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From:   Eric Dumazet <edumazet@google.com>
Date:   Wed, 29 Jun 2022 19:46:35 +0200
Message-ID: <CANn89iLvG0QBVkdhbC-x59ac=B=j+ZxXitBGanBo+8ThMJGG1g@mail.gmail.com>
Subject: Re: [syzbot] WARNING in sk_stream_kill_queues (8)
To:     syzbot <syzbot+a0e6f8738b58f7654417@syzkaller.appspotmail.com>,
        Stanislav Fomichev <sdf@google.com>,
        Cong Wang <cong.wang@bytedance.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        John Fastabend <john.fastabend@gmail.com>
Cc:     David Miller <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>, Paolo Abeni <pabeni@redhat.com>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        Wei Wang <weiwan@google.com>
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Precedence: bulk

On Wed, Jun 29, 2022 at 7:45 PM Eric Dumazet <edumazet@google.com> wrote:
>
> On Wed, Jun 29, 2022 at 7:41 PM syzbot
> <syzbot+a0e6f8738b58f7654417@syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    aab35c3d5112 Add linux-next specific files for 20220627
> > git tree:       linux-next
> > console+strace: https://syzkaller.appspot.com/x/log.txt?x=126fef90080000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=6a874f114a1e4a6b
> > dashboard link: https://syzkaller.appspot.com/bug?extid=a0e6f8738b58f7654417
> > compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14ae0c98080000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=145124f4080000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+a0e6f8738b58f7654417@syzkaller.appspotmail.com
> >
> > nf_conntrack: default automatic helper assignment has been turned off for security reasons and CT-based firewall rule not found. Use the iptables CT target to attach helpers instead.
> > ------------[ cut here ]------------
> > WARNING: CPU: 1 PID: 3601 at net/core/stream.c:205 sk_stream_kill_queues+0x2ee/0x3d0 net/core/stream.c:205
> > Modules linked in:
> > CPU: 1 PID: 3601 Comm: syz-executor340 Not tainted 5.19.0-rc4-next-20220627-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > RIP: 0010:sk_stream_kill_queues+0x2ee/0x3d0 net/core/stream.c:205
> > Code: 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e ec 00 00 00 8b ab 28 02 00 00 e9 60 ff ff ff e8 3b 9a 29 fa 0f 0b eb 97 e8 32 9a 29 fa <0f> 0b eb a0 e8 29 9a 29 fa 0f 0b e9 6a fe ff ff e8 0d a1 75 fa e9
> > RSP: 0018:ffffc90002e6fbf0 EFLAGS: 00010293
> > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
> > RDX: ffff88801e90ba80 RSI: ffffffff87511cce RDI: 0000000000000005
> > RBP: 0000000000000b00 R08: 0000000000000005 R09: 0000000000000000
> > R10: 0000000000000b00 R11: 0000000000000004 R12: ffff88801e0c8e28
> > R13: ffffffff913121c0 R14: ffff88801e0c8c28 R15: ffff88801e0c8db8
> > FS:  0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
> > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 000000000045b630 CR3: 000000000ba8e000 CR4: 00000000003506e0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > Call Trace:
> >  <TASK>
> >  inet_csk_destroy_sock+0x1a5/0x440 net/ipv4/inet_connection_sock.c:1013
> >  __tcp_close+0xb92/0xf50 net/ipv4/tcp.c:2963
> >  tcp_close+0x29/0xc0 net/ipv4/tcp.c:2975
> >  inet_release+0x12e/0x270 net/ipv4/af_inet.c:428
> >  __sock_release+0xcd/0x280 net/socket.c:650
> >  sock_close+0x18/0x20 net/socket.c:1365
> >  __fput+0x277/0x9d0 fs/file_table.c:317
> >  task_work_run+0xdd/0x1a0 kernel/task_work.c:177
> >  exit_task_work include/linux/task_work.h:38 [inline]
> >  do_exit+0xaf1/0x29f0 kernel/exit.c:795
> >  do_group_exit+0xd2/0x2f0 kernel/exit.c:925
> >  __do_sys_exit_group kernel/exit.c:936 [inline]
> >  __se_sys_exit_group kernel/exit.c:934 [inline]
> >  __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:934
> >  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> >  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> >  entry_SYSCALL_64_after_hwframe+0x46/0xb0
> > RIP: 0033:0x7f080e760989
> > Code: Unable to access opcode bytes at RIP 0x7f080e76095f.
> > RSP: 002b:00007ffcee785818 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
> > RAX: ffffffffffffffda RBX: 00007f080e7d4270 RCX: 00007f080e760989
> > RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
> > RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 0000000000000010
> > R10: 0000000000000010 R11: 0000000000000246 R12: 00007f080e7d4270
> > R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
> >  </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.
> > syzbot can test patches for this issue, for details see:
> > https://goo.gl/tpsmEJ#testing-patches
>
> Stanislav has bisected the issue to:
>
> commit 965b57b469a589d64d81b1688b38dcb537011bb0
> Author: Cong Wang <cong.wang@bytedance.com>
> Date:   Wed Jun 15 09:20:12 2022 -0700
>
>     net: Introduce a new proto_ops ->read_skb()
>
>     Currently both splice() and sockmap use ->read_sock() to
>     read skb from receive queue, but for sockmap we only read
>     one entire skb at a time, so ->read_sock() is too conservative
>     to use. Introduce a new proto_ops ->read_skb() which supports
>     this sematic, with this we can finally pass the ownership of
>     skb to recv actors.
>
>     For non-TCP protocols, all ->read_sock() can be simply
>     converted to ->read_skb().
>
>     Signed-off-by: Cong Wang <cong.wang@bytedance.com>
>     Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
>     Reviewed-by: John Fastabend <john.fastabend@gmail.com>
>     Link: https://lore.kernel.org/bpf/20220615162014.89193-3-xiyou.wangcong@gmail.com

