From mboxrd@z Thu Jan 1 00:00:00 1970 From: syzbot Subject: KMSAN: uninit-value in __dev_mc_add Date: Wed, 26 Sep 2018 07:24:02 -0700 Message-ID: <0000000000005e2e530576c6f9ce@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes To: davem@davemloft.net, edumazet@google.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, sunlw.fnst@cn.fujitsu.com, syzkaller-bugs@googlegroups.com Return-path: Received: from mail-it1-f199.google.com ([209.85.166.199]:58382 "EHLO mail-it1-f199.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727017AbeIZUhP (ORCPT ); Wed, 26 Sep 2018 16:37:15 -0400 Received: by mail-it1-f199.google.com with SMTP id d194-v6so3437104itb.8 for ; Wed, 26 Sep 2018 07:24:03 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: Hello, syzbot found the following crash on: HEAD commit: eb2e67596de2 kmsan: minor code cleanup git tree: https://github.com/google/kmsan.git/master console output: https://syzkaller.appspot.com/x/log.txt?x=136e3b11400000 kernel config: https://syzkaller.appspot.com/x/.config?x=94a9ed72288f7fef dashboard link: https://syzkaller.appspot.com/bug?extid=001516d86dbe88862cec compiler: clang version 8.0.0 (trunk 339414) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+001516d86dbe88862cec@syzkaller.appspotmail.com ================================================================== BUG: KMSAN: uninit-value in memcmp+0x11d/0x180 lib/string.c:863 CPU: 0 PID: 14033 Comm: kworker/0:3 Not tainted 4.19.0-rc4+ #58 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x2f6/0x430 lib/dump_stack.c:113 kmsan_report+0x183/0x2b0 mm/kmsan/kmsan.c:917 __msan_warning+0x70/0xc0 mm/kmsan/kmsan_instr.c:500 memcmp+0x11d/0x180 lib/string.c:863 __hw_addr_add_ex net/core/dev_addr_lists.c:61 [inline] __dev_mc_add+0x215/0x8c0 net/core/dev_addr_lists.c:670 dev_mc_add+0x6d/0x80 net/core/dev_addr_lists.c:687 igmp6_group_added+0x2c8/0xaa0 net/ipv6/mcast.c:676 __ipv6_dev_mc_inc+0xf4b/0x1270 net/ipv6/mcast.c:934 ipv6_dev_mc_inc+0x70/0x80 net/ipv6/mcast.c:941 addrconf_join_solict net/ipv6/addrconf.c:2098 [inline] addrconf_dad_begin net/ipv6/addrconf.c:3879 [inline] addrconf_dad_work+0x437/0x29b0 net/ipv6/addrconf.c:4006 process_one_work+0x197f/0x2490 kernel/workqueue.c:2153 worker_thread+0x1f6a/0x2b00 kernel/workqueue.c:2296 kthread+0x59c/0x5d0 kernel/kthread.c:247 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:416 Local variable description: ----buf@igmp6_group_added Variable was created at: igmp6_group_added+0x46/0xaa0 net/ipv6/mcast.c:664 __ipv6_dev_mc_inc+0xf4b/0x1270 net/ipv6/mcast.c:934 ================================================================== --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot.