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BUG: KCSAN: data-race in d_alloc_parallel / d_set_d_op

write to 0xffff888105cd8f00 of 4 bytes by task 2576 on cpu 1:
 d_set_d_op+0x17f/0x220 fs/dcache.c:1908
 simple_lookup+0x78/0x90 fs/libfs.c:74
 __lookup_slow+0x181/0x280 fs/namei.c:1630
 lookup_slow fs/namei.c:1647 [inline]
 walk_component+0x2a5/0x350 fs/namei.c:1943
 lookup_last fs/namei.c:2398 [inline]
 path_lookupat+0x12d/0x570 fs/namei.c:2422
 filename_lookup+0xff/0x390 fs/namei.c:2455
 user_path_at_empty+0x3b/0x50 fs/namei.c:2735
 user_path_at include/linux/namei.h:60 [inline]
 vfs_statx+0x98/0x290 fs/stat.c:195
 vfs_fstatat fs/stat.c:217 [inline]
 vfs_stat include/linux/fs.h:3236 [inline]
 __do_sys_newstat fs/stat.c:359 [inline]
 __se_sys_newstat+0x46/0x250 fs/stat.c:355
 __x64_sys_newstat+0x2d/0x40 fs/stat.c:355
 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888105cd8f00 of 4 bytes by task 2579 on cpu 0:
 d_in_lookup include/linux/dcache.h:365 [inline]
 d_wait_lookup fs/dcache.c:2554 [inline]
 d_alloc_parallel+0x4ff/0xba0 fs/dcache.c:2642
 __lookup_slow+0x7f/0x280 fs/namei.c:1615
 lookup_slow fs/namei.c:1647 [inline]
 walk_component+0x2a5/0x350 fs/namei.c:1943
 lookup_last fs/namei.c:2398 [inline]
 path_lookupat+0x12d/0x570 fs/namei.c:2422
 filename_lookup+0xff/0x390 fs/namei.c:2455
 user_path_at_empty+0x3b/0x50 fs/namei.c:2735
 user_path_at include/linux/namei.h:60 [inline]
 vfs_statx+0x98/0x290 fs/stat.c:195
 vfs_fstatat fs/stat.c:217 [inline]
 vfs_stat include/linux/fs.h:3236 [inline]
 __do_sys_newstat fs/stat.c:359 [inline]
 __se_sys_newstat+0x46/0x250 fs/stat.c:355
 __x64_sys_newstat+0x2d/0x40 fs/stat.c:355
 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2579 Comm: modprobe Not tainted 5.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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