KCSAN: data-race in ext4_handle_inode_extension / ondemand

KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
Status: moderation: reported on 2020/12/07 11:36
Reported-by: syzbot+da42aa350977801533fc@syzkaller.appspotmail.com
First crash: 277d, last: 6d07h

Sample crash report:

==================================================================
BUG: KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead

write to 0xffff88810c7c4290 of 8 bytes by task 15289 on cpu 1:
 i_size_write include/linux/fs.h:872 [inline]
 ext4_update_inode_size fs/ext4/ext4.h:3292 [inline]
 ext4_handle_inode_extension+0x226/0x550 fs/ext4/file.c:331
 ext4_dio_write_iter fs/ext4/file.c:557 [inline]
 ext4_file_write_iter+0xef4/0x10b0 fs/ext4/file.c:661
 call_write_iter include/linux/fs.h:1977 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x7a6/0xe20 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88810c7c4290 of 8 bytes by task 15290 on cpu 0:
 i_size_read include/linux/fs.h:850 [inline]
 do_page_cache_ra mm/readahead.c:254 [inline]
 ondemand_readahead+0x500/0x780 mm/readahead.c:549
 page_cache_sync_ra+0x18f/0x1a0 mm/readahead.c:577
 page_cache_sync_readahead include/linux/pagemap.h:840 [inline]
 filemap_get_pages+0x1ba/0x660 mm/filemap.c:2375
 filemap_read+0x1ba/0x7b0 mm/filemap.c:2458
 generic_file_read_iter+0x82/0x410 mm/filemap.c:2609
 ext4_file_read_iter+0x2e0/0x420 fs/ext4/file.c:74
 call_read_iter include/linux/fs.h:1971 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:311
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2aa/0x650 fs/splice.c:870
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x7a6/0xe20 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1319 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1311
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15290 Comm: syz-executor.2 Not tainted 5.12.0-rc7-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	Title
ci2-upstream-kcsan-gce	2021/04/15 00:23	upstream	7f75285c	fcdb12ba	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/04/12 12:02	upstream	d434405a	6a81331a	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/04/11 07:03	upstream	52e44129	6a81331a	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/04/10 03:39	upstream	4e04e751	6a81331a	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/04/08 23:08	upstream	3fb4f979	6a81331a	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/04/03 07:15	upstream	0a84c2e4	6a81331a	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/03/29 11:25	upstream	a5e13c6d	a8529b82	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/03/28 21:19	upstream	36a14638	a8529b82	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/03/26 11:53	upstream	db24726b	a8529b82	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/03/23 16:30	upstream	84196390	e613994b	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/03/13 22:38	upstream	88fe4924	4a003785	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/03/13 07:20	upstream	f296bfd5	4a003785	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/03/06 04:37	upstream	280d542f	4a024a9b	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/01/31 01:02	upstream	8c947645	fc9fd31e	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/01/25 14:16	upstream	6ee1d745	52e37319	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/01/17 17:34	upstream	0da0a8a0	fd103621	.config	log	report	info	KCSAN: data-race in ext4_handle_inode_extension / ondemand_readahead
ci2-upstream-kcsan-gce	2021/01/05 00:56	upstream	36bbbd0e	2a28ff1f	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/31 00:32	upstream	f6e1ea19	ecb8c012	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/27 03:15	upstream	f838f8d2	821e0b09	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/26 01:12	upstream	5814bc2d	821e0b09	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/25 04:44	upstream	3913d00a	c2c1d1dd	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/23 01:25	upstream	614cb589	04201c06	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/20 03:39	upstream	467f8165	04201c06	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/10 10:43	upstream	a2f5ea9e	c090b4da	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/09 02:32	upstream	7d8761ba	40cc414d	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/07 00:25	upstream	8100a580	c521566d	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/25 01:09	upstream	80145ac2	e34b696c	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/18 09:53	upstream	111e91a6	09323409	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/15 20:04	upstream	0062442e	1bf9a662	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/04 08:39	upstream	4ef8451b	cba33199	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/26 23:20	upstream	41ba50b0	8b3eaf58	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/02 18:24	upstream	472e5b05	062c9832	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/30 01:25	upstream	fb0155a0	5abc3f1a	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/19 14:45	upstream	eb5f95f1	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/12 14:15	upstream	729e3d09	21d289c2	.config	log	report
ci2-upstream-kcsan-gce	2020/09/09 20:26	upstream	34d4ddd3	ac7ca78e	.config	log	report
ci2-upstream-kcsan-gce	2020/08/23 23:24	upstream	cb957121	cef5ae68	.config	log	report
ci2-upstream-kcsan-gce	2020/08/21 05:33	upstream	da2968ff	70160577	.config	log	report
ci2-upstream-kcsan-gce	2020/08/09 13:52	upstream	06a81c1c	70301872	.config	log	report
ci2-upstream-kcsan-gce	2020/08/05 12:40	upstream	c0842fbc	b7129355	.config	log	report
ci2-upstream-kcsan-gce	2020/08/05 00:25	upstream	c0842fbc	02034dac	.config	log	report
ci2-upstream-kcsan-gce	2020/08/02 22:25	upstream	142c3326	96dd3623	.config	log	report
ci2-upstream-kcsan-gce	2020/07/29 08:21	upstream	6ba1b005	19a8de55	.config	log	report
ci2-upstream-kcsan-gce	2020/07/17 12:54	upstream	07a56bb8	54b3c45e	.config	log	report