WARNING in mac80211_hwsim_write_tsf

Status: upstream: reported on 2026/09/07 04:18
Subsystems: wireless
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+c5d94e4d897c2c21cb27@syzkaller.appspotmail.com
First crash: 4d03h, last: 4d03h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision
a15fe205 repro-c 🏃 WARNING in mac80211_hwsim_write_tsf 2026/09/07 06:43 2026/09/07 06:44 4f7b22a0
5f494329 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in mac80211_hwsim_write_tsf 2026/09/04 14:13 2026/09/04 14:13 2026/09/04 14:20 7ce8fcf4
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [wireless?] WARNING in mac80211_hwsim_write_tsf 0 (1) 2026/09/07 04:18

Sample crash report:
netlink: 80 bytes leftover after parsing attributes in process `syz.4.6946'.
------------[ cut here ]------------
c->control.rates[0].idx < 0
WARNING: ./include/net/mac80211.h:3413 at ieee80211_get_tx_rate include/net/mac80211.h:3413 [inline], CPU#1: syz.4.6946/31565
WARNING: ./include/net/mac80211.h:3413 at mac80211_hwsim_get_tx_rate drivers/net/wireless/virtual/mac80211_hwsim_main.c:1335 [inline], CPU#1: syz.4.6946/31565
WARNING: ./include/net/mac80211.h:3413 at mac80211_hwsim_write_tsf+0x4ca/0x6b0 drivers/net/wireless/virtual/mac80211_hwsim_main.c:1617, CPU#1: syz.4.6946/31565
Modules linked in:
CPU: 1 UID: 0 PID: 31565 Comm: syz.4.6946 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:ieee80211_get_tx_rate include/net/mac80211.h:3413 [inline]
RIP: 0010:mac80211_hwsim_get_tx_rate drivers/net/wireless/virtual/mac80211_hwsim_main.c:1335 [inline]
RIP: 0010:mac80211_hwsim_write_tsf+0x4ca/0x6b0 drivers/net/wireless/virtual/mac80211_hwsim_main.c:1617
Code: 41 5c 41 5d 41 5e 41 5f 5d e9 32 cd ab 04 e8 8d e8 8c fa 66 bd 64 00 4d 8d bc 24 a8 49 00 00 e9 18 fc ff ff e8 77 e8 8c fa 90 <0f> 0b 90 e9 86 fc ff ff 89 d9 80 e1 07 38 c1 0f 8c be fb ff ff be
RSP: 0018:ffffc90003eb6d78 EFLAGS: 00010283
RAX: ffffffff873ad2a9 RBX: ffff888058132a30 RCX: 0000000000080000
RDX: ffffc90005c19000 RSI: 000000000000023a RDI: 000000000000023b
RBP: ffff88805ae00f40 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff520007d6da0 R12: ffff88805ae03220
R13: ffff888058132a00 R14: dffffc0000000000 R15: ffffffffffffffff
FS:  00007f213d4426c0(0000) GS:ffff888124dda000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d723ffc CR3: 0000000039eac000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 mac80211_hwsim_tx_frame_no_nl+0x16b/0x1760 drivers/net/wireless/virtual/mac80211_hwsim_main.c:1913
 mac80211_hwsim_tx+0x18cb/0x2580 drivers/net/wireless/virtual/mac80211_hwsim_main.c:2276
 drv_tx net/mac80211/driver-ops.h:38 [inline]
 ieee80211_tx_frags+0x3df/0x890 net/mac80211/tx.c:1753
 __ieee80211_tx+0x267/0x580 net/mac80211/tx.c:1808
 ieee80211_tx+0x312/0x4b0 net/mac80211/tx.c:1991
 ieee80211_monitor_start_xmit+0xb33/0x1280 net/mac80211/tx.c:2486
 __netdev_start_xmit include/linux/netdevice.h:5429 [inline]
 netdev_start_xmit include/linux/netdevice.h:5438 [inline]
 xmit_one net/core/dev.c:3937 [inline]
 dev_hard_start_xmit+0x2cd/0x830 net/core/dev.c:3953
 __dev_queue_xmit+0x14c0/0x3820 net/core/dev.c:4926
 packet_snd net/packet/af_packet.c:3110 [inline]
 packet_sendmsg+0x3d0d/0x4f80 net/packet/af_packet.c:3142
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800
 __sock_sendmsg net/socket.c:815 [inline]
 __sys_sendto+0x408/0x5a0 net/socket.c:2281
 __do_sys_sendto net/socket.c:2288 [inline]
 __se_sys_sendto net/socket.c:2284 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2284
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f213c59e159
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:00007f213d442028 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f213c825fa0 RCX: 00007f213c59e159
RDX: 000000000000002b RSI: 0000200000000540 RDI: 000000000000000b
RBP: 00007f213c635024 R08: 0000200000000380 R09: 0000000000000014
R10: 0000000004000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f213c826038 R14: 00007f213c825fa0 R15: 00007f213c94fa48
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/03 04:10 upstream 940de590b839 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in mac80211_hwsim_write_tsf
* Struck through repros no longer work on HEAD.