KCSAN: data-race in __ext4_unlink / __ext4_update_other_inode

KCSAN: data-race in __ext4_unlink / __ext4_update_other_inode_time (2)
Status: auto-closed as invalid on 2021/05/17 11:36
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 136d, last: 112d

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __ext4_unlink / __ext4_update_other_inode_time				9	200d	233d	0/22	auto-closed as invalid on 2021/02/13 03:24

Sample crash report:

==================================================================
BUG: KCSAN: data-race in __ext4_unlink / __ext4_update_other_inode_time

write to 0xffff888107183b80 of 8 bytes by task 12681 on cpu 1:
 __ext4_unlink+0x4e3/0x6c0 fs/ext4/namei.c:3250
 ext4_unlink+0x1f1/0x3f0 fs/ext4/namei.c:3285
 vfs_unlink+0x24a/0x3e0 fs/namei.c:4031
 do_unlinkat+0x29f/0x4f0 fs/namei.c:4098
 __do_sys_unlink fs/namei.c:4145 [inline]
 __se_sys_unlink fs/namei.c:4143 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:4143
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888107183b80 of 8 bytes by task 17802 on cpu 0:
 ext4_encode_extra_time fs/ext4/ext4.h:891 [inline]
 __ext4_update_other_inode_time+0x14f/0x550 fs/ext4/inode.c:4976
 ext4_update_other_inodes_time fs/ext4/inode.c:5008 [inline]
 ext4_do_update_inode fs/ext4/inode.c:5137 [inline]
 ext4_mark_iloc_dirty+0x1286/0x1700 fs/ext4/inode.c:5726
 __ext4_mark_inode_dirty+0x4db/0x5e0 fs/ext4/inode.c:5920
 ext4_ext_tree_init+0x7e/0x90 fs/ext4/extents.c:828
 __ext4_new_inode+0x29ff/0x2fe0 fs/ext4/ialloc.c:1327
 ext4_symlink+0x2d1/0x780 fs/ext4/namei.c:3347
 vfs_symlink+0xbe/0x170 fs/namei.c:4178
 do_symlinkat+0x11e/0x2b0 fs/namei.c:4208
 __do_sys_symlink fs/namei.c:4229 [inline]
 __se_sys_symlink fs/namei.c:4227 [inline]
 __x64_sys_symlink+0x32/0x40 fs/namei.c:4227
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17802 Comm: syz-executor.1 Tainted: G        W         5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2021/04/06 21:57	upstream	2d743660786e	6a81331a	.config	log	report			info	KCSAN: data-race in __ext4_unlink / __ext4_update_other_inode_time
ci2-upstream-kcsan-gce	2021/03/14 01:19	upstream	88fe49249c99	4a003785	.config	log	report			info	KCSAN: data-race in __ext4_unlink / __ext4_update_other_inode_time