KCSAN: data-race in snd_rawmidi_kernel_write1 / snd_rawmidi

KCSAN: data-race in snd_rawmidi_kernel_write1 / snd_rawmidi_write (3)
Status: auto-closed as invalid on 2020/08/20 11:35
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 483d, last: 460d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in snd_rawmidi_kernel_write1 / snd_rawmidi_write				16	598d	707d	0/22	auto-closed as invalid on 2020/05/09 17:19
upstream	KCSAN: data-race in snd_rawmidi_kernel_write1 / snd_rawmidi_write (2)				5	500d	526d	0/22	closed as invalid on 2020/06/18 14:24

Sample crash report:

==================================================================
BUG: KCSAN: data-race in snd_rawmidi_kernel_write1 / snd_rawmidi_write

write to 0xffff888100b5e1b8 of 8 bytes by task 12350 on cpu 0:
 snd_rawmidi_kernel_write1+0x1e1/0x430 sound/core/rawmidi.c:1378
 snd_rawmidi_write+0x31b/0x6b0 sound/core/rawmidi.c:1452
 __kernel_write+0x12c/0x5a0 fs/read_write.c:528
 write_pipe_buf+0x96/0xc0 fs/splice.c:799
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x1f7/0x4f0 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 default_file_splice_write fs/splice.c:811 [inline]
 do_splice_from fs/splice.c:847 [inline]
 direct_splice_actor+0xee/0x160 fs/splice.c:1016
 splice_direct_to_actor+0x365/0x660 fs/splice.c:971
 do_splice_direct+0xf2/0x170 fs/splice.c:1059
 do_sendfile+0x562/0xb10 fs/read_write.c:1540
 __do_sys_sendfile64 fs/read_write.c:1601 [inline]
 __se_sys_sendfile64 fs/read_write.c:1587 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1587
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888100b5e1b8 of 8 bytes by task 12348 on cpu 1:
 snd_rawmidi_write+0x2dd/0x6b0 sound/core/rawmidi.c:1447
 __kernel_write+0x12c/0x5a0 fs/read_write.c:528
 write_pipe_buf+0x96/0xc0 fs/splice.c:799
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x1f7/0x4f0 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 default_file_splice_write fs/splice.c:811 [inline]
 do_splice_from fs/splice.c:847 [inline]
 direct_splice_actor+0xee/0x160 fs/splice.c:1016
 splice_direct_to_actor+0x365/0x660 fs/splice.c:971
 do_splice_direct+0xf2/0x170 fs/splice.c:1059
 do_sendfile+0x562/0xb10 fs/read_write.c:1540
 __do_sys_sendfile64 fs/read_write.c:1601 [inline]
 __se_sys_sendfile64 fs/read_write.c:1587 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1587
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12348 Comm: syz-executor.3 Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (5):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report
ci2-upstream-kcsan-gce	2020/07/16 11:30	upstream	f8456690ba8e	b090c643	.config	log	report
ci2-upstream-kcsan-gce	2020/07/01 05:56	upstream	7c30b859a947	c0383ebe	.config	log	report
ci2-upstream-kcsan-gce	2020/06/29 05:13	upstream	9ebcfadb0610	a2cdad9d	.config	log	report
ci2-upstream-kcsan-gce	2020/06/28 21:30	upstream	91a9a90d040e	a2cdad9d	.config	log	report
ci2-upstream-kcsan-gce	2020/06/24 09:07	upstream	3e08a95294a4	bbad15ae	.config	log	report