Subject: Re: WARNING in ieee80211_ibss_csa_beacon

From: syzbot <[email-masked]>
Date: Fri, 04 Dec 2020 18:28:08 -0800

syzbot has found a reproducer for the following issue on:

HEAD commit:    e87297fa Merge tag 'drm-fixes-2020-12-04' of git://anongit..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1412f617500000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e49433cfed49b7d9
dashboard link: https://syzkaller.appspot.com/bug?extid=b6c9fe29aefe68e4ad34
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15131837500000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14550ecf500000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
------------[ cut here ]------------
WARNING: CPU: 0 PID: 21 at net/mac80211/ibss.c:504 ieee80211_ibss_csa_beacon+0x5ec/0x730 net/mac80211/ibss.c:504
Modules linked in:
CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.10.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: phy10 ieee80211_csa_finalize_work
RIP: 0010:ieee80211_ibss_csa_beacon+0x5ec/0x730 net/mac80211/ibss.c:504
Code: ff e8 a8 b7 9c 00 31 ff 89 c5 89 c6 e8 9d 2c 27 f9 85 ed 0f 85 84 fa ff ff e8 40 34 27 f9 0f 0b e9 78 fa ff ff e8 34 34 27 f9 <0f> 0b 41 bd ea ff ff ff e9 e1 fd ff ff e8 72 b2 68 f9 e9 8f fa ff
RSP: 0018:ffffc90000dbfc50 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff88801c070c00 RCX: ffffffff8155a937
RDX: ffff888010e1b480 RSI: ffffffff8848d04c RDI: 0000000000000000
RBP: 0000000000000002 R08: 0000000000000001 R09: ffffffff8ebaf727
R10: fffffbfff1d75ee4 R11: 0000000000000001 R12: 0000000000000000
R13: ffff88801c0718f0 R14: ffff888022400c80 R15: ffff88801c071248
FS:  0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdcb7060000 CR3: 0000000012b2b000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ieee80211_set_after_csa_beacon net/mac80211/cfg.c:3133 [inline]
 __ieee80211_csa_finalize+0x504/0xbf0 net/mac80211/cfg.c:3189
 ieee80211_csa_finalize net/mac80211/cfg.c:3212 [inline]
 ieee80211_csa_finalize_work+0x131/0x170 net/mac80211/cfg.c:3237
 process_one_work+0x933/0x15a0 kernel/workqueue.c:2272
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296