Repro is doing something like:


mmap(0x1ffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
-1, 0) = 0x1ffff000
mmap(0x20000000, 16777216, PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000
mmap(0x21000000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS,
-1, 0) = 0x21000000
socket(AF_INET, SOCK_STREAM, IPPROTO_IP) = 3
bpf(BPF_PROG_LOAD, {prog_type=BPF_PROG_TYPE_SK_SKB, insn_cnt=4,
insns=0x20000040, license="GPL", log_level=4, log_size=64912,
log_buf="", kern_version=KERNEL_VERSION(0, 0, 0), prog_flags=0,
prog_name="", prog_ifindex=0,
expected_attach_type=BPF_CGROUP_INET_INGRESS}, 72) = 4
bpf(BPF_MAP_CREATE, {map_type=BPF_MAP_TYPE_SOCKHASH, key_size=4,
value_size=4, max_entries=18, map_flags=0, inner_map_fd=-1,
map_name="", map_ifindex=0, btf_fd=-1, btf_key_type_id=0,
btf_value_type_id=0, btf_vmlinux_value_type_id=0, map_extra=0}, 72) =
5
bpf(BPF_PROG_ATTACH, {target_fd=5, attach_bpf_fd=4,
attach_type=BPF_SK_SKB_STREAM_VERDICT, attach_flags=0}, 16) = 0
bind(3, {sa_family=AF_INET, sin_port=htons(20000),
sin_addr=inet_addr("224.0.0.2")}, 16) = 0
sendto(3, NULL, 0, MSG_OOB|MSG_SENDPAGE_NOTLAST|MSG_FASTOPEN,
{sa_family=AF_INET, sin_port=htons(20000),
sin_addr=inet_addr("0.0.0.0")}, 16) = 0
bpf(BPF_MAP_UPDATE_ELEM, {map_fd=5, key=0x200002c0, value=0x20000340,
flags=BPF_ANY}, 32) = 0
shutdown(3, SHUT_WR)                    = 0
exit_group(0)                           = ?