syzbot

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BUG: KCSAN: data-race in d_invalidate / fast_dput

write to 0xffff88813008a610 of 8 bytes by task 4934 on cpu 1:
 __d_drop fs/dcache.c:521 [inline]
 d_invalidate+0x5c/0x1c0 fs/dcache.c:1597
 lookup_fast+0x254/0x2a0 fs/namei.c:1697
 walk_component fs/namei.c:2049 [inline]
 link_path_walk+0x464/0x820 fs/namei.c:2418
 path_openat+0x1af/0x1fa0 fs/namei.c:3929
 do_filp_open+0xf7/0x200 fs/namei.c:3960
 do_sys_openat2+0xab/0x120 fs/open.c:1415
 do_sys_open fs/open.c:1430 [inline]
 __do_sys_openat fs/open.c:1446 [inline]
 __se_sys_openat fs/open.c:1441 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1441
 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 0xffff88813008a610 of 8 bytes by task 4932 on cpu 0:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:354 [inline]
 retain_dentry fs/dcache.c:698 [inline]
 fast_dput+0x65/0x2c0 fs/dcache.c:794
 dput+0x24/0xd0 fs/dcache.c:851
 handle_mounts fs/namei.c:1579 [inline]
 step_into+0x21a/0x810 fs/namei.c:1891
 walk_component fs/namei.c:2059 [inline]
 link_path_walk+0x54c/0x820 fs/namei.c:2418
 path_openat+0x1af/0x1fa0 fs/namei.c:3929
 do_filp_open+0xf7/0x200 fs/namei.c:3960
 do_sys_openat2+0xab/0x120 fs/open.c:1415
 do_sys_open fs/open.c:1430 [inline]
 __do_sys_openat fs/open.c:1446 [inline]
 __se_sys_openat fs/open.c:1441 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1441
 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: 0xffff8882374fa170 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4932 Comm: udevd Not tainted 6.12.0-rc6-syzkaller-00279-gde2f378f2b77 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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