KCSAN: data-race in snd_seq_oss_readq_clear / snd_seq_oss_readq_put

KCSAN: data-race in snd_seq_oss_readq_clear / snd_seq_oss_readq_put_event
Status: auto-closed as invalid on 2020/09/25 17:37
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 345d, last: 345d

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in snd_seq_oss_readq_clear / snd_seq_oss_readq_put_event (2)				2	274d	294d	0/22	auto-closed as invalid on 2020/12/05 08:21

Sample crash report:

==================================================================
BUG: KCSAN: data-race in snd_seq_oss_readq_clear / snd_seq_oss_readq_put_event

write to 0xffff888073c19388 of 4 bytes by task 22776 on cpu 1:
 snd_seq_oss_readq_clear+0x35/0x90 sound/core/seq/oss/seq_oss_readq.c:77
 snd_seq_oss_reset+0x102/0x160 sound/core/seq/oss/seq_oss_init.c:445
 snd_seq_oss_release+0x76/0x170 sound/core/seq/oss/seq_oss_init.c:412
 odev_release+0x3a/0x60 sound/core/seq/oss/seq_oss.c:140
 __fput+0x246/0x4d0 fs/file_table.c:281
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:141
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:139 [inline]
 exit_to_user_mode_prepare+0x1b2/0x210 kernel/entry/common.c:166
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:241
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888073c19388 of 4 bytes by task 6 on cpu 0:
 snd_seq_oss_readq_put_event+0x38/0x150 sound/core/seq/oss/seq_oss_readq.c:146
 send_synth_event sound/core/seq/oss/seq_oss_midi.c:586 [inline]
 snd_seq_oss_midi_input+0x4ea/0x500 sound/core/seq/oss/seq_oss_midi.c:522
 snd_seq_oss_event_input+0xbc/0x100 sound/core/seq/oss/seq_oss_event.c:429
 snd_seq_deliver_single_event+0x31b/0x4f0 sound/core/seq/seq_clientmgr.c:638
 deliver_to_subscribers sound/core/seq/seq_clientmgr.c:693 [inline]
 snd_seq_deliver_event+0x392/0x4a0 sound/core/seq/seq_clientmgr.c:828
 snd_seq_kernel_client_dispatch+0x16f/0x190 sound/core/seq/seq_clientmgr.c:2323
 snd_vmidi_output_work+0x16d/0x200 sound/core/seq/seq_virmidi.c:150
 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6 Comm: kworker/0:0H Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_highpri snd_vmidi_output_work
==================================================================

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2020/08/21 17:34	upstream	da2968ff879b	1d75fe45	.config	log	report