[syzbot] [wireless?] divide error in mac80211_hwsim_link_info_changed (3)

[syzbot <syzbot+ca7a2759caaa6cd4e3db@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    254f49634ee1 Linux 7.1-rc1
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13b32348580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4caf64b1ee83dac0
dashboard link: https://syzkaller.appspot.com/bug?extid=ca7a2759caaa6cd4e3db
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/fd59c3aee25f/disk-254f4963.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2a93e1c819bd/vmlinux-254f4963.xz
kernel image: https://storage.googleapis.com/syzbot-assets/18c05b34ca3c/bzImage-254f4963.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ca7a2759caaa6cd4e3db@syzkaller.appspotmail.com

Oops: divide error: 0000 [#1] SMP KASAN PTI
CPU: 1 UID: 0 PID: 193 Comm: kworker/u8:6 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:mac80211_hwsim_link_info_changed+0x476/0xfc0 drivers/net/wireless/virtual/mac80211_hwsim.c:2734
Code: 3c 06 00 49 89 c6 48 8b 7c 24 20 74 0a e8 42 72 26 fb 48 8b 7c 24 20 48 8b 0f 89 ce 4c 89 e0 48 c1 e8 20 74 60 4c 89 e0 31 d2 <48> f7 f6 eb 5d e8 30 37 bb fa 4c 8b 74 24 20 49 8d 7e 10 e8 a2 e4
RSP: 0000:ffffc90002ea7860 EFLAGS: 00010246
RAX: 000650757bb12572 RBX: 0000000000000200 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88806fbe7b98
RBP: ffffc90002ea7958 R08: ffffffff903096f7 R09: 1ffffffff20612de
R10: dffffc0000000000 R11: fffffbfff20612df R12: 000650757bb12572
R13: ffff88806fbe7b18 R14: dffffc0000000000 R15: 1ffff920005d4f18
FS:  0000000000000000(0000) GS:ffff888125393000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f540c000 CR3: 0000000064b3a000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 drv_link_info_changed+0x505/0x880 net/mac80211/driver-ops.c:-1
 ieee80211_offchannel_return+0x375/0x500 net/mac80211/offchannel.c:160
 __ieee80211_scan_completed+0x75a/0xb40 net/mac80211/scan.c:519
 cfg80211_wiphy_work+0x2cf/0x460 net/wireless/core.c:513
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 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>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:mac80211_hwsim_link_info_changed+0x476/0xfc0 drivers/net/wireless/virtual/mac80211_hwsim.c:2734
Code: 3c 06 00 49 89 c6 48 8b 7c 24 20 74 0a e8 42 72 26 fb 48 8b 7c 24 20 48 8b 0f 89 ce 4c 89 e0 48 c1 e8 20 74 60 4c 89 e0 31 d2 <48> f7 f6 eb 5d e8 30 37 bb fa 4c 8b 74 24 20 49 8d 7e 10 e8 a2 e4
RSP: 0000:ffffc90002ea7860 EFLAGS: 00010246
RAX: 000650757bb12572 RBX: 0000000000000200 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88806fbe7b98
RBP: ffffc90002ea7958 R08: ffffffff903096f7 R09: 1ffffffff20612de
R10: dffffc0000000000 R11: fffffbfff20612df R12: 000650757bb12572
R13: ffff88806fbe7b18 R14: dffffc0000000000 R15: 1ffff920005d4f18
FS:  0000000000000000(0000) GS:ffff888125393000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f7487a54 CR3: 00000000608c4000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 3 bytes skipped:
   0:	49 89 c6             	mov    %rax,%r14
   3:	48 8b 7c 24 20       	mov    0x20(%rsp),%rdi
   8:	74 0a                	je     0x14
   a:	e8 42 72 26 fb       	call   0xfb267251
   f:	48 8b 7c 24 20       	mov    0x20(%rsp),%rdi
  14:	48 8b 0f             	mov    (%rdi),%rcx
  17:	89 ce                	mov    %ecx,%esi
  19:	4c 89 e0             	mov    %r12,%rax
  1c:	48 c1 e8 20          	shr    $0x20,%rax
  20:	74 60                	je     0x82
  22:	4c 89 e0             	mov    %r12,%rax
  25:	31 d2                	xor    %edx,%edx
* 27:	48 f7 f6             	div    %rsi <-- trapping instruction
  2a:	eb 5d                	jmp    0x89
  2c:	e8 30 37 bb fa       	call   0xfabb3761
  31:	4c 8b 74 24 20       	mov    0x20(%rsp),%r14
  36:	49 8d 7e 10          	lea    0x10(%r14),%rdi
  3a:	e8                   	.byte 0xe8
  3b:	a2                   	.byte 0xa2
  3c:	e4                   	.byte 0xe4


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