KCSAN: data-race in link_path_walk / vfs

KCSAN: data-race in link_path_walk / vfs_rmdir
Status: auto-closed as invalid on 2020/09/11 12:18
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 359d, last: 359d

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in link_path_walk / vfs_rmdir (2)				1	80d	80d	0/22	auto-closed as invalid on 2021/06/17 14:31

Sample crash report:

==================================================================
BUG: KCSAN: data-race in link_path_walk / vfs_rmdir

write to 0xffff888115c13c00 of 4 bytes by task 13937 on cpu 0:
 dont_mount include/linux/dcache.h:354 [inline]
 vfs_rmdir+0x1a6/0x2a0 fs/namei.c:3710
 do_rmdir+0x170/0x320 fs/namei.c:3766
 __do_sys_rmdir fs/namei.c:3784 [inline]
 __se_sys_rmdir fs/namei.c:3782 [inline]
 __x64_sys_rmdir+0x20/0x30 fs/namei.c:3782
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888115c13c00 of 4 bytes by task 13942 on cpu 1:
 __d_entry_type include/linux/dcache.h:391 [inline]
 d_can_lookup include/linux/dcache.h:406 [inline]
 link_path_walk+0x47e/0x730 fs/namei.c:2193
 path_lookupat+0x7b/0x560 fs/namei.c:2332
 filename_lookup+0xf2/0x380 fs/namei.c:2366
 user_path_at_empty+0x3b/0x50 fs/namei.c:2646
 do_readlinkat+0x87/0x200 fs/stat.c:419
 __do_sys_readlink fs/stat.c:452 [inline]
 __se_sys_readlink fs/stat.c:449 [inline]
 __x64_sys_readlink+0x43/0x50 fs/stat.c:449
 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: 13942 Comm: systemd-udevd Not tainted 5.8.0-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	2020/08/07 12:10	upstream	86cfccb66937	28ac5c9e	.config	log	report