syzbot
WARNING in drv_unassign_vif_chanctx (4)
Status:
upstream: reported on 2026/08/13 00:09
Subsystems:
wireless
Labels:
prio:low
[Documentation on labels]
Reported-by: syzbot+63a84ea9c0f57d6133fa@syzkaller.appspotmail.com
First crash: 10d, last: 2d19h
Sample crash report:
IPVS: stopping backup sync thread 17324 ...
------------[ cut here ]------------
wlan0: Failed check-sdata-in-driver check, flags: 0x0
WARNING: net/mac80211/driver-ops.c:366 at drv_unassign_vif_chanctx+0x498/0x7d0 net/mac80211/driver-ops.c:366, CPU#1: kworker/u8:18/9547
Modules linked in:
CPU: 1 UID: 0 PID: 9547 Comm: kworker/u8:18 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: netns cleanup_net
RIP: 0010:drv_unassign_vif_chanctx+0x4e5/0x7d0 net/mac80211/driver-ops.c:366
Code: 8d 78 0a 00 00 48 8b 02 48 8d b0 20 01 00 00 48 85 c0 48 0f 44 f1 42 0f b6 44 3d 00 84 c0 0f 85 95 01 00 00 41 8b 16 48 89 df <67> 48 0f b9 3a e9 04 fd ff ff e8 5c 73 8b f6 90 0f 0b 90 e9 3d fe
RSP: 0018:ffffc900039af090 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffff9069a660 RCX: ffff888082fd5938
RDX: 0000000000000000 RSI: ffff888082fd4120 RDI: ffffffff9069a660
RBP: 1ffff110105fab25 R08: ffffffff90578f37 R09: 1ffffffff20af1e6
R10: dffffc0000000000 R11: fffffbfff20af1e7 R12: ffff888082fd6c70
R13: ffff888082fd4ec0 R14: ffff888082fd5928 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888125049000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fffc1690ff8 CR3: 000000007c6bf000 CR4: 0000000000350ef0
Call Trace:
<TASK>
ieee80211_assign_link_chanctx+0x234/0xcd0 net/mac80211/chan.c:1199
__ieee80211_link_release_channel+0x3c6/0x610 net/mac80211/chan.c:2176
ieee80211_teardown_sdata+0xc1/0x240 net/mac80211/iface.c:916
unregister_netdevice_many_notify+0x1acd/0x2140 net/core/dev.c:12471
unregister_netdevice_many net/core/dev.c:12513 [inline]
unregister_netdevice_queue+0x2f5/0x340 net/core/dev.c:12324
unregister_netdevice include/linux/netdevice.h:3474 [inline]
_cfg80211_unregister_wdev+0x156/0x5a0 net/wireless/core.c:1422
ieee80211_remove_interfaces+0x49c/0x6a0 net/mac80211/iface.c:2492
ieee80211_unregister_hw+0x5d/0x2c0 net/mac80211/main.c:1718
mac80211_hwsim_del_radio+0x28a/0x4a0 drivers/net/wireless/virtual/mac80211_hwsim_main.c:6226
hwsim_exit_net+0xe8e/0xf50 drivers/net/wireless/virtual/mac80211_hwsim_main.c:7207
ops_exit_list net/core/net_namespace.c:199 [inline]
ops_undo_list+0x43d/0x8d0 net/core/net_namespace.c:252
cleanup_net+0x572/0x810 net/core/net_namespace.c:702
process_one_work kernel/workqueue.c:3322 [inline]
process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
----------------
Code disassembly (best guess):
0: 8d 78 0a lea 0xa(%rax),%edi
3: 00 00 add %al,(%rax)
5: 48 8b 02 mov (%rdx),%rax
8: 48 8d b0 20 01 00 00 lea 0x120(%rax),%rsi
f: 48 85 c0 test %rax,%rax
12: 48 0f 44 f1 cmove %rcx,%rsi
16: 42 0f b6 44 3d 00 movzbl 0x0(%rbp,%r15,1),%eax
1c: 84 c0 test %al,%al
1e: 0f 85 95 01 00 00 jne 0x1b9
24: 41 8b 16 mov (%r14),%edx
27: 48 89 df mov %rbx,%rdi
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: e9 04 fd ff ff jmp 0xfffffd38
34: e8 5c 73 8b f6 call 0xf68b7395
39: 90 nop
3a: 0f 0b ud2
3c: 90 nop
3d: e9 .byte 0xe9
3e: 3d .byte 0x3d
3f: fe .byte 0xfe
* Struck through repros no longer work on HEAD.