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From: Kuniyuki Iwashima <kuniyu@amazon.com>
To: <edumazet@google.com>
CC: <davem@davemloft.net>, <dsahern@kernel.org>, <kuba@kernel.org>,
	<kuniyu@amazon.com>, <linux-kernel@vger.kernel.org>,
	<netdev@vger.kernel.org>, <pabeni@redhat.com>,
	<syzbot+12c506c1aae251e70449@syzkaller.appspotmail.com>,
	<syzkaller-bugs@googlegroups.com>
Subject: Re: [syzbot] [net?] WARNING in sk_nulls_del_node_init_rcu
Date: Fri, 8 Mar 2024 10:03:39 -0800
Message-ID: <20240308180339.53907-1-kuniyu@amazon.com>
In-Reply-To: <CANn89iKXHAoJqVkxSGtFep3Ww+A-v9NeExzgfTKubVo7wYX7_Q@mail.gmail.com>
References: <CANn89iKXHAoJqVkxSGtFep3Ww+A-v9NeExzgfTKubVo7wYX7_Q@mail.gmail.com>
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From: Eric Dumazet <edumazet@google.com>
Date: Fri, 8 Mar 2024 18:36:45 +0100
> On Fri, Mar 8, 2024 at 6:34 PM 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=16aa17f2180000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=fad652894fc96962
> > dashboard link: https://syzkaller.appspot.com/bug?extid=12c506c1aae251e70449
> > compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> >
> > Unfortunately, I don't have any reproducer for this issue yet.
> >
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/c39eb6fb3ad1/disk-c055fc00.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/110f1226eb89/vmlinux-c055fc00.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/1303e2df5cc4/bzImage-c055fc00.xz
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > 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_init_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-00159-gc055fc00c07b #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 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 41 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:0000000000000000
> > 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 f7 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().

I'll look into it.

Thanks!