Subject: WARNING in __rate_control_send_low

From: syzbot <[email-masked]>
Date: Wed, 14 Oct 2020 05:01:24 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    bbf5c979 Linux 5.9
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12dc474f900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3d8333c88fe898d7
dashboard link: https://syzkaller.appspot.com/bug?extid=fdc5123366fb9c3fdc6d
compiler:       gcc (GCC) 10.1.0-syz 20200507

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

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

------------[ cut here ]------------
no supported rates for sta (null) (0xffffffff, band 0) in rate_mask 0xfff with flags 0x20
WARNING: CPU: 1 PID: 169 at net/mac80211/rate.c:349 __rate_control_send_low+0x4eb/0x5e0 net/mac80211/rate.c:349
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 169 Comm: kworker/u4:5 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: phy9 ieee80211_scan_work
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x198/0x1fd lib/dump_stack.c:118
 panic+0x382/0x7fb kernel/panic.c:231
 __warn.cold+0x20/0x4b kernel/panic.c:600
 report_bug+0x1bd/0x210 lib/bug.c:198
 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:234
 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536
RIP: 0010:__rate_control_send_low+0x4eb/0x5e0 net/mac80211/rate.c:349
Code: 14 48 89 44 24 08 e8 d4 8d b0 f9 44 8b 44 24 24 45 89 e9 44 89 e1 48 8b 74 24 08 44 89 f2 48 c7 c7 40 24 5f 89 e8 b7 ca 80 f9 <0f> 0b e9 e0 fd ff ff e8 a9 8d b0 f9 41 83 cd 10 e9 02 fc ff ff e8
RSP: 0018:ffffc900013f7688 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff88801e243468 RCX: 0000000000000000
RDX: ffff8880a884e100 RSI: ffffffff815f5a55 RDI: fffff5200027eec3
RBP: ffff88805f373148 R08: 0000000000000001 R09: ffff8880ae5318e7
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000020 R14: 00000000ffffffff R15: 0000000000000090
 rate_control_send_low+0x261/0x610 net/mac80211/rate.c:374
 rate_control_get_rate+0x1b9/0x5a0 net/mac80211/rate.c:887
 ieee80211_tx_h_rate_ctrl+0xa0f/0x1660 net/mac80211/tx.c:749
 invoke_tx_handlers_early+0xaf3/0x25e0 net/mac80211/tx.c:1784
 ieee80211_tx+0x250/0x430 net/mac80211/tx.c:1926
 ieee80211_xmit+0x2dd/0x3b0 net/mac80211/tx.c:2015
 __ieee80211_tx_skb_tid_band+0x20a/0x290 net/mac80211/tx.c:5351
 ieee80211_tx_skb_tid_band net/mac80211/ieee80211_i.h:1986 [inline]
 ieee80211_send_scan_probe_req net/mac80211/scan.c:610 [inline]
 ieee80211_scan_state_send_probe+0x39f/0x910 net/mac80211/scan.c:638
 ieee80211_scan_work+0x6df/0x19e0 net/mac80211/scan.c:1071
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Kernel Offset: disabled
Rebooting in 86400 seconds..

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