[syzbot] [wireless?] WARNING in cfg80211_chandef_create

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b84a0ebe421c Add linux-next specific files for 20260313
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11308216580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e7280ad1f68b2dce
dashboard link: https://syzkaller.appspot.com/bug?extid=d9f5fabbbcf4b377d01f
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1090c8da580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=179338da580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/09145161a8a9/disk-b84a0ebe.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b64c254e474c/vmlinux-b84a0ebe.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a7c33f5f7f45/bzImage-b84a0ebe.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d9f5fa...@syzkaller.appspotmail.com

------------[ cut here ]------------
chan->band == NL80211_BAND_60GHZ || chan->band == NL80211_BAND_S1GHZ
WARNING: net/wireless/chan.c:35 at cfg80211_chandef_create+0x99/0x3d0 net/wireless/chan.c:34, CPU#1: syz.0.17/6021
Modules linked in:
CPU: 1 UID: 0 PID: 6021 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:cfg80211_chandef_create+0x99/0x3d0 net/wireless/chan.c:34
Code: 8b 26 4c 89 e7 48 c7 c6 20 78 26 90 e8 60 be ad f6 49 83 fc 04 74 0d 41 83 fc 02 75 12 e8 cf b8 ad f6 eb 05 e8 c8 b8 ad f6 90 <0f> 0b 90 eb 05 e8 bd b8 ad f6 89 ef 48 c7 c6 40 78 26 90 e8 2f be
RSP: 0018:ffffc90003986f30 EFLAGS: 00010293
RAX: ffffffff8b193a38 RBX: ffffc900039870a0 RCX: ffff888032143d00
RDX: 0000000000000000 RSI: ffffffff90267820 RDI: 0000000000000004
RBP: 0000000000000002 R08: ffff888032143d00 R09: 0000000000000002
R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000004
R13: dffffc0000000000 R14: ffff888012a762f8 R15: ffffc900039870a8
FS: 0000555592955500(0000) GS:ffff888124ee0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbf5f187600 CR3: 0000000077436000 CR4: 00000000003526f0
Call Trace:
<TASK>
_nl80211_parse_chandef+0x437/0x1300 net/wireless/nl80211.c:3637
__nl80211_set_channel+0x248/0x880 net/wireless/nl80211.c:3761
nl80211_set_wiphy+0x116b/0x2fa0 net/wireless/nl80211.c:-1
genl_family_rcv_msg_doit+0x22a/0x330 net/netlink/genetlink.c:1114
genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
genl_rcv_msg+0x61c/0x7a0 net/netlink/genetlink.c:1209
netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
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+0x112/0x150 net/socket.c:796
__sock_sendmsg net/socket.c:811 [inline]
____sys_sendmsg+0x589/0x8c0 net/socket.c:2668
___sys_sendmsg+0x2a5/0x360 net/socket.c:2722
__sys_sendmsg net/socket.c:2754 [inline]
__do_sys_sendmsg net/socket.c:2759 [inline]
__se_sys_sendmsg net/socket.c:2757 [inline]
__x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2757
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: 0033:0x7fbf5f19c799
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:00007ffe1eb2d0b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fbf5f415fa0 RCX: 00007fbf5f19c799
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000004
RBP: 00007fbf5f232c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbf5f415fac R14: 00007fbf5f415fa0 R15: 00007fbf5f415fa0
</TASK>


---
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[Lachlan Hodges]

> HEAD commit: b84a0ebe421c Add linux-next specific files for 20260313

I think this didn't have your fix already?

lachlan

[Johannes Berg]

On Wed, 2026-03-18 at 11:53 +1100, Lachlan Hodges wrote:
> > HEAD commit: b84a0ebe421c Add linux-next specific files for 20260313
>
> I think this didn't have your fix already?

Indeed, looks like that tree got cut between your and my commits, even
though they less than eight hours apart :)

johannes