From mboxrd@z Thu Jan 1 00:00:00 1970 From: syzbot Subject: KMSAN: uninit-value in strnlen Date: Mon, 23 Apr 2018 01:23:01 -0700 Message-ID: <00000000000003f2d5056a7fbf92@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes To: linux-kernel@vger.kernel.org, mostrows@earthlink.net, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com Return-path: Received: from mail-io0-f197.google.com ([209.85.223.197]:54378 "EHLO mail-io0-f197.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754293AbeDWIXC (ORCPT ); Mon, 23 Apr 2018 04:23:02 -0400 Received: by mail-io0-f197.google.com with SMTP id x7-v6so13659629iob.21 for ; Mon, 23 Apr 2018 01:23:02 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: Hello, syzbot hit the following crash on https://github.com/google/kmsan.git/master commit a7f95e9c8a95e9fbb388c3999b61a17667cd3bbe (Sat Apr 21 13:50:22 2018 +0000) kmsan: disable assembly checksums syzbot dashboard link: https://syzkaller.appspot.com/bug?extid=cd06c321e7147d03a65e So far this crash happened 5 times on https://github.com/google/kmsan.git/master. C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5785171018121216 syzkaller reproducer: https://syzkaller.appspot.com/x/repro.syz?id=5117671628603392 Raw console output: https://syzkaller.appspot.com/x/log.txt?id=6310764688179200 Kernel config: https://syzkaller.appspot.com/x/.config?id=328654897048964367 compiler: clang version 7.0.0 (trunk 329391) IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+cd06c321e7147d03a65e@syzkaller.appspotmail.com It will help syzbot understand when the bug is fixed. See footer for details. If you forward the report, please keep this part and the footer. ================================================================== BUG: KMSAN: uninit-value in strnlen+0xc4/0x110 lib/string.c:499 CPU: 1 PID: 4507 Comm: syzkaller579712 Not tainted 4.16.0+ #85 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683 strnlen+0xc4/0x110 lib/string.c:499 dev_name_hash net/core/dev.c:209 [inline] dev_get_by_name_rcu net/core/dev.c:764 [inline] dev_get_by_name+0x6e/0x350 net/core/dev.c:791 pppoe_connect+0xcb7/0x2360 drivers/net/ppp/pppoe.c:665 SYSC_connect+0x41a/0x510 net/socket.c:1639 SyS_connect+0x54/0x80 net/socket.c:1620 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x43fcf9 RSP: 002b:00007ffca4bd4978 EFLAGS: 00000213 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fcf9 RDX: 0000000000000007 RSI: 0000000020000040 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000004002c8 R11: 0000000000000213 R12: 0000000000401620 R13: 00000000004016b0 R14: 0000000000000000 R15: 0000000000000000 Local variable description: ----address@SYSC_connect Variable was created at: SYSC_connect+0x6f/0x510 net/socket.c:1622 SyS_connect+0x54/0x80 net/socket.c:1620 ================================================================== --- This bug is generated by a dumb bot. It may contain errors. See https://goo.gl/tpsmEJ for details. Direct all questions to syzkaller@googlegroups.com. syzbot will keep track of this bug report. If you forgot to add the Reported-by tag, once the fix for this bug is merged into any tree, please reply to this email with: #syz fix: exact-commit-title If you want to test a patch for this bug, please reply with: #syz test: git://repo/address.git branch and provide the patch inline or as an attachment. To mark this as a duplicate of another syzbot report, please reply with: #syz dup: exact-subject-of-another-report If it's a one-off invalid bug report, please reply with: #syz invalid Note: if the crash happens again, it will cause creation of a new bug report. Note: all commands must start from beginning of the line in the email body.