KCSAN: data-race in __add_to_page_cache_locked / ext4

KCSAN: data-race in __add_to_page_cache_locked / ext4_writepages (2)
Status: auto-closed as invalid on 2021/01/25 22:34
Reported-by: syzbot+2c1b4e6c6c4369be36fd@syzkaller.appspotmail.com
First crash: 406d, last: 226d

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __add_to_page_cache_locked / ext4_writepages				45	425d	652d	0/22	closed as invalid on 2020/06/18 14:24

Sample crash report:

==================================================================
BUG: KCSAN: data-race in __add_to_page_cache_locked / ext4_writepages

read-write to 0xffff888135503d18 of 8 bytes by task 12382 on cpu 0:
 __add_to_page_cache_locked+0x3a2/0x6b0 mm/filemap.c:888
 add_to_page_cache_lru+0xa0/0x1b0 mm/filemap.c:939
 pagecache_get_page+0x60f/0x980 mm/filemap.c:1848
 grab_cache_page_write_begin+0x3f/0x70 mm/filemap.c:3358
 ext4_da_write_begin+0x34d/0xaf0 fs/ext4/inode.c:2976
 generic_perform_write+0x196/0x3a0 mm/filemap.c:3408
 ext4_buffered_write_iter+0x2e5/0x3d0 fs/ext4/file.c:270
 ext4_file_write_iter+0x45e/0x1090 fs/ext4/file.c:503
 call_write_iter include/linux/fs.h:1901 [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+0x5db/0xca0 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 0xffff888135503d18 of 8 bytes by task 12384 on cpu 1:
 ext4_writepages+0x131/0x1e30 fs/ext4/inode.c:2660
 do_writepages+0x7b/0x150 mm/page-writeback.c:2352
 __filemap_fdatawrite_range+0x19d/0x1d0 mm/filemap.c:422
 file_write_and_wait_range+0x9f/0x120 mm/filemap.c:761
 ext4_sync_file+0x105/0x6c0 fs/ext4/fsync.c:151
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2737 [inline]
 ext4_buffered_write_iter+0x384/0x3d0 fs/ext4/file.c:278
 ext4_file_write_iter+0x45e/0x1090 fs/ext4/file.c:503
 call_write_iter include/linux/fs.h:1901 [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+0x5db/0xca0 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: 12384 Comm: syz-executor.1 Not tainted 5.10.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (45):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info
ci2-upstream-kcsan-gce	2020/12/21 22:33	upstream	8653b778e454	04201c06	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/19 23:49	upstream	467f8165a2b0	04201c06	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/13 20:49	upstream	ec6f5e0e5ca0	8f160dd5	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/29 13:48	upstream	aae5ab854e38	a0092f9d	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/26 19:14	upstream	4df910620beb	2f1cec62	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/21 23:50	upstream	a349e4c65960	0d27f508	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/12 23:00	upstream	af5043c89a8e	16fca0c8	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/02 09:12	upstream	3cea11cd5e3b	8bc4594f	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/01 02:02	upstream	c2dc4c073fb7	8bc4594f	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/28 17:57	upstream	ed8780e3f2ec	f24824d3	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/28 00:15	upstream	ed8780e3f2ec	96e03c1c	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/23 22:07	upstream	0adc313c4f20	2bb6666c	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/19 07:31	upstream	7cf726a59435	fea47c01	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/12 09:00	upstream	bbf5c979011a	4a77ae0b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/19 01:46	upstream	92ab97adeefc	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/17 08:07	upstream	5925fa68fe82	8247808b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 13:32	upstream	fc4f28bb3daf	77507d02	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 06:37	upstream	fc4f28bb3daf	18d7d030	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/15 15:59	upstream	fc4f28bb3daf	9e681632	.config	log	report	info
ci2-upstream-kcsan-gce	2020/08/19 12:39	upstream	18445bf405cb	db787902	.config	log	report
ci2-upstream-kcsan-gce	2020/08/15 01:28	upstream	c9c9735c46f5	5ce13532	.config	log	report
ci2-upstream-kcsan-gce	2020/08/14 00:41	upstream	990f227371a4	54ce1ed6	.config	log	report
ci2-upstream-kcsan-gce	2020/08/10 15:02	upstream	fc80c51fd4b2	7adc7b65	.config	log	report
ci2-upstream-kcsan-gce	2020/08/09 02:13	upstream	06a81c1c7db9	f721e4a0	.config	log	report
ci2-upstream-kcsan-gce	2020/07/31 12:21	upstream	d8b9faec54ae	8df85ed9	.config	log	report
ci2-upstream-kcsan-gce	2020/07/26 01:33	upstream	04300d66f0a0	1f7cc1ca	.config	log	report
ci2-upstream-kcsan-gce	2020/07/23 22:58	upstream	f37e99aca03f	70c104a1	.config	log	report
ci2-upstream-kcsan-gce	2020/07/21 03:20	upstream	4fa640dc5230	d88894e6	.config	log	report
ci2-upstream-kcsan-gce	2020/07/20 09:39	upstream	5714ee50bb43	8caeeeb7	.config	log	report
ci2-upstream-kcsan-gce	2020/07/18 19:46	upstream	6cf7ccba29dc	9c812472	.config	log	report
ci2-upstream-kcsan-gce	2020/07/12 02:07	upstream	0aea6d5c5be3	7ba05d2d	.config	log	report
ci2-upstream-kcsan-gce	2020/07/11 10:42	upstream	1df0d8960499	7ba05d2d	.config	log	report
ci2-upstream-kcsan-gce	2020/07/10 11:25	upstream	42f82040ee66	56d01184	.config	log	report
ci2-upstream-kcsan-gce	2020/07/10 11:06	upstream	42f82040ee66	56d01184	.config	log	report
ci2-upstream-kcsan-gce	2020/07/08 19:51	upstream	63e1968a2c87	9f9845eb	.config	log	report
ci2-upstream-kcsan-gce	2020/07/05 13:23	upstream	35e884f89df4	22f87567	.config	log	report
ci2-upstream-kcsan-gce	2020/07/04 14:22	upstream	35e884f89df4	4f739670	.config	log	report
ci2-upstream-kcsan-gce	2020/06/30 08:20	upstream	7c30b859a947	917afeaa	.config	log	report
ci2-upstream-kcsan-gce	2020/06/28 14:12	upstream	719fdd32921f	a2cdad9d	.config	log	report
ci2-upstream-kcsan-gce	2020/06/28 12:14	upstream	719fdd32921f	a2cdad9d	.config	log	report
ci2-upstream-kcsan-gce	2020/06/27 23:02	upstream	6116dea80dfd	a2cdad9d	.config	log	report
ci2-upstream-kcsan-gce	2020/06/27 18:49	upstream	6116dea80dfd	a2cdad9d	.config	log	report
ci2-upstream-kcsan-gce	2020/06/27 14:57	upstream	1590a2e1c681	2defc703	.config	log	report
ci2-upstream-kcsan-gce	2020/06/26 07:30	upstream	4a21185cda0f	aea82c00	.config	log	report
ci2-upstream-kcsan-gce	2020/06/25 02:16	upstream	26e122e97a3d	9d60b18e	.config	log	report