KCSAN: data-race in __xa_set_mark / writeback_sb

KCSAN: data-race in __xa_set_mark / writeback_sb_inodes (2)
Status: moderation: reported on 2020/12/07 11:37
Reported-by: syzbot+228fbd6131a379048fd0@syzkaller.appspotmail.com
First crash: 127d, last: 4d08h

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __xa_set_mark / writeback_sb_inodes				3	173d	207d	0/17	auto-closed as invalid on 2020/09/08 12:18

Sample crash report:

==================================================================
BUG: KCSAN: data-race in __xa_set_mark / writeback_sb_inodes

write to 0xffff88810f682924 of 4 bytes by task 10094 on cpu 0:
 xa_mark_set lib/xarray.c:69 [inline]
 xas_set_mark lib/xarray.c:889 [inline]
 __xa_set_mark+0x187/0x1b0 lib/xarray.c:1898
 __set_page_dirty+0x17e/0x1d0 fs/buffer.c:609
 mark_buffer_dirty+0x126/0x230 fs/buffer.c:1137
 __block_commit_write fs/buffer.c:2084 [inline]
 block_write_end+0x13d/0x230 fs/buffer.c:2162
 generic_write_end+0x5b/0x250 fs/buffer.c:2176
 ext4_da_write_end+0x59b/0x760 fs/ext4/inode.c:3111
 generic_perform_write+0x23e/0x3a0 mm/filemap.c:3419
 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
 ovl_write_iter+0x629/0x8f0 fs/overlayfs/file.c:358
 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: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

read to 0xffff88810f682924 of 4 bytes by task 24 on cpu 1:
 xa_marked include/linux/xarray.h:416 [inline]
 mapping_tagged include/linux/fs.h:488 [inline]
 requeue_inode fs/fs-writeback.c:1409 [inline]
 writeback_sb_inodes+0x91d/0x1020 fs/fs-writeback.c:1748
 wb_writeback+0x27d/0x660 fs/fs-writeback.c:1894
 wb_do_writeback+0x101/0x5d0 fs/fs-writeback.c:2039
 wb_workfn+0xb8/0x410 fs/fs-writeback.c:2080
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275
 worker_thread+0x635/0xb90 kernel/workqueue.c:2421
 kthread+0x1fd/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24 Comm: kworker/u4:1 Not tainted 5.11.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: writeback wb_workfn (flush-8:0)
==================================================================

Crashes (17):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Maintainers
ci2-upstream-kcsan-gce	2021/01/20 22:56	upstream	75439bc4	d4f4eca5	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/20 08:47	upstream	45dfb8a5	d4f4eca5	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/02 23:32	upstream	3516bd72	79264ae3	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/28 21:31	upstream	c76e02c5	8259d56c	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/21 23:10	upstream	8653b778	04201c06	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/04 22:26	upstream	e87297fa	20366b87	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/03 21:03	upstream	34816d20	59ad4022	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/02 04:22	upstream	509a1542	c42a35e9	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/12 21:04	upstream	af5043c8	77a55c8e	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/01 05:34	upstream	c2dc4c07	8bc4594f	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/10/31 00:20	upstream	f5d80856	18e33098	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/10/30 21:49	upstream	07e08873	a6e3ac3b	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/10/28 01:50	upstream	ed8780e3	96e03c1c	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/10/07 11:34	upstream	c85fb28b	1880b4a9	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/09/30 00:56	upstream	fb0155a0	5abc3f1a	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/09/29 13:15	upstream	fb0155a0	1b88c6d5	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/09/19 23:29	upstream	eb5f95f1	53ce8104	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk