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BUG: KCSAN: data-race in d_alloc_parallel / d_set_d_op

read-write to 0xffff888120806240 of 4 bytes by task 11483 on cpu 1:
 d_set_d_op+0xf4/0x1e0 fs/dcache.c:1931
 proc_ns_instantiate fs/proc/namespaces.c:114 [inline]
 proc_ns_dir_lookup+0x180/0x220 fs/proc/namespaces.c:172
 lookup_open fs/namei.c:3455 [inline]
 open_last_lookups fs/namei.c:3546 [inline]
 path_openat+0xc6f/0x1d70 fs/namei.c:3776
 do_filp_open+0xf6/0x200 fs/namei.c:3809
 do_sys_openat2+0xab/0x110 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888120806240 of 4 bytes by task 11484 on cpu 0:
 d_in_lookup include/linux/dcache.h:360 [inline]
 d_wait_lookup fs/dcache.c:2618 [inline]
 d_alloc_parallel+0x621/0xc90 fs/dcache.c:2706
 lookup_open fs/namei.c:3402 [inline]
 open_last_lookups fs/namei.c:3546 [inline]
 path_openat+0x658/0x1d70 fs/namei.c:3776
 do_filp_open+0xf6/0x200 fs/namei.c:3809
 do_sys_openat2+0xab/0x110 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x10000000 -> 0x1000000c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11484 Comm: syz-executor.5 Not tainted 6.7.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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