KCSAN: data-race in iput / writeback_single

KCSAN: data-race in iput / writeback_single_inode (2)
Status: auto-closed as invalid on 2020/11/13 23:11
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 347d, last: 347d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in iput / writeback_single_inode				1	407d	407d	0/22	auto-closed as invalid on 2020/09/15 05:18
upstream	KCSAN: data-race in iput / writeback_single_inode (3)				4	151d	159d	0/22	auto-closed as invalid on 2021/05/28 21:32

Sample crash report:

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

write to 0xffff88810a14d1c0 of 8 bytes by task 19988 on cpu 0:
 writeback_single_inode+0x102/0x580 fs/fs-writeback.c:1567
 sync_inode fs/fs-writeback.c:2605 [inline]
 sync_inode_metadata+0x52/0x70 fs/fs-writeback.c:2625
 ext4_fsync_nojournal fs/ext4/fsync.c:92 [inline]
 ext4_sync_file+0x335/0x6e0 fs/ext4/fsync.c:170
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2747 [inline]
 ext4_buffered_write_iter+0x369/0x3b0 fs/ext4/file.c:276
 ext4_file_write_iter+0x768/0x1060 include/linux/fs.h:784
 call_write_iter include/linux/fs.h:1882 [inline]
 do_iter_readv_writev+0x32e/0x3d0 fs/read_write.c:721
 do_iter_write+0x112/0x4b0 fs/read_write.c:1026
 vfs_iter_write+0x4c/0x70 fs/read_write.c:1067
 iter_file_splice_write+0x41a/0x770 fs/splice.c:770
 do_splice_from fs/splice.c:866 [inline]
 direct_splice_actor+0x95/0x160 fs/splice.c:1036
 splice_direct_to_actor+0x365/0x660 fs/splice.c:991
 do_splice_direct+0xf2/0x170 fs/splice.c:1079
 do_sendfile+0x56a/0xba0 fs/read_write.c:1548
 __do_sys_sendfile64 fs/read_write.c:1603 [inline]
 __se_sys_sendfile64 fs/read_write.c:1595 [inline]
 __x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1595
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810a14d1c0 of 8 bytes by task 19984 on cpu 1:
 iput+0x2e/0x550 fs/inode.c:1668
 fsnotify_drop_object fs/notify/mark.c:222 [inline]
 fsnotify_put_mark+0x437/0x5e0 fs/notify/mark.c:258
 fsnotify_clear_marks_by_group+0x348/0x3e0 fs/notify/mark.c:764
 fsnotify_destroy_group+0x51/0x170 fs/notify/group.c:61
 fanotify_release+0x2c5/0x2e0 fs/notify/fanotify/fanotify_user.c:623
 __fput+0x246/0x4d0 fs/file_table.c:281
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:141
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:165 [inline]
 exit_to_user_mode_prepare+0x1b2/0x210 kernel/entry/common.c:192
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:267
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19984 Comm: syz-executor.2 Not tainted 5.9.0-rc8-syzkaller #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	2020/10/09 23:10	upstream	8a5f78d98c26	93817d89	.config	log	report			info