syzbot

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BUG: KCSAN: data-race in d_delete / lookup_fast

read-write to 0xffff88810656aa80 of 4 bytes by task 3287 on cpu 0:
 d_delete+0x15a/0x180 fs/dcache.c:2433
 d_delete_notify+0x34/0x100 include/linux/fsnotify.h:395
 vfs_unlink+0x320/0x430 fs/namei.c:4540
 do_unlinkat+0x237/0x4d0 fs/namei.c:4589
 __do_sys_unlink fs/namei.c:4637 [inline]
 __se_sys_unlink fs/namei.c:4635 [inline]
 __x64_sys_unlink+0x2e/0x40 fs/namei.c:4635
 x64_sys_call+0x2329/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:88
 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 0xffff88810656aa80 of 4 bytes by task 3000 on cpu 1:
 d_revalidate fs/namei.c:927 [inline]
 lookup_fast+0xe9/0x320 fs/namei.c:1741
 walk_component+0x3f/0x230 fs/namei.c:2110
 lookup_last fs/namei.c:2612 [inline]
 path_lookupat+0x10a/0x2b0 fs/namei.c:2636
 filename_lookup+0x150/0x340 fs/namei.c:2665
 do_readlinkat+0x89/0x210 fs/stat.c:564
 __do_sys_readlink fs/stat.c:601 [inline]
 __se_sys_readlink fs/stat.c:598 [inline]
 __x64_sys_readlink+0x47/0x60 fs/stat.c:598
 x64_sys_call+0x28ba/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:90
 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: 0x00600108 -> 0x00008008

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3000 Comm: udevd Not tainted 6.14.0-rc7-syzkaller-00050-gfc444ada1310 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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