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BUG: KCSAN: data-race in d_alloc_parallel / d_set_d_op

read-write to 0xffff88810692c6c0 of 4 bytes by task 7776 on cpu 1:
 d_set_d_op+0xfb/0x1f0 fs/dcache.c:1799
 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:3556 [inline]
 open_last_lookups fs/namei.c:3647 [inline]
 path_openat+0xc5f/0x1f10 fs/namei.c:3883
 do_filp_open+0xf7/0x200 fs/namei.c:3913
 do_sys_openat2+0xab/0x120 fs/open.c:1416
 do_sys_open fs/open.c:1431 [inline]
 __do_sys_openat fs/open.c:1447 [inline]
 __se_sys_openat fs/open.c:1442 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1442
 x64_sys_call+0x1025/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810692c6c0 of 4 bytes by task 7775 on cpu 0:
 d_in_lookup include/linux/dcache.h:378 [inline]
 d_wait_lookup fs/dcache.c:2452 [inline]
 d_alloc_parallel+0x60b/0xc80 fs/dcache.c:2540
 lookup_open fs/namei.c:3503 [inline]
 open_last_lookups fs/namei.c:3647 [inline]
 path_openat+0x674/0x1f10 fs/namei.c:3883
 do_filp_open+0xf7/0x200 fs/namei.c:3913
 do_sys_openat2+0xab/0x120 fs/open.c:1416
 do_sys_open fs/open.c:1431 [inline]
 __do_sys_openat fs/open.c:1447 [inline]
 __se_sys_openat fs/open.c:1442 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1442
 x64_sys_call+0x1025/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x10000000 -> 0x1000000c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 7775 Comm: syz.3.1172 Not tainted 6.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
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