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: 21d, last: 1d02h
✨ 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 915d 915d 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 259d 388d 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 612d 608d 0/29 auto-obsoleted due to no activity on 2025/04/04 09:01

Sample crash report:
------------[ cut here ]------------
wlan0: Failed check-sdata-in-driver check, flags: 0x0
WARNING: net/mac80211/driver-ops.c:366 at drv_unassign_vif_chanctx+0x1ef/0x820 net/mac80211/driver-ops.c:366, CPU#1: kworker/u8:10/5850
Modules linked in:
CPU: 1 UID: 0 PID: 5850 Comm: kworker/u8:10 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
Workqueue: netns cleanup_net
RIP: 0010:drv_unassign_vif_chanctx+0x1f7/0x820 net/mac80211/driver-ops.c:366
Code: 00 00 e8 cc 40 d1 f6 48 8b 34 24 48 81 c6 20 01 00 00 48 89 34 24 e8 b8 40 d1 f6 48 8d 3d f1 71 1b 06 8b 54 24 0c 48 8b 34 24 <67> 48 0f b9 3a eb 07 4c 8d b3 68 0a 00 00 e8 96 40 d1 f6 4c 89 f2
RSP: 0018:ffffc900047b73d0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff8880541acec0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880541ac120 RDI: ffffffff91560870
RBP: ffff8880541f0f40 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 6b636f6c5f6b726f R12: ffff8880541aef88
R13: ffff888056304c00 R14: ffff8880541ad928 R15: ffff8880541aec70
FS:  0000000000000000(0000) GS:ffff888123c69000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6451b8d050 CR3: 000000005e5dd000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 ieee80211_assign_link_chanctx+0x5ec/0xeb0 net/mac80211/chan.c:1201
 __ieee80211_link_release_channel+0x2f8/0x5b0 net/mac80211/chan.c:2178
 ieee80211_link_release_channel+0x128/0x200 net/mac80211/chan.c:2494
 ieee80211_teardown_sdata+0xc4/0x250 net/mac80211/iface.c:916
 unregister_netdevice_many_notify+0x1407/0x2150 net/core/dev.c:12537
 unregister_netdevice_many net/core/dev.c:12589 [inline]
 unregister_netdevice_queue net/core/dev.c:12390 [inline]
 unregister_netdevice_queue+0x30b/0x3c0 net/core/dev.c:12376
 unregister_netdevice include/linux/netdevice.h:3487 [inline]
 _cfg80211_unregister_wdev+0x66e/0x830 net/wireless/core.c:1425
 ieee80211_remove_interfaces+0x34e/0x6e0 net/mac80211/iface.c:2492
 ieee80211_unregister_hw+0x55/0x360 net/mac80211/main.c:1717
 mac80211_hwsim_del_radio drivers/net/wireless/virtual/mac80211_hwsim_main.c:6251 [inline]
 hwsim_exit_net+0x891/0x1500 drivers/net/wireless/virtual/mac80211_hwsim_main.c:7260
 ops_exit_list net/core/net_namespace.c:200 [inline]
 ops_undo_list+0x2ee/0xab0 net/core/net_namespace.c:253
 cleanup_net+0x499/0x920 net/core/net_namespace.c:706
 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3387
 process_scheduled_works kernel/workqueue.c:3470 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3551
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 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:	00 00                	add    %al,(%rax)
   2:	e8 cc 40 d1 f6       	call   0xf6d140d3
   7:	48 8b 34 24          	mov    (%rsp),%rsi
   b:	48 81 c6 20 01 00 00 	add    $0x120,%rsi
  12:	48 89 34 24          	mov    %rsi,(%rsp)
  16:	e8 b8 40 d1 f6       	call   0xf6d140d3
  1b:	48 8d 3d f1 71 1b 06 	lea    0x61b71f1(%rip),%rdi        # 0x61b7213
  22:	8b 54 24 0c          	mov    0xc(%rsp),%edx
  26:	48 8b 34 24          	mov    (%rsp),%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 07                	jmp    0x38
  31:	4c 8d b3 68 0a 00 00 	lea    0xa68(%rbx),%r14
  38:	e8 96 40 d1 f6       	call   0xf6d140d3
  3d:	4c 89 f2             	mov    %r14,%rdx

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/28 11:57 upstream 1b78070aaef6 e2fa417d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in drv_unassign_vif_chanctx
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
2026/08/19 10:03 upstream b126f6f5940f 1e72964b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in drv_unassign_vif_chanctx
* Struck through repros no longer work on HEAD.