KCSAN: data-race in ___d_drop / __d_lookup

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in ___d_drop / __d_lookup_rcu (2) fs				1	464d	464d	0/28	auto-obsoleted due to no activity on 2024/02/14 17:51

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BUG: KCSAN: data-race in ___d_drop / __d_lookup_rcu

read to 0xffff8881024b3610 of 8 bytes by task 28486 on cpu 1:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:335 [inline]
 __d_lookup_rcu+0x120/0x290 fs/dcache.c:2400
 lookup_fast+0x8e/0x290 fs/namei.c:1625
 walk_component fs/namei.c:1994 [inline]
 link_path_walk+0x3f4/0x7e0 fs/namei.c:2325
 path_lookupat+0x72/0x2a0 fs/namei.c:2478
 filename_lookup+0x126/0x300 fs/namei.c:2508
 vfs_statx+0xa9/0x300 fs/stat.c:238
 vfs_fstatat fs/stat.c:276 [inline]
 __do_sys_newfstatat fs/stat.c:446 [inline]
 __se_sys_newfstatat+0x8a/0x2a0 fs/stat.c:440
 __x64_sys_newfstatat+0x55/0x60 fs/stat.c:440
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

write to 0xffff8881024b3610 of 8 bytes by task 3070 on cpu 0:
 __hlist_bl_del include/linux/list_bl.h:128 [inline]
 ___d_drop+0x106/0x220 fs/dcache.c:500
 __d_drop fs/dcache.c:507 [inline]
 __dentry_kill+0x147/0x4a0 fs/dcache.c:602
 dentry_kill+0x8d/0x1e0
 dput+0x118/0x1f0 fs/dcache.c:913
 handle_mounts fs/namei.c:1551 [inline]
 step_into+0x21a/0x800 fs/namei.c:1836
 open_last_lookups fs/namei.c:3583 [inline]
 path_openat+0x10af/0x1d00 fs/namei.c:3788
 do_filp_open+0xf6/0x200 fs/namei.c:3818
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1356
 do_sys_open fs/open.c:1372 [inline]
 __do_sys_openat fs/open.c:1388 [inline]
 __se_sys_openat fs/open.c:1383 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1383
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3070 Comm: syz-executor.2 Not tainted 6.4.0-rc6-syzkaller-00242-g1639fae5132b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
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