From: syzbot <syzbot+e6300f66a999a6612477@syzkaller.appspotmail.com>
To: andrii@kernel.org, ast@kernel.org, bjorn@kernel.org,
bpf@vger.kernel.org, daniel@iogearbox.net, davem@davemloft.net,
edumazet@google.com, horms@kernel.org, jonathan.lemon@gmail.com,
kuba@kernel.org, linux-kernel@vger.kernel.org,
maciej.fijalkowski@intel.com, magnus.karlsson@intel.com,
netdev@vger.kernel.org, pabeni@redhat.com, sdf@fomichev.me,
syzkaller-bugs@googlegroups.com
Subject: [syzbot] [bpf?] [net?] possible deadlock in xsk_diag_dump (2)
Date: Mon, 04 Aug 2025 09:51:28 -0700 [thread overview]
Message-ID: <6890e510.050a0220.1fc43d.000f.GAE@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: d2eedaa3909b Merge tag 'rtc-6.17' of git://git.kernel.org/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=159482f0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=75e522434dc68cb9
dashboard link: https://syzkaller.appspot.com/bug?extid=e6300f66a999a6612477
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3435b26b899d/disk-d2eedaa3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/531223373575/vmlinux-d2eedaa3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e82f9030b8d5/bzImage-d2eedaa3.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e6300f66a999a6612477@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.16.0-syzkaller-11489-gd2eedaa3909b #0 Not tainted
------------------------------------------------------
syz.8.4735/22857 is trying to acquire lock:
ffff8880223e06b8 (&xs->mutex){+.+.}-{4:4}, at: xsk_diag_fill net/xdp/xsk_diag.c:113 [inline]
ffff8880223e06b8 (&xs->mutex){+.+.}-{4:4}, at: xsk_diag_dump+0x550/0x14d0 net/xdp/xsk_diag.c:166
but task is already holding lock:
ffff888031291c98 (&net->xdp.lock){+.+.}-{4:4}, at: xsk_diag_dump+0x178/0x14d0 net/xdp/xsk_diag.c:158
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&net->xdp.lock){+.+.}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1360 kernel/locking/mutex.c:760
xsk_notifier+0x89/0x230 net/xdp/xsk.c:1664
notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
call_netdevice_notifiers net/core/dev.c:2281 [inline]
unregister_netdevice_many_notify+0x14d7/0x1ff0 net/core/dev.c:12156
unregister_netdevice_many net/core/dev.c:12219 [inline]
unregister_netdevice_queue+0x33c/0x380 net/core/dev.c:12063
register_netdevice+0x1689/0x1ae0 net/core/dev.c:11241
bpq_new_device drivers/net/hamradio/bpqether.c:481 [inline]
bpq_device_event+0x491/0x600 drivers/net/hamradio/bpqether.c:523
notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
call_netdevice_notifiers net/core/dev.c:2281 [inline]
__dev_notify_flags+0x18d/0x2e0 net/core/dev.c:-1
netif_change_flags+0xe8/0x1a0 net/core/dev.c:9608
dev_change_flags+0x130/0x260 net/core/dev_api.c:68
devinet_ioctl+0xbb4/0x1b50 net/ipv4/devinet.c:1200
inet_ioctl+0x3c0/0x4c0 net/ipv4/af_inet.c:1001
sock_do_ioctl+0xdc/0x300 net/socket.c:1238
sock_ioctl+0x576/0x790 net/socket.c:1359
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:598 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:584
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (&dev_instance_lock_key#20){+.+.}-{4:4}:
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1360 kernel/locking/mutex.c:760
netdev_lock include/linux/netdevice.h:2758 [inline]
netdev_lock_ops include/net/netdev_lock.h:42 [inline]
xsk_bind+0x2f7/0xf90 net/xdp/xsk.c:1193
__sys_bind_socket net/socket.c:1858 [inline]
__sys_bind+0x2c6/0x3e0 net/socket.c:1889
__do_sys_bind net/socket.c:1894 [inline]
__se_sys_bind net/socket.c:1892 [inline]
__x64_sys_bind+0x7a/0x90 net/socket.c:1892
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&xs->mutex){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1360 kernel/locking/mutex.c:760
