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BUG: KCSAN: data-race in __d_rehash / fast_dput

write to 0xffff888105ced250 of 8 bytes by task 3262 on cpu 0:
 hlist_bl_add_head_rcu include/linux/rculist_bl.h:81 [inline]
 __d_rehash+0xa9/0x210 fs/dcache.c:2412
 __d_add+0x373/0x4a0 fs/dcache.c:2627
 d_splice_alias+0xd6/0x270 fs/dcache.c:3018
 proc_sys_lookup+0x386/0x440 fs/proc/proc_sysctl.c:534
 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+0x1ac/0x2e00 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 0xffff888105ced250 of 8 bytes by task 3263 on cpu 1:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:354 [inline]
 retain_dentry fs/dcache.c:693 [inline]
 fast_dput+0x65/0x2c0 fs/dcache.c:789
 dput+0x24/0xd0 fs/dcache.c:846
 __fput+0x41f/0x6f0 fs/file_table.c:430
 __fput_sync+0x44/0x60 fs/file_table.c:507
 __do_sys_close fs/open.c:1566 [inline]
 __se_sys_close+0x101/0x1b0 fs/open.c:1551
 __x64_sys_close+0x1f/0x30 fs/open.c:1551
 x64_sys_call+0x2630/0x2e00 arch/x86/include/generated/asm/syscalls_64.h:4
 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: 0xffff888237a87388 -> 0xffff888105c86488

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3263 Comm: syz-executor Not tainted 6.11.0-rc1-syzkaller-00151-g183d46ff422e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
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