KCSAN: data-race in __filemap_fdatawrite_range / xas_clear

KCSAN: data-race in __filemap_fdatawrite_range / xas_clear_mark
Status: closed as invalid on 2019/11/19 13:44
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 494d, last: 494d

similar bugs (3):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __filemap_fdatawrite_range / xas_clear_mark (3)	3	255d	290d	0/21	closed as invalid on 2020/06/18 14:13
upstream	KCSAN: data-race in __filemap_fdatawrite_range / xas_clear_mark (2)	4	367d	386d	0/21	auto-closed as invalid on 2020/05/07 21:06
upstream	KCSAN: data-race in __filemap_fdatawrite_range / xas_clear_mark (4)	26	5d19h	83d	0/21	moderation: reported on 2020/12/07 11:36

Sample crash report:

==================================================================
BUG: KCSAN: data-race in __filemap_fdatawrite_range / xas_clear_mark

write to 0xffff8880bac0b6d4 of 4 bytes by interrupt on cpu 1:
 xa_mark_clear lib/xarray.c:74 [inline]
 xas_clear_mark lib/xarray.c:917 [inline]
 xas_clear_mark+0x1a0/0x1d0 lib/xarray.c:898
 __xa_clear_mark+0xd3/0x100 lib/xarray.c:1713
 test_clear_page_writeback+0x449/0x790 mm/page-writeback.c:2731
 end_page_writeback+0x9e/0x190 mm/filemap.c:1338
 ext4_finish_bio+0x40d/0x520 fs/ext4/page-io.c:110
 ext4_end_bio+0xd2/0x310 fs/ext4/page-io.c:334
 bio_endio+0x3a8/0x4f0 block/bio.c:1818
 req_bio_endio block/blk-core.c:242 [inline]
 blk_update_request+0x427/0x7b0 block/blk-core.c:1462
 scsi_end_request+0x6b/0x3e0 drivers/scsi/scsi_lib.c:579
 scsi_io_completion+0x11d/0xc80 drivers/scsi/scsi_lib.c:963
 scsi_finish_command+0x280/0x380 drivers/scsi/scsi.c:228
 scsi_softirq_done+0x259/0x280 drivers/scsi/scsi_lib.c:1477
 blk_done_softirq+0x1eb/0x250 block/blk-softirq.c:37
 __do_softirq+0x115/0x33f kernel/softirq.c:292

read to 0xffff8880bac0b6d4 of 4 bytes by task 7375 on cpu 0:
 mapping_tagged include/linux/fs.h:521 [inline]
 __filemap_fdatawrite_range+0x125/0x230 mm/filemap.c:416
 filemap_write_and_wait_range mm/filemap.c:680 [inline]
 filemap_write_and_wait_range+0xb1/0x150 mm/filemap.c:674
 generic_file_read_iter+0x1015/0x1440 mm/filemap.c:2293
 ext4_file_read_iter fs/ext4/file.c:77 [inline]
 ext4_file_read_iter+0xfa/0x240 fs/ext4/file.c:65
 call_read_iter include/linux/fs.h:1889 [inline]
 generic_file_splice_read+0x35c/0x500 fs/splice.c:307
 do_splice_to+0xf2/0x130 fs/splice.c:877
 splice_direct_to_actor+0x1a1/0x510 fs/splice.c:954
 do_splice_direct+0x161/0x1e0 fs/splice.c:1063
 do_sendfile+0x384/0x7f0 fs/read_write.c:1464
 __do_sys_sendfile64 fs/read_write.c:1525 [inline]
 __se_sys_sendfile64 fs/read_write.c:1511 [inline]
 __x64_sys_sendfile64+0x12a/0x140 fs/read_write.c:1511
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7375 Comm: syz-executor.1 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2019/10/23 15:07	https://github.com/google/ktsan.git kcsan	05f22368	b602d64b	.config	log	report