From: syzbot <syzbot+1b20ba3b6d47543a7742@syzkaller.appspotmail.com>
To: johannes@sipsolutions.net, linux-kernel@vger.kernel.org,
linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
syzkaller-bugs@googlegroups.com
Subject: [syzbot] [wireless?] possible deadlock in ieee80211_change_mac (4)
Date: Thu, 26 Feb 2026 22:40:25 -0800 [thread overview]
Message-ID: <69a13c59.050a0220.3a55be.0015.GAE@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: d4f687fbbce4 ovpn: tcp - fix packet extraction from stream
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=1763544a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=665cbf0979cda6c5
dashboard link: https://syzkaller.appspot.com/bug?extid=1b20ba3b6d47543a7742
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ee42a61b2ee7/disk-d4f687fb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e5470ff18ff8/vmlinux-d4f687fb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d50957aaabf2/bzImage-d4f687fb.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1b20ba3b6d47543a7742@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.4107/21056 is trying to acquire lock:
ffff888055af0788 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6441 [inline]
ffff888055af0788 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: ieee80211_change_mac+0xb5/0x1410 net/mac80211/iface.c:324
but task is already holding lock:
ffffffff8fbc12b0 (dev_addr_sem){++++}-{4:4}, at: do_setlink+0x806/0x4590 net/core/rtnetlink.c:3105
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (dev_addr_sem){++++}-{4:4}:
down_read+0x47/0x2e0 kernel/locking/rwsem.c:1537
address_show+0x25/0x250 net/core/net-sysfs.c:266
dev_attr_show+0x58/0xc0 drivers/base/core.c:2421
sysfs_kf_seq_show+0x310/0x490 fs/sysfs/file.c:65
seq_read_iter+0x4ef/0xe10 fs/seq_file.c:231
new_sync_read fs/read_write.c:493 [inline]
vfs_read+0x582/0xa70 fs/read_write.c:574
ksys_read+0x150/0x270 fs/read_write.c:717
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #1 (kn->active#13){++++}-{0:0}:
kernfs_drain+0x284/0x600 fs/kernfs/dir.c:511
__kernfs_remove+0x3cf/0x660 fs/kernfs/dir.c:1513
kernfs_remove_by_name_ns+0xaf/0x130 fs/kernfs/dir.c:1722
kernfs_remove_by_name include/linux/kernfs.h:633 [inline]
remove_files fs/sysfs/group.c:28 [inline]
sysfs_remove_group+0xfc/0x2e0 fs/sysfs/group.c:328
sysfs_remove_groups+0x54/0xb0 fs/sysfs/group.c:352
device_remove_groups drivers/base/core.c:2843 [inline]
device_remove_attrs+0x229/0x280 drivers/base/core.c:2979
device_del+0x51f/0x8f0 drivers/base/core.c:3877
unregister_netdevice_many_notify+0x1e0e/0x2370 net/core/dev.c:12438
unregister_netdevice_many net/core/dev.c:12466 [inline]
unregister_netdevice_queue+0x31f/0x360 net/core/dev.c:12280
unregister_netdevice include/linux/netdevice.h:3408 [inline]
_cfg80211_unregister_wdev+0x155/0x570 net/wireless/core.c:1297
ieee80211_remove_interfaces+0x49c/0x6d0 net/mac80211/iface.c:2440
ieee80211_unregister_hw+0x5d/0x2c0 net/mac80211/main.c:1691
mac80211_hwsim_del_radio+0x28a/0x490 drivers/net/wireless/virtual/mac80211_hwsim.c:5916
remove_user_radios drivers/net/wireless/virtual/mac80211_hwsim.c:6727 [inline]
mac80211_hwsim_netlink_notify+0xfae/0x1310 drivers/net/wireless/virtual/mac80211_hwsim.c:6741
notifier_call_chain+0x1be/0x400 kernel/notifier.c:85
blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380
netlink_release+0x123b/0x1ad0 net/netlink/af_netlink.c:761
__sock_release net/socket.c:662 [inline]
sock_close+0xc3/0x240 net/socket.c:1455
__fput+0x44f/0xa70 fs/file_table.c:469
task_work_run+0x1d9/0x270 kernel/task_work.c:233
get_signal+0x11eb/0x1330 kernel/signal.c:2807
arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&rdev->wiphy.mtx){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:614 [inline]
__mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776
class_wiphy_constructor include/net/cfg80211.h:6441 [inline]
ieee80211_change_mac+0xb5/0x1410 net/mac80211/iface.c:324
netif_set_mac_address+0x317/0x4e0 net/core/dev.c:9989
do_setlink+0x9b1/0x4590 net/core/rtnetlink.c:3110
rtnl_changelink net/core/rtnetlink.c:3776 [inline]
__rtnl_newlink net/core/rtnetlink.c:3935 [inline]
rtnl_newlink+0x15a9/0x1be0 net/core/rtnetlink.c:4072
rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958
netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa68/0xad0 net/socket.c:2592
___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
__sys_sendmsg net/socket.c:2678 [inline]
__do_sys_sendmsg net/socket.c:2683 [inline]
__se_sys_sendmsg net/socket.c:2681 [inline]
__x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 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:
&rdev->wiphy.mtx --> kn->active#13 --> dev_addr_sem
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(dev_addr_sem);
lock(kn->active#13);
lock(dev_addr_sem);
lock(&rdev->wiphy.mtx);
*** DEADLOCK ***
2 locks held by syz.0.4107/21056:
#0: ffffffff8fbcb808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff8fbcb808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff8fbcb808 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071
#1: ffffffff8fbc12b0 (dev_addr_sem){++++}-{4:4}, at: do_setlink+0x806/0x4590 net/core/rtnetlink.c:3105
stack backtrace:
CPU: 0 UID: 0 PID: 21056 Comm: syz.0.4107 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
check_noncircular+0x12e/0x150 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 kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
__mutex_lock_common kernel/locking/mutex.c:614 [inline]
__mutex_lock+0x19f/0x1300 kernel/locking/mutex.c:776
class_wiphy_constructor include/net/cfg80211.h:6441 [inline]
ieee80211_change_mac+0xb5/0x1410 net/mac80211/iface.c:324
netif_set_mac_address+0x317/0x4e0 net/core/dev.c:9989
do_setlink+0x9b1/0x4590 net/core/rtnetlink.c:3110
rtnl_changelink net/core/rtnetlink.c:3776 [inline]
__rtnl_newlink net/core/rtnetlink.c:3935 [inline]
rtnl_newlink+0x15a9/0x1be0 net/core/rtnetlink.c:4072
rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958
netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa68/0xad0 net/socket.c:2592
___sys_sendmsg+0x2a5/0x360 net/socket.c:2646
__sys_sendmsg net/socket.c:2678 [inline]
__do_sys_sendmsg net/socket.c:2683 [inline]
__se_sys_sendmsg net/socket.c:2681 [inline]
__x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f909439c629
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f90951b3028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f9094616090 RCX: 00007f909439c629
RDX: 0000000000000000 RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007f9094432b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9094616128 R14: 00007f9094616090 R15: 00007fff601b4778
</TASK>
netlink: 8 bytes leftover after parsing attributes in process `syz.0.4107'.
netlink: 'syz.0.4107': attribute type 5 has an invalid length.
netlink: 20 bytes leftover after parsing attributes in process `syz.0.4107'.
geneve2: entered promiscuous mode
geneve2: entered allmulticast mode
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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reply other threads:[~2026-02-27 6:40 UTC|newest]
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