KCSAN: data-race in generic_file_buffered_read / simple_write

KCSAN: data-race in generic_file_buffered_read / simple_write_end
Status: auto-closed as invalid on 2020/11/28 15:21
Reported-by: syzbot+90b70e3998542fb36ca4@syzkaller.appspotmail.com
First crash: 206d, last: 128d

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in generic_file_buffered_read / simple_write_end (2)				8	14d	84d	0/21	moderation: reported on 2020/12/07 12:09

Sample crash report:

==================================================================
BUG: KCSAN: data-race in generic_file_buffered_read / simple_write_end

write to 0xffff88800f9a87f0 of 8 bytes by task 19046 on cpu 0:
 i_size_write include/linux/fs.h:871 [inline]
 simple_write_end+0x1dc/0x340 fs/libfs.c:589
 generic_perform_write+0x23e/0x3a0 mm/filemap.c:3322
 __generic_file_write_iter+0x15c/0x330 mm/filemap.c:3440
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3472
 call_write_iter include/linux/fs.h:1887 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4b0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x42a/0x780 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:933
 splice_direct_to_actor+0x345/0x650 fs/splice.c:888
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x574/0xb70 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88800f9a87f0 of 8 bytes by task 19036 on cpu 1:
 i_size_read include/linux/fs.h:849 [inline]
 generic_file_buffered_read+0x13df/0x2110 mm/filemap.c:2294
 generic_file_read_iter+0x80/0x3d0 mm/filemap.c:2535
 call_read_iter include/linux/fs.h:1881 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:788 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:867
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x574/0xb70 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1318 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19036 Comm: syz-executor.0 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (67):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info
ci2-upstream-kcsan-gce	2020/10/24 15:20	upstream	f11901ed	a1839e81	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/21 13:25	upstream	c4d6fe73	99c64d5c	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/21 02:44	upstream	c4d6fe73	ff4a3345	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/19 23:21	upstream	bbe85027	ff4a3345	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/18 04:00	upstream	9d9af100	fea47c01	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/17 15:07	upstream	071a0578	fea47c01	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/15 21:54	upstream	726eb70e	6e262c73	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/12 20:48	upstream	1e6d1d96	d32b0bbf	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/12 16:04	upstream	bbf5c979	d32b0bbf	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/09 09:35	upstream	583090b1	fa79ed2a	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/05 23:21	upstream	7575fdda	1880b4a9	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/03 17:50	upstream	d3d45f82	1a3f9408	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/03 05:20	upstream	d3d45f82	2653fa43	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/01 21:15	upstream	fcadab74	9602ddf4	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/30 22:16	upstream	60e72093	a9767fb2	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/30 19:46	upstream	02de58b2	a9767fb2	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/29 18:42	upstream	fb0155a0	5abc3f1a	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/28 12:42	upstream	a1b8638b	6bfdbe89	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/26 15:59	upstream	7c7ec322	2d5ea0cb	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/26 07:14	upstream	7c7ec322	4a006f63	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/25 18:31	upstream	171d4ff7	4a006f63	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/24 17:56	upstream	171d4ff7	54289b08	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/20 19:59	upstream	bdcf11de	9564d2e9	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/20 12:15	upstream	325d0eab	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/20 10:19	upstream	325d0eab	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/20 08:58	upstream	325d0eab	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/20 05:41	upstream	325d0eab	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/19 23:44	upstream	eb5f95f1	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/19 16:48	upstream	eb5f95f1	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/19 11:20	upstream	eb5f95f1	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/19 10:05	upstream	eb5f95f1	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/19 00:24	upstream	92ab97ad	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/18 21:48	upstream	92ab97ad	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/18 15:16	upstream	10b82d51	38962c8b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/18 03:39	upstream	4cbffc46	8247808b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/17 23:18	upstream	4cbffc46	8247808b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/17 12:49	upstream	5925fa68	8247808b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/17 06:55	upstream	5925fa68	8247808b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/17 04:56	upstream	5925fa68	8247808b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 22:15	upstream	5925fa68	77507d02	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 20:50	upstream	5925fa68	77507d02	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 19:25	upstream	fc4f28bb	77507d02	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 11:10	upstream	fc4f28bb	18d7d030	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 08:35	upstream	fc4f28bb	18d7d030	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 07:32	upstream	fc4f28bb	18d7d030	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 05:00	upstream	fc4f28bb	18d7d030	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 04:38	upstream	fc4f28bb	18d7d030	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 01:43	upstream	fc4f28bb	18d7d030	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/15 20:16	upstream	fc4f28bb	18d7d030	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/15 18:25	upstream	fc4f28bb	9e681632	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/14 09:27	upstream	84b13499	2d3cdd63	.config	log	report
ci2-upstream-kcsan-gce	2020/09/14 07:50	upstream	84b13499	2d3cdd63	.config	log	report
ci2-upstream-kcsan-gce	2020/09/14 04:28	upstream	84b13499	2d3cdd63	.config	log	report
ci2-upstream-kcsan-gce	2020/09/14 01:41	upstream	84b13499	2d3cdd63	.config	log	report
ci2-upstream-kcsan-gce	2020/09/11 00:19	upstream	581cb3a2	ac7ca78e	.config	log	report
ci2-upstream-kcsan-gce	2020/09/07 16:42	upstream	f4d51dff	abf9ba4f	.config	log	report
ci2-upstream-kcsan-gce	2020/09/07 01:14	upstream	a8205e31	abf9ba4f	.config	log	report
ci2-upstream-kcsan-gce	2020/09/04 07:13	upstream	59126901	abf9ba4f	.config	log	report
ci2-upstream-kcsan-gce	2020/08/31 10:39	upstream	f75aef39	d5a3ae1f	.config	log	report
ci2-upstream-kcsan-gce	2020/08/30 20:48	upstream	dcc5c6f0	d5a3ae1f	.config	log	report
ci2-upstream-kcsan-gce	2020/08/28 17:54	upstream	15bc20c6	d5a3ae1f	.config	log	report
ci2-upstream-kcsan-gce	2020/08/10 10:43	upstream	fc80c51f	7adc7b65	.config	log	report
ci2-upstream-kcsan-gce	2020/08/09 22:14	upstream	9420f1ce	70301872	.config	log	report
ci2-upstream-kcsan-gce	2020/08/08 23:26	upstream	06a81c1c	f721e4a0	.config	log	report
ci2-upstream-kcsan-gce	2020/08/08 00:17	upstream	30185b69	ff51e522	.config	log	report