[v5.15] divide error in mac80211_hwsim_bss_info_changed (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c86c4726e7f0 Linux 5.15.211
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11f7db46580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6f8e2266b61925dc
dashboard link: https://syzkaller.appspot.com/bug?extid=3217247356ff032ef556
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c3e980557785/disk-c86c4726.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5fbaf3714ad0/vmlinux-c86c4726.xz
kernel image: https://storage.googleapis.com/syzbot-assets/de60a4f1e940/bzImage-c86c4726.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+321724...@syzkaller.appspotmail.com

divide error: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 4426 Comm: kworker/u4:13 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Workqueue: phy15 ieee80211_roc_work
RIP: 0010:mac80211_hwsim_bss_info_changed+0x3ed/0xea0 drivers/net/wireless/mac80211_hwsim.c:2037
Code: 40 3d 00 00 4c 03 2b 48 b8 00 00 00 00 00 fc ff df 41 80 3c 04 00 74 08 4c 89 f7 e8 ad f1 05 fc 49 8b 0e 89 ce 4c 89 e8 31 d2 <48> f7 f6 29 d1 48 69 f1 e8 03 00 00 48 8b 7c 24 18 31 d2 b9 05 00
RSP: 0018:ffffc900031afa80 EFLAGS: 00010246
RAX: 000656ccb1f83deb RBX: ffff8880704ff180 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000040
RBP: ffffc900031afb48 R08: ffffffff901e912f R09: 1ffffffff203d225
R10: dffffc0000000000 R11: fffffbfff203d226 R12: 1ffff1100e09fe04
R13: 000656ccb1f83deb R14: ffff8880704ff020 R15: 0000000000000200
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005582a7609f28 CR3: 0000000061d5f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
drv_bss_info_changed net/mac80211/driver-ops.h:177 [inline]
ieee80211_bss_info_change_notify+0x307/0x550 net/mac80211/main.c:212
ieee80211_offchannel_return+0x312/0x450 net/mac80211/offchannel.c:158
__ieee80211_roc_work+0x1f3/0x2b0 net/mac80211/offchannel.c:444
ieee80211_roc_work+0x2b/0x40 net/mac80211/offchannel.c:458
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>
Modules linked in:
---[ end trace f68b1455c6ac3a3f ]---
RIP: 0010:mac80211_hwsim_bss_info_changed+0x3ed/0xea0 drivers/net/wireless/mac80211_hwsim.c:2037
Code: 40 3d 00 00 4c 03 2b 48 b8 00 00 00 00 00 fc ff df 41 80 3c 04 00 74 08 4c 89 f7 e8 ad f1 05 fc 49 8b 0e 89 ce 4c 89 e8 31 d2 <48> f7 f6 29 d1 48 69 f1 e8 03 00 00 48 8b 7c 24 18 31 d2 b9 05 00
RSP: 0018:ffffc900031afa80 EFLAGS: 00010246
RAX: 000656ccb1f83deb RBX: ffff8880704ff180 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000040
RBP: ffffc900031afb48 R08: ffffffff901e912f R09: 1ffffffff203d225
R10: dffffc0000000000 R11: fffffbfff203d226 R12: 1ffff1100e09fe04
R13: 000656ccb1f83deb R14: ffff8880704ff020 R15: 0000000000000200
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005577cd4a6000 CR3: 000000002b589000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 40 3d 00 00 4c 03 rex cmp $0x34c0000,%eax
6: 2b 48 b8 sub -0x48(%rax),%ecx
9: 00 00 add %al,(%rax)
b: 00 00 add %al,(%rax)
d: 00 fc add %bh,%ah
f: ff lcall (bad)
10: df 41 80 filds -0x80(%rcx)
13: 3c 04 cmp $0x4,%al
15: 00 74 08 4c add %dh,0x4c(%rax,%rcx,1)
19: 89 f7 mov %esi,%edi
1b: e8 ad f1 05 fc call 0xfc05f1cd
20: 49 8b 0e mov (%r14),%rcx
23: 89 ce mov %ecx,%esi
25: 4c 89 e8 mov %r13,%rax
28: 31 d2 xor %edx,%edx
* 2a: 48 f7 f6 div %rsi <-- trapping instruction
2d: 29 d1 sub %edx,%ecx
2f: 48 69 f1 e8 03 00 00 imul $0x3e8,%rcx,%rsi
36: 48 8b 7c 24 18 mov 0x18(%rsp),%rdi
3b: 31 d2 xor %edx,%edx
3d: b9 .byte 0xb9
3e: 05 .byte 0x5


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