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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Sun, 1 Apr 2018 12:29:03 +0200
Message-ID: <CACT4Y+ZhZw+dKrbM2k_25R1_suNbYSmzDcaVLd8znsMEY_1AJA@mail.gmail.com>
Subject: Re: BUG: corrupted list in sctp_association_free
To:     Neil Horman <nhorman@tuxdriver.com>
Cc:     Xin Long <lucien.xin@gmail.com>,
        syzbot <syzbot+e56a5d45f832ef33ad2f@syzkaller.appspotmail.com>,
        davem <davem@davemloft.net>, LKML <linux-kernel@vger.kernel.org>,
        linux-sctp@vger.kernel.org, network dev <netdev@vger.kernel.org>,
        syzkaller-bugs@googlegroups.com,
        Vlad Yasevich <vyasevich@gmail.com>
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On Tue, Mar 13, 2018 at 12:12 PM, Neil Horman <nhorman@tuxdriver.com> wrote:
> On Tue, Mar 13, 2018 at 02:09:09PM +0300, Dmitry Vyukov wrote:
>> On Tue, Mar 13, 2018 at 1:44 PM, Xin Long <lucien.xin@gmail.com> wrote:
>> > On Tue, Mar 13, 2018 at 3:34 PM, syzbot
>> > <syzbot+e56a5d45f832ef33ad2f@syzkaller.appspotmail.com> wrote:
>> >> Hello,
>> >>
>> >> syzbot hit the following crash on net-next commit
>> >> fd372a7a9e5e9d8011a0222d10edd3523abcd3b1 (Thu Mar 8 19:43:48 2018 +0000)
>> >> Merge tag 'mlx5-updates-2018-02-28-2' of
>> >> git://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux
>> >>
>> >> Unfortunately, I don't have any reproducer for this crash yet.
>> >> Raw console output is attached.
>> >> compiler: gcc (GCC) 7.1.1 20170620
>> >> .config is attached.
>> >>
>> >> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> >> Reported-by: syzbot+e56a5d45f832ef33ad2f@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.
>> >>
>> >> selinux_nlmsg_perm: 1 callbacks suppressed
>> >> SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0
>> >> sclass=netlink_route_socket pig=12502 comm=syz-executor3
>> >> SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0
>> >> sclass=netlink_route_socket pig=12528 comm=syz-executor3
>> >> list_del corruption, 00000000fcc5fb27->next is LIST_POISON1
>> >> (00000000cb16e51d)
>> >> ------------[ cut here ]------------
>> >> kernel BUG at lib/list_debug.c:47!
>> >> invalid opcode: 0000 [#1] SMP KASAN
>> >> Dumping ftrace buffer:
>> >>    (ftrace buffer empty)
>> >> Modules linked in:
>> >> CPU: 0 PID: 12537 Comm: syz-executor2 Not tainted 4.16.0-rc4+ #258
>> >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> >> Google 01/01/2011
>> >> RIP: 0010:__list_del_entry_valid+0xd3/0x150 lib/list_debug.c:45
>> >> RSP: 0018:ffff8801b6387778 EFLAGS: 00010286
>> >> RAX: 000000000000004e RBX: dead000000000200 RCX: 0000000000000000
>> >> RDX: 000000000000004e RSI: ffffc90002ed6000 RDI: ffffed0036c70ee3
>> >> RBP: ffff8801b6387790 R08: 1ffff10036c70e3b R09: 0000000000000000
>> >> R10: 0000000000000000 R11: 0000000000000000 R12: dead000000000100
>> >> R13: ffff8801d3164000 R14: ffff8801d8502220 R15: ffff8801b6387c58
>> >> FS:  00007ff42042f700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
>> >> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> >> CR2: 00007ff42040ddb8 CR3: 00000001bd840003 CR4: 00000000001606f0
>> >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> >> Call Trace:
>> >>  __list_del_entry include/linux/list.h:117 [inline]
>> >>  list_del include/linux/list.h:125 [inline]
>> >>  sctp_association_free+0x133/0x930 net/sctp/associola.c:341
>> >>  sctp_sendmsg+0xc67/0x1a80 net/sctp/socket.c:2075
>> >>  inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
>> >>  sock_sendmsg_nosec net/socket.c:629 [inline]
>> >>  sock_sendmsg+0xca/0x110 net/socket.c:639
>> >>  SYSC_sendto+0x361/0x5c0 net/socket.c:1748
>> >>  SyS_sendto+0x40/0x50 net/socket.c:1716
>> >>  do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
>> >>  entry_SYSCALL_64_after_hwframe+0x42/0xb7
>> >> RIP: 0033:0x453e69
>> >> RSP: 002b:00007ff42042ec68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
>> >> RAX: ffffffffffffffda RBX: 00007ff42042f6d4 RCX: 0000000000453e69
>> >> RDX: 0000000000000001 RSI: 0000000020000340 RDI: 0000000000000015
>> >> RBP: 000000000072c0c8 R08: 00000000204d9000 R09: 000000000000001c
>> >> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
>> >> R13: 00000000000004cd R14: 00000000006f73d8 R15: 0000000000000003
>> >> Code: 8f 00 00 00 49 8b 54 24 08 48 39 f2 75 3b 48 83 c4 08 b8 01 00 00 00
>> >> 5b 41 5c 5d c3 4c 89 e2 48 c7 c7 c0 7c 40 86 e8 75 f6 fb fe <0f> 0b 48 c7 c7
>> >> 20 7d 40 86 e8 67 f6 fb fe 0f 0b 48 c7 c7 80 7d
>> >> RIP: __list_del_entry_valid+0xd3/0x150 lib/list_debug.c:45 RSP:
>> >> ffff8801b6387778
>> >> ---[ end trace a6b157f61f9bd43a ]---
>> >> Kernel panic - not syncing: Fatal exception
>> >> Dumping ftrace buffer:
>> >>    (ftrace buffer empty)
>> >> Kernel Offset: disabled
>> >> Rebooting in 86400 seconds..
>> >>
>> >>
>> >> ---
>> >> 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
>> >> 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.
>> > I'd think the patch Neil just posted would fix it.
>>
>>
>> Hi Xin,
>>
>> Could you point me to that commit? We need to tell syzbot about it.
>>
>> Thanks
> Its not been pulled in yet, but this is the email thread:
> https://marc.info/?l=linux-netdev&m=152093814606747&w=2
>
> I agree this patch should fix the crash syzbot noted


#syz fix: sctp: fix error return code in sctp_sendmsg_new_asoc()