KCSAN: data-race in __ext4_update_other_inode

KCSAN: data-race in __ext4_update_other_inode_time / iput (2)
Status: moderation: reported on 2020/12/07 11:39
Reported-by: syzbot+b8d0ddf36fbf69a1e066@syzkaller.appspotmail.com
First crash: 123d, last: 16d

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __ext4_update_other_inode_time / iput				5	161d	211d	0/17	auto-closed as invalid on 2020/09/21 07:31

Sample crash report:

==================================================================
BUG: KCSAN: data-race in __ext4_update_other_inode_time / iput

write to 0xffff88801491a678 of 8 bytes by task 31983 on cpu 0:
 __ext4_update_other_inode_time+0xc1/0x550 fs/ext4/inode.c:4975
 ext4_update_other_inodes_time fs/ext4/inode.c:5011 [inline]
 ext4_do_update_inode fs/ext4/inode.c:5140 [inline]
 ext4_mark_iloc_dirty+0x1286/0x1650 fs/ext4/inode.c:5721
 __ext4_mark_inode_dirty+0x4cd/0x5d0 fs/ext4/inode.c:5915
 ext4_ext_tree_init+0x7e/0x90 fs/ext4/extents.c:828
 __ext4_new_inode+0x2a90/0x3060 fs/ext4/ialloc.c:1326
 ext4_symlink+0x2bc/0x780 fs/ext4/namei.c:3330
 vfs_symlink+0x216/0x2d0 fs/namei.c:3962
 do_symlinkat+0xee/0x280 fs/namei.c:3989
 __do_sys_symlink fs/namei.c:4008 [inline]
 __se_sys_symlink fs/namei.c:4006 [inline]
 __x64_sys_symlink+0x32/0x40 fs/namei.c:4006
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88801491a678 of 8 bytes by task 8473 on cpu 1:
 iput+0x2e/0x510 fs/inode.c:1669
 do_unlinkat+0x2c9/0x4d0 fs/namei.c:3905
 __do_sys_unlink fs/namei.c:3945 [inline]
 __se_sys_unlink fs/namei.c:3943 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:3943
 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: 8473 Comm: syz-executor.1 Not tainted 5.11.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (15):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Maintainers
ci2-upstream-kcsan-gce	2021/01/09 05:03	upstream	6279d812	c104d4a3	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2021/01/08 04:01	upstream	f5e6c330	c104d4a3	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/30 05:05	upstream	139711f0	0fa352f2	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/27 21:46	upstream	f838f8d2	2242f77f	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/23 05:51	upstream	614cb589	04201c06	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/13 19:49	upstream	6bff9bb8	8f160dd5	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/12/12 01:35	upstream	7f376f19	bca53db9	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/11/18 14:32	upstream	0fa8ee0d	09323409	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/11/10 11:15	upstream	407ab579	cca87986	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/11/03 15:45	upstream	b7cbaf59	cba33199	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/10/31 16:56	upstream	5fc6b075	8bc4594f	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/10/23 23:52	upstream	0adc313c	2bb6666c	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/10/13 21:27	upstream	6ad4bf6e	fc7735a2	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/09/27 20:26	upstream	a1bffa48	5dd8aee8	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu
ci2-upstream-kcsan-gce	2020/09/24 01:49	upstream	c9c9e6a4	54289b08	.config	log	report	info	adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, tytso@mit.edu