KCSAN: data-race in __dentry_kill / d_lru

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __dentry_kill / d_lru_del fs				1	1913d	1913d	0/28	closed as invalid on 2019/11/19 13:24
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BUG: KCSAN: data-race in __dentry_kill / d_lru_del

read to 0xffff8881256f6c00 of 4 bytes by task 8368 on cpu 1:
 dentry_unlist fs/dcache.c:544 [inline]
 __dentry_kill+0x1be/0x3c0 fs/dcache.c:575
 dentry_kill fs/dcache.c:698 [inline]
 dput+0x3b5/0x750 fs/dcache.c:859
 path_put_conditional fs/namei.c:821 [inline]
 follow_managed+0x1eb/0x6f0 fs/namei.c:1279
 walk_component+0x4ec/0xd90 fs/namei.c:1808
 lookup_last fs/namei.c:2260 [inline]
 path_lookupat.isra.0+0x13a/0x5a0 fs/namei.c:2305
 filename_lookup+0x145/0x2b0 fs/namei.c:2335
 user_path_at_empty+0x4c/0x70 fs/namei.c:2615
 do_readlinkat+0x84/0x220 fs/stat.c:399
 __do_sys_readlink fs/stat.c:432 [inline]
 __se_sys_readlink fs/stat.c:429 [inline]
 __x64_sys_readlink+0x51/0x70 fs/stat.c:429
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8881256f6c00 of 4 bytes by task 20685 on cpu 0:
 d_lru_del+0x5d/0xf0 fs/dcache.c:410
 __dput_to_list+0xe9/0xf0 fs/dcache.c:872
 shrink_dentry_list+0x101/0x1c0 fs/dcache.c:1121
 shrink_dcache_parent+0x1ef/0x280 fs/dcache.c:1549
 d_invalidate fs/dcache.c:1658 [inline]
 d_invalidate+0x85/0x180 fs/dcache.c:1643
 lookup_fast+0x58f/0x6c0 fs/namei.c:1622
 walk_component+0x6d/0xd90 fs/namei.c:1798
 lookup_last fs/namei.c:2260 [inline]
 path_lookupat.isra.0+0x13a/0x5a0 fs/namei.c:2305
 filename_lookup+0x145/0x2b0 fs/namei.c:2335
 user_path_at_empty+0x4c/0x70 fs/namei.c:2615
 do_readlinkat+0x84/0x220 fs/stat.c:399
 __do_sys_readlink fs/stat.c:432 [inline]
 __se_sys_readlink fs/stat.c:429 [inline]
 __x64_sys_readlink+0x51/0x70 fs/stat.c:429
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 20685 Comm: udevd Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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