __pmd_alloc+0x180/0x180 [518871.533458] [] ? mntput+0x3b/0x70 [518871.538598] [] SyS_wait4+0x1cb/0x1e0 [518871.543999] [] ? SyS_waitid+0x220/0x220 [518871.549661] [] ? __audit_syscall_entry+0x1f7/0x2a0 [518871.556278] [] system_call_fastpath+0x16/0x1b The patch by excluding the overflow to avoid the UBSAN warning. Signed-off-by: zhong jiang --- kernel/exit.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/exit.c b/kernel/exit.c index 516acdb..cfe70cf 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1701,6 +1701,10 @@ static long do_wait(struct wait_opts *wo) if (upid == -1) type = PIDTYPE_MAX; else if (upid < 0) { + /* -INT_MIN is not defined */ + if (upid == INT_MIN) + return -ESRCH; + type = PIDTYPE_PGID; pid = find_get_pid(-upid); } else if (upid == 0) { -- 1.7.12.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org