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BUG: KCSAN: data-race in d_alloc_parallel / d_set_d_op

read-write to 0xffff88811f0c9c00 of 4 bytes by task 18080 on cpu 1:
 d_set_d_op+0xf0/0x1e0 fs/dcache.c:1932
 proc_pident_instantiate+0x164/0x180 fs/proc/base.c:2656
 proc_pident_lookup fs/proc/base.c:2679 [inline]
 proc_tgid_base_lookup+0x10c/0x180 fs/proc/base.c:3376
 __lookup_slow+0x178/0x230 fs/namei.c:1685
 lookup_slow+0x3c/0x60 fs/namei.c:1702
 walk_component fs/namei.c:1993 [inline]
 link_path_walk+0x69b/0x8a0 fs/namei.c:2320
 path_openat+0x19d/0x1b60 fs/namei.c:3710
 do_filp_open+0x105/0x220 fs/namei.c:3741
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1310
 do_sys_open fs/open.c:1326 [inline]
 __do_sys_openat fs/open.c:1342 [inline]
 __se_sys_openat fs/open.c:1337 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88811f0c9c00 of 4 bytes by task 18081 on cpu 0:
 d_in_lookup include/linux/dcache.h:359 [inline]
 d_wait_lookup fs/dcache.c:2619 [inline]
 d_alloc_parallel+0x5f5/0xc30 fs/dcache.c:2707
 __lookup_slow+0x7d/0x230 fs/namei.c:1670
 lookup_slow+0x3c/0x60 fs/namei.c:1702
 walk_component fs/namei.c:1993 [inline]
 link_path_walk+0x69b/0x8a0 fs/namei.c:2320
 path_openat+0x19d/0x1b60 fs/namei.c:3710
 do_filp_open+0x105/0x220 fs/namei.c:3741
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1310
 do_sys_open fs/open.c:1326 [inline]
 __do_sys_openat fs/open.c:1342 [inline]
 __se_sys_openat fs/open.c:1337 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x10000000 -> 0x1000000c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18081 Comm: syz-executor.5 Not tainted 6.2.0-rc5-syzkaller-00020-g7bf70dbb1882-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
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