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BUG: KCSAN: data-race in __dentry_kill / fast_dput

write to 0xffff8881158c8b50 of 8 bytes by task 4450 on cpu 0:
 __d_drop fs/dcache.c:531 [inline]
 __dentry_kill+0x13e/0x4c0 fs/dcache.c:623
 dput+0x5c/0xd0 fs/dcache.c:867
 handle_mounts fs/namei.c:1638 [inline]
 step_into+0x21a/0x840 fs/namei.c:1950
 open_last_lookups fs/namei.c:3775 [inline]
 path_openat+0x1234/0x1fa0 fs/namei.c:3984
 do_filp_open+0x107/0x230 fs/namei.c:4014
 do_sys_openat2+0xab/0x120 fs/open.c:1402
 do_sys_open fs/open.c:1417 [inline]
 __do_sys_openat fs/open.c:1433 [inline]
 __se_sys_openat fs/open.c:1428 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1428
 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 0xffff8881158c8b50 of 8 bytes by task 3372 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:708 [inline]
 fast_dput+0x65/0x2c0 fs/dcache.c:804
 dput+0x24/0xd0 fs/dcache.c:861
 handle_mounts fs/namei.c:1638 [inline]
 step_into+0x21a/0x840 fs/namei.c:1950
 open_last_lookups fs/namei.c:3775 [inline]
 path_openat+0x1234/0x1fa0 fs/namei.c:3984
 do_filp_open+0x107/0x230 fs/namei.c:4014
 do_sys_openat2+0xab/0x120 fs/open.c:1402
 do_sys_open fs/open.c:1417 [inline]
 __do_sys_openat fs/open.c:1433 [inline]
 __se_sys_openat fs/open.c:1428 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1428
 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: 0xffff8882376e89f8 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3372 Comm: udevd Not tainted 6.13.0-rc3-syzkaller-00017-gf44d154d6e3d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
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