Re: BUG: corrupted list in sctp_association_free

[Neil Horman]

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@xxxxxxxxx> wrote:
> > On Tue, Mar 13, 2018 at 3:34 PM, syzbot
> > <syzbot+e56a5d45f832ef33ad2f@xxxxxxxxxxxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxxxxxxx
> >> 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@xxxxxxxxxxxxxxxxx
> >>
> >> 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

Neil

>