Re: WARNING in inet_sock_destruct

[Paolo Abeni]

Hello,

On Fri, 2022-07-22 at 08:22 -0700, Dipanjan Das wrote:
> We would like to report the following bug which has been found by our
> modified version of syzkaller.
> 
> ======================================================
> description: WARNING in inet_sock_destruct
> affected file: net/ipv4/af_inet.c
> kernel version: 5.19-rc6
> kernel commit: 32346491ddf24599decca06190ebca03ff9de7f8
> git tree: upstream
> kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=cd73026ceaed1402
> crash reproducer: attached
> ======================================================
> Crash log:
> ======================================================
> WARNING: CPU: 1 PID: 10818 at net/ipv4/af_inet.c:153
> inet_sock_destruct+0x6d0/0x8e0 net/ipv4/af_inet.c:153
> Modules linked in: uio_ivshmem(OE) uio(E)
> CPU: 1 PID: 10818 Comm: kworker/1:16 Tainted: G           OE
> 5.19.0-rc6-g2eae0556bb9d #2
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> 1.13.0-1ubuntu1.1 04/01/2014
> Workqueue: events mptcp_worker
> RIP: 0010:inet_sock_destruct+0x6d0/0x8e0 net/ipv4/af_inet.c:153
> Code: 21 02 00 00 41 8b 9c 24 28 02 00 00 e9 07 ff ff ff e8 34 4d 91
> f9 89 ee 4c 89 e7 e8 4a 47 60 ff e9 a6 fc ff ff e8 20 4d 91 f9 <0f> 0b
> e9 84 fe ff ff e8 14 4d 91 f9 0f 0b e9 d4 fd ff ff e8 08 4d
> RSP: 0018:ffffc9001b35fa78 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: 00000000002879d0 RCX: ffff8881326f3b00
> RDX: 0000000000000000 RSI: ffff8881326f3b00 RDI: 0000000000000002
> RBP: ffff888179662674 R08: ffffffff87e983a0 R09: 0000000000000000
> R10: 0000000000000005 R11: 00000000000004ea R12: ffff888179662400
> R13: ffff888179662428 R14: 0000000000000001 R15: ffff88817e38e258
> FS:  0000000000000000(0000) GS:ffff8881f5f00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000020007bc0 CR3: 0000000179592000 CR4: 0000000000150ee0
> Call Trace:
>  <TASK>
>  __sk_destruct+0x4f/0x8e0 net/core/sock.c:2067
>  sk_destruct+0xbd/0xe0 net/core/sock.c:2112
>  __sk_free+0xef/0x3d0 net/core/sock.c:2123
>  sk_free+0x78/0xa0 net/core/sock.c:2134
>  sock_put include/net/sock.h:1927 [inline]
>  __mptcp_close_ssk+0x50f/0x780 net/mptcp/protocol.c:2351
>  __mptcp_destroy_sock+0x332/0x760 net/mptcp/protocol.c:2828
>  mptcp_worker+0x5d2/0xc90 net/mptcp/protocol.c:2586
>  process_one_work+0x9cc/0x1650 kernel/workqueue.c:2289
>  worker_thread+0x623/0x1070 kernel/workqueue.c:2436
>  kthread+0x2e9/0x3a0 kernel/kthread.c:376
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
>  </TASK>

It looks like this is an mptcp-specific issue. I'll try to cook a
patch. Please cc (also) the mptcp ML for this kind (you see and mptcp-
related symbol into the stack trace) of reports, thanks!

Paolo