KCSAN: data-race in iput / writeback_sb

KCSAN: data-race in iput / writeback_sb_inodes (4)
Status: auto-closed as invalid on 2020/12/21 11:42
Reported-by: syzbot+738021518a55e3fd2572@syzkaller.appspotmail.com
First crash: 349d, last: 271d

similar bugs (5):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in iput / writeback_sb_inodes (2)	1	407d	407d	0/22	closed as invalid on 2020/06/18 14:13
upstream	KCSAN: data-race in iput / writeback_sb_inodes (3)	1	388d	388d	0/22	auto-closed as invalid on 2020/08/11 19:26
upstream	KCSAN: data-race in iput / writeback_sb_inodes (6)	2	45d	52d	0/22	auto-closed as invalid on 2021/07/20 06:50
upstream	KCSAN: data-race in iput / writeback_sb_inodes	1	508d	508d	0/22	auto-closed as invalid on 2020/05/18 05:32
upstream	KCSAN: data-race in iput / writeback_sb_inodes (5)	4	183d	207d	0/22	auto-closed as invalid on 2021/03/04 09:19

Sample crash report:

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

read-write to 0xffff88810d5d3bd8 of 8 bytes by task 26 on cpu 0:
 inode_sync_complete fs/fs-writeback.c:1210 [inline]
 writeback_sb_inodes+0xb29/0x1020 fs/fs-writeback.c:1749
 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:2272
 worker_thread+0x635/0xb90 kernel/workqueue.c:2418
 kthread+0x1fa/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff88810d5d3bd8 of 8 bytes by task 8457 on cpu 1:
 iput+0x2e/0x510 fs/inode.c:1670
 do_unlinkat+0x2c9/0x4d0 fs/namei.c:3903
 __do_sys_unlink fs/namei.c:3943 [inline]
 __se_sys_unlink fs/namei.c:3941 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:3941
 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: 8457 Comm: syz-executor.3 Not tainted 5.10.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (7):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info
ci2-upstream-kcsan-gce	2020/11/01 20:17	upstream	31f020064f9d	8bc4594f	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/30 14:24	upstream	02de58b24d2e	8516f6d3	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/18 02:04	upstream	4cbffc461ec9	8247808b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/05 21:30	upstream	9322c47b21b9	abf9ba4f	.config	log	report
ci2-upstream-kcsan-gce	2020/09/04 04:52	upstream	e28f0104343d	abf9ba4f	.config	log	report
ci2-upstream-kcsan-gce	2020/08/18 05:26	upstream	06a4ec1d9dc6	5ce13532	.config	log	report
ci2-upstream-kcsan-gce	2020/08/15 16:33	upstream	410520d07f5c	5ce13532	.config	log	report