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: 191d, last: 7d13h

Sample crash report:

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

write to 0xffff88810d932730 of 8 bytes by task 10593 on cpu 1:
 i_size_write include/linux/fs.h:870 [inline]
 ext4_update_inode_size fs/ext4/ext4.h:3285 [inline]
 ext4_handle_inode_extension+0x226/0x550 fs/ext4/file.c:332
 ext4_dio_write_iter fs/ext4/file.c:558 [inline]
 ext4_file_write_iter+0xe48/0x1090 fs/ext4/file.c:662
 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 0xffff88810d932730 of 8 bytes by task 10595 on cpu 0:
 i_size_read include/linux/fs.h:848 [inline]
 do_page_cache_ra mm/readahead.c:254 [inline]
 ondemand_readahead+0x500/0x780 mm/readahead.c:549
 page_cache_sync_ra+0x1ab/0x1c0 mm/readahead.c:577
 page_cache_sync_readahead include/linux/pagemap.h:839 [inline]
 generic_file_buffered_read_get_pages+0x234/0xaf0 mm/filemap.c:2361
 generic_file_buffered_read+0x27f/0x9a0 mm/filemap.c:2481
 generic_file_read_iter+0x80/0x3d0 mm/filemap.c:2633
 ext4_file_read_iter+0x2d0/0x420 fs/ext4/file.c:74
 call_read_iter include/linux/fs.h:1895 [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+0x5db/0xca0 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1312 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xa9/0x130 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: 0 PID: 10595 Comm: syz-executor.3 Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (29):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Maintainers
ci2-upstream-kcsan-gce	2021/01/17 17:34	upstream	0da0a8a0	fd103621	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2021/01/05 00:56	upstream	36bbbd0e	2a28ff1f	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/31 00:32	upstream	f6e1ea19	ecb8c012	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/27 03:15	upstream	f838f8d2	821e0b09	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/26 01:12	upstream	5814bc2d	821e0b09	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/25 04:44	upstream	3913d00a	c2c1d1dd	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/23 01:25	upstream	614cb589	04201c06	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/20 03:39	upstream	467f8165	04201c06	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/10 10:43	upstream	a2f5ea9e	c090b4da	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/09 02:32	upstream	7d8761ba	40cc414d	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/07 00:25	upstream	8100a580	c521566d	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/11/25 01:09	upstream	80145ac2	e34b696c	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/11/18 09:53	upstream	111e91a6	09323409	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/11/15 20:04	upstream	0062442e	1bf9a662	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/11/04 08:39	upstream	4ef8451b	cba33199	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/10/26 23:20	upstream	41ba50b0	8b3eaf58	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/10/02 18:24	upstream	472e5b05	062c9832	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/09/30 01:25	upstream	fb0155a0	5abc3f1a	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/09/19 14:45	upstream	eb5f95f1	53ce8104	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/09/12 14:15	upstream	729e3d09	21d289c2	.config	log	report		adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/09/09 20:26	upstream	34d4ddd3	ac7ca78e	.config	log	report		adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/08/23 23:24	upstream	cb957121	cef5ae68	.config	log	report		adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/08/21 05:33	upstream	da2968ff	70160577	.config	log	report		adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/08/09 13:52	upstream	06a81c1c	70301872	.config	log	report		adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/08/05 12:40	upstream	c0842fbc	b7129355	.config	log	report		adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/08/05 00:25	upstream	c0842fbc	02034dac	.config	log	report		adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/08/02 22:25	upstream	142c3326	96dd3623	.config	log	report		adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/07/29 08:21	upstream	6ba1b005	19a8de55	.config	log	report		adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/07/17 12:54	upstream	07a56bb8	54b3c45e	.config	log	report		adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu