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BUG: KCSAN: data-race in d_alloc_parallel / d_set_d_op

read-write to 0xffff888106543180 of 4 bytes by task 4406 on cpu 1:
 d_set_d_op+0xfb/0x1f0 fs/dcache.c:1831
 proc_pident_instantiate+0x164/0x180 fs/proc/base.c:2712
 proc_pident_lookup+0x11d/0x190 fs/proc/base.c:2735
 proc_tgid_base_lookup+0x2b/0x40 fs/proc/base.c:3458
 __lookup_slow+0x18a/0x250 fs/namei.c:1793
 lookup_slow+0x3c/0x60 fs/namei.c:1810
 walk_component fs/namei.c:2114 [inline]
 link_path_walk+0x668/0x830 fs/namei.c:2479
 path_openat+0x1af/0x1fc0 fs/namei.c:3985
 do_filp_open+0x107/0x230 fs/namei.c:4016
 do_sys_openat2+0xab/0x120 fs/open.c:1428
 do_sys_open fs/open.c:1443 [inline]
 __do_sys_openat fs/open.c:1459 [inline]
 __se_sys_openat fs/open.c:1454 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1454
 x64_sys_call+0x2b30/0x2dc0 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 0xffff888106543180 of 4 bytes by task 4405 on cpu 0:
 d_in_lookup include/linux/dcache.h:390 [inline]
 d_wait_lookup fs/dcache.c:2488 [inline]
 d_alloc_parallel+0x5dc/0xc80 fs/dcache.c:2576
 __lookup_slow+0x8d/0x250 fs/namei.c:1778
 lookup_slow+0x3c/0x60 fs/namei.c:1810
 walk_component fs/namei.c:2114 [inline]
 link_path_walk+0x668/0x830 fs/namei.c:2479
 path_openat+0x1af/0x1fc0 fs/namei.c:3985
 do_filp_open+0x107/0x230 fs/namei.c:4016
 do_sys_openat2+0xab/0x120 fs/open.c:1428
 do_sys_open fs/open.c:1443 [inline]
 __do_sys_openat fs/open.c:1459 [inline]
 __se_sys_openat fs/open.c:1454 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1454
 x64_sys_call+0x2b30/0x2dc0 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: 4405 Comm: syz.0.291 Not tainted 6.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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