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
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
679f3148 repro-c 💥 WARNING in drv_unassign_vif_chanctx (4) 2026/08/13 14:12 2026/08/13 14:12 2026/08/13 19:49 0165196a
4257e155 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in drv_unassign_vif_chanctx (4) 2026/08/10 00:28 2026/08/10 00:28 2026/08/10 01:42 5d63f80b
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [wireless?] WARNING in drv_unassign_vif_chanctx (4) 0 (1) 2026/08/13 00:09
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in drv_unassign_vif_chanctx wireless -1 2 904d 904d 0/29 auto-obsoleted due to no activity on 2024/06/05 06:49
upstream WARNING in drv_unassign_vif_chanctx (3) wireless -1 syz, C 2965 248d 378d 0/29 auto-obsoleted due to no activity on 2026/02/20 22:07
upstream WARNING in drv_unassign_vif_chanctx (2) wireless -1 1 601d 597d 0/29 auto-obsoleted due to no activity on 2025/04/04 09:01

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

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/15 22:25 upstream 15ef2f78c49d 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in drv_unassign_vif_chanctx
2026/08/08 09:30 upstream 9a143525f62b e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in drv_unassign_vif_chanctx
* Struck through repros no longer work on HEAD.