syzbot


divide error in mac80211_hwsim_bss_info_changed (2)

Status: upstream: reported on 2025/06/19 11:01
Reported-by: syzbot+a518089a5190684ec87f@syzkaller.appspotmail.com
First crash: 9d03h, last: 8d20h
Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 divide error in mac80211_hwsim_bss_info_changed 3 260d 351d 0/3 auto-obsoleted due to no activity on 2025/01/18 21:46
android-54 divide error in mac80211_hwsim_bss_info_changed 2 1719d 1727d 0/2 auto-closed as invalid on 2021/02/09 23:56
upstream divide error in mac80211_hwsim_bss_info_changed (2) wireless 2 1300d 1348d 0/29 auto-closed as invalid on 2022/04/04 22:30
linux-4.19 divide error in mac80211_hwsim_bss_info_changed (2) 1 852d 852d 0/1 upstream: reported on 2023/02/27 09:41
upstream divide error in mac80211_hwsim_bss_info_changed wireless 1 1536d 1503d 0/29 auto-closed as invalid on 2021/08/12 01:33
linux-4.19 divide error in mac80211_hwsim_bss_info_changed 1 982d 982d 0/1 auto-obsoleted due to no activity on 2023/02/16 17:15

Sample crash report:
divide error: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 4618 Comm: kworker/u4:13 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: phy17 ieee80211_roc_work
RIP: 0010:mac80211_hwsim_bss_info_changed+0x3d6/0xea0 drivers/net/wireless/mac80211_hwsim.c:2037
Code: 00 4d 03 34 24 42 80 3c 2b 00 4c 8b 64 24 18 74 0e 48 89 fb 4c 89 e7 e8 c8 f8 16 fc 48 89 df 49 8b 0c 24 89 ce 4c 89 f0 31 d2 <48> f7 f6 29 d1 48 69 f1 e8 03 00 00 31 d2 b9 05 00 00 00 e8 b2 2b
RSP: 0018:ffffc90002f8fa80 EFLAGS: 00010246
RAX: 000637f0b716dcc8 RBX: 1ffff1100a673df8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88805339f060
RBP: ffffc90002f8fb48 R08: dffffc0000000000 R09: fffffbfff1ff3626
R10: fffffbfff1ff3626 R11: 1ffffffff1ff3625 R12: ffff88805339efc0
R13: dffffc0000000000 R14: 000637f0b716dcc8 R15: 0000000000000200
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff0419bda8 CR3: 000000007ab6d000 CR4: 00000000003506f0
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+0x314/0x450 net/mac80211/offchannel.c:158
 __ieee80211_roc_work+0x1f9/0x2b0 net/mac80211/offchannel.c:444
 ieee80211_roc_work+0x2b/0x40 net/mac80211/offchannel.c:458
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Modules linked in:
---[ end trace 2045d0d13568f7ef ]---
RIP: 0010:mac80211_hwsim_bss_info_changed+0x3d6/0xea0 drivers/net/wireless/mac80211_hwsim.c:2037
Code: 00 4d 03 34 24 42 80 3c 2b 00 4c 8b 64 24 18 74 0e 48 89 fb 4c 89 e7 e8 c8 f8 16 fc 48 89 df 49 8b 0c 24 89 ce 4c 89 f0 31 d2 <48> f7 f6 29 d1 48 69 f1 e8 03 00 00 31 d2 b9 05 00 00 00 e8 b2 2b
RSP: 0018:ffffc90002f8fa80 EFLAGS: 00010246
RAX: 000637f0b716dcc8 RBX: 1ffff1100a673df8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88805339f060
RBP: ffffc90002f8fb48 R08: dffffc0000000000 R09: fffffbfff1ff3626
R10: fffffbfff1ff3626 R11: 1ffffffff1ff3625 R12: ffff88805339efc0
R13: dffffc0000000000 R14: 000637f0b716dcc8 R15: 0000000000000200
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff0419bda8 CR3: 000000007ab6d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	00 4d 03             	add    %cl,0x3(%rbp)
   3:	34 24                	xor    $0x24,%al
   5:	42 80 3c 2b 00       	cmpb   $0x0,(%rbx,%r13,1)
   a:	4c 8b 64 24 18       	mov    0x18(%rsp),%r12
   f:	74 0e                	je     0x1f
  11:	48 89 fb             	mov    %rdi,%rbx
  14:	4c 89 e7             	mov    %r12,%rdi
  17:	e8 c8 f8 16 fc       	call   0xfc16f8e4
  1c:	48 89 df             	mov    %rbx,%rdi
  1f:	49 8b 0c 24          	mov    (%r12),%rcx
  23:	89 ce                	mov    %ecx,%esi
  25:	4c 89 f0             	mov    %r14,%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:	31 d2                	xor    %edx,%edx
  38:	b9 05 00 00 00       	mov    $0x5,%ecx
  3d:	e8                   	.byte 0xe8
  3e:	b2 2b                	mov    $0x2b,%dl

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/19 18:14 linux-5.15.y 1c700860e8bc ed3e87f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan divide error in mac80211_hwsim_bss_info_changed
2025/06/19 11:00 linux-5.15.y 1c700860e8bc ed3e87f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan divide error in mac80211_hwsim_bss_info_changed
* Struck through repros no longer work on HEAD.