KCSAN: data-race in __fsnotify_parent / vfs

KCSAN: data-race in __fsnotify_parent / vfs_rename
Status: moderation: reported on 2020/12/07 11:39
Reported-by: syzbot+7accc0b9c3e3b924a735@syzkaller.appspotmail.com
First crash: 127d, last: 21h13m

Sample crash report:

==================================================================
BUG: KCSAN: data-race in __fsnotify_parent / vfs_rename

read-write to 0xffff88810d9fba80 of 4 bytes by task 10687 on cpu 1:
 dont_mount include/linux/dcache.h:355 [inline]
 vfs_rename+0xcd9/0xe20 fs/namei.c:4322
 do_renameat2+0x5c3/0x900 fs/namei.c:4457
 __do_sys_rename fs/namei.c:4508 [inline]
 __se_sys_rename fs/namei.c:4506 [inline]
 __x64_sys_rename+0x58/0x60 fs/namei.c:4506
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810d9fba80 of 4 bytes by task 4892 on cpu 0:
 __fsnotify_parent+0x7d/0x430 fs/notify/fsnotify.c:187
 fsnotify_parent include/linux/fsnotify.h:68 [inline]
 fsnotify_file include/linux/fsnotify.h:90 [inline]
 fsnotify_perm+0x296/0x2d0 include/linux/fsnotify.h:115
 security_file_permission+0x87/0xa0 security/security.c:1452
 rw_verify_area+0x136/0x250 fs/read_write.c:400
 vfs_read+0xde/0x5c0 fs/read_write.c:487
 ksys_read+0xce/0x180 fs/read_write.c:634
 __do_sys_read fs/read_write.c:644 [inline]
 __se_sys_read fs/read_write.c:642 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:642
 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: 4892 Comm: systemd-udevd Not tainted 5.11.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (13):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Maintainers
ci2-upstream-kcsan-gce	2021/01/24 11:15	upstream	e1ae4b0b	52e37319	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/13 04:14	upstream	e609571b	0cdd6185	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/12 00:15	upstream	a0d54b4f	2c1f2513	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/11 02:26	upstream	9fca90cf	f900b48c	.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 14:57	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 00:05	upstream	b6505459	c42a35e9	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/13 09:36	upstream	af5043c8	16fca0c8	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/07 17:18	upstream	659caaf6	cba33199	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/10/22 01:39	upstream	f804b315	be6b1582	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/10/14 22:37	upstream	b5fc7a89	fc7735a2	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/10/01 22:30	upstream	fcadab74	9602ddf4	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/09/22 19:29	upstream	eff48dde	3e8f6c27	.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 15:37	upstream	eb5f95f1	53ce8104	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk