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From: Eric Dumazet <edumazet@google.com>
Date: Fri, 8 Mar 2024 18:36:45 +0100
Message-ID: <CANn89iKXHAoJqVkxSGtFep3Ww+A-v9NeExzgfTKubVo7wYX7_Q@mail.gmail.com>
Subject: Re: [syzbot] [net?] WARNING in sk_nulls_del_node_init_rcu
To: syzbot <syzbot+12c506c1aae251e70449@syzkaller.appspotmail.com>, 
	Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: davem@davemloft.net, dsahern@kernel.org, kuba@kernel.org, 
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, 
	syzkaller-bugs@googlegroups.com
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On Fri, Mar 8, 2024 at 6:34=E2=80=AFPM syzbot
<syzbot+12c506c1aae251e70449@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    c055fc00c07b net/rds: fix WARNING in rds_conn_connect_if_=
d..
> git tree:       net
> console output: https://syzkaller.appspot.com/x/log.txt?x=3D16aa17f218000=
0
> kernel config:  https://syzkaller.appspot.com/x/.config?x=3Dfad652894fc96=
962
> dashboard link: https://syzkaller.appspot.com/bug?extid=3D12c506c1aae251e=
70449
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Deb=
ian) 2.40
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/c39eb6fb3ad1/dis=
k-c055fc00.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/110f1226eb89/vmlinu=
x-c055fc00.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/1303e2df5cc4/b=
zImage-c055fc00.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the comm=
it:
> Reported-by: syzbot+12c506c1aae251e70449@syzkaller.appspotmail.com
>
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
> R13: 000000000000000b R14: 00007f3b817abf80 R15: 00007ffd3beb57b8
>  </TASK>
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 23948 at include/net/sock.h:799 sk_nulls_del_node_in=
it_rcu+0x166/0x1a0 include/net/sock.h:799
> Modules linked in:
> CPU: 0 PID: 23948 Comm: syz-executor.2 Not tainted 6.8.0-rc6-syzkaller-00=
159-gc055fc00c07b #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS G=
oogle 01/25/2024
> RIP: 0010:sk_nulls_del_node_init_rcu+0x166/0x1a0 include/net/sock.h:799
> Code: e8 7f 71 c6 f7 83 fb 02 7c 25 e8 35 6d c6 f7 4d 85 f6 0f 95 c0 5b 4=
1 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc e8 1b 6d c6 f7 90 <0f> 0b 90 eb b2=
 e8 10 6d c6 f7 4c 89 e7 be 04 00 00 00 e8 63 e7 d2
> RSP: 0018:ffffc900032d7848 EFLAGS: 00010246
> RAX: ffffffff89cd0035 RBX: 0000000000000001 RCX: 0000000000040000
> RDX: ffffc90004de1000 RSI: 000000000003ffff RDI: 0000000000040000
> RBP: 1ffff1100439ac26 R08: ffffffff89ccffe3 R09: 1ffff1100439ac28
> R10: dffffc0000000000 R11: ffffed100439ac29 R12: ffff888021cd6140
> R13: dffffc0000000000 R14: ffff88802a9bf5c0 R15: ffff888021cd6130
> FS:  00007f3b823f16c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000=
000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f3b823f0ff8 CR3: 000000004674a000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  __inet_hash_connect+0x140f/0x20b0 net/ipv4/inet_hashtables.c:1139
>  dccp_v6_connect+0xcb9/0x1480 net/dccp/ipv6.c:956
>  __inet_stream_connect+0x262/0xf30 net/ipv4/af_inet.c:678
>  inet_stream_connect+0x65/0xa0 net/ipv4/af_inet.c:749
>  __sys_connect_file net/socket.c:2048 [inline]
>  __sys_connect+0x2df/0x310 net/socket.c:2065
>  __do_sys_connect net/socket.c:2075 [inline]
>  __se_sys_connect net/socket.c:2072 [inline]
>  __x64_sys_connect+0x7a/0x90 net/socket.c:2072
>  do_syscall_64+0xf9/0x240
>  entry_SYSCALL_64_after_hwframe+0x6f/0x77
> RIP: 0033:0x7f3b8167dda9
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f=
7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff=
 ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f3b823f10c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
> RAX: ffffffffffffffda RBX: 00007f3b817abf80 RCX: 00007f3b8167dda9
> RDX: 000000000000001c RSI: 0000000020000040 RDI: 0000000000000003
> RBP: 00007f3b823f1120 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
> R13: 000000000000000b R14: 00007f3b817abf80 R15: 00007ffd3beb57b8
>  </TASK>
>
>
> ---
> This report 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 issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup

CC Kuniyuki, because this is probably caused by

commit 66b60b0c8c4a163b022a9f0ad6769b0fd3dc662f
Author: Kuniyuki Iwashima <kuniyu@amazon.com>
Date:   Wed Feb 14 11:13:08 2024 -0800

    dccp/tcp: Unhash sk from ehash for tb2 alloc failure after
check_estalblished().