xsk_diag_fill net/xdp/xsk_diag.c:113 [inline]
xsk_diag_dump+0x550/0x14d0 net/xdp/xsk_diag.c:166
netlink_dump+0x6e4/0xe90 net/netlink/af_netlink.c:2327
__netlink_dump_start+0x5cb/0x7e0 net/netlink/af_netlink.c:2442
netlink_dump_start include/linux/netlink.h:341 [inline]
xsk_diag_handler_dump+0x183/0x220 net/xdp/xsk_diag.c:193
sock_diag_rcv_msg+0x4cc/0x600 net/core/sock_diag.c:-1
netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:714 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:729
sock_write_iter+0x258/0x330 net/socket.c:1179
do_iter_readv_writev+0x56e/0x7f0 fs/read_write.c:-1
vfs_writev+0x31a/0x960 fs/read_write.c:1057
do_writev+0x14d/0x2d0 fs/read_write.c:1103
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
other info that might help us debug this:
Chain exists of:
&xs->mutex --> &dev_instance_lock_key#20 --> &net->xdp.lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&net->xdp.lock);
lock(&dev_instance_lock_key#20);
lock(&net->xdp.lock);
lock(&xs->mutex);
*** DEADLOCK ***
2 locks held by syz.8.4735/22857:
#0: ffff8880223e16d0 (nlk_cb_mutex-SOCK_DIAG){+.+.}-{4:4}, at: __netlink_dump_start+0xfe/0x7e0 net/netlink/af_netlink.c:2406
#1: ffff888031291c98 (&net->xdp.lock){+.+.}-{4:4}, at: xsk_diag_dump+0x178/0x14d0 net/xdp/xsk_diag.c:158
stack backtrace:
CPU: 0 UID: 0 PID: 22857 Comm: syz.8.4735 Not tainted 6.16.0-syzkaller-11489-gd2eedaa3909b #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043
check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:598 [inline]
__mutex_lock+0x187/0x1360 kernel/locking/mutex.c:760
xsk_diag_fill net/xdp/xsk_diag.c:113 [inline]
xsk_diag_dump+0x550/0x14d0 net/xdp/xsk_diag.c:166
netlink_dump+0x6e4/0xe90 net/netlink/af_netlink.c:2327
__netlink_dump_start+0x5cb/0x7e0 net/netlink/af_netlink.c:2442
netlink_dump_start include/linux/netlink.h:341 [inline]
xsk_diag_handler_dump+0x183/0x220 net/xdp/xsk_diag.c:193
sock_diag_rcv_msg+0x4cc/0x600 net/core/sock_diag.c:-1
netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:714 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:729
sock_write_iter+0x258/0x330 net/socket.c:1179
do_iter_readv_writev+0x56e/0x7f0 fs/read_write.c:-1
vfs_writev+0x31a/0x960 fs/read_write.c:1057
do_writev+0x14d/0x2d0 fs/read_write.c:1103
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6e7b38eb69
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6e791d5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f6e7b5b6160 RCX: 00007f6e7b38eb69
RDX: 0000000000000001 RSI: 0000200000000140 RDI: 0000000000000007
RBP: 00007f6e7b411df1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f6e7b5b6160 R15: 00007ffdbe0ab9a8
</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
next reply other threads:[~2025-08-04 16:51 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-04 16:51 syzbot [this message]
2025-08-05 17:16 ` [syzbot] [bpf?] [net?] possible deadlock in xsk_diag_dump (2) Stanislav Fomichev
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=6890e510.050a0220.1fc43d.000f.GAE@google.com \
--to=syzbot+e6300f66a999a6612477@syzkaller.appspotmail.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bjorn@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=horms@kernel.org \
--cc=jonathan.lemon@gmail.com \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=maciej.fijalkowski@intel.com \
--cc=magnus.karlsson@intel.com \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=sdf@fomichev.me \
--cc=syzkaller-bugs@googlegroups.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).