syzbot

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BUG: KCSAN: data-race in dont_mount / step_into

read-write to 0xffff888109362c00 of 4 bytes by task 3337 on cpu 0:
 dont_mount+0x27/0x40 include/linux/dcache.h:363
 vfs_unlink+0x298/0x430 fs/namei.c:4345
 do_unlinkat+0x236/0x4c0 fs/namei.c:4407
 __do_sys_unlink fs/namei.c:4455 [inline]
 __se_sys_unlink fs/namei.c:4453 [inline]
 __x64_sys_unlink+0x30/0x40 fs/namei.c:4453
 x64_sys_call+0x28a3/0x2d70 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 0xffff888109362c00 of 4 bytes by task 2786 on cpu 1:
 __follow_mount_rcu fs/namei.c:1485 [inline]
 handle_mounts fs/namei.c:1536 [inline]
 step_into+0xe7/0x810 fs/namei.c:1842
 walk_component+0x169/0x230 fs/namei.c:2010
 lookup_last fs/namei.c:2469 [inline]
 path_lookupat+0x10a/0x2b0 fs/namei.c:2493
 filename_lookup+0x127/0x300 fs/namei.c:2522
 user_path_at_empty+0x42/0x120 fs/namei.c:2929
 do_readlinkat+0x92/0x210 fs/stat.c:499
 __do_sys_readlink fs/stat.c:532 [inline]
 __se_sys_readlink fs/stat.c:529 [inline]
 __x64_sys_readlink+0x47/0x60 fs/stat.c:529
 x64_sys_call+0x264b/0x2d70 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: 0x00600008 -> 0x00008008

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2786 Comm: udevd Not tainted 6.10.0-rc4-syzkaller-00045-g92e5605a199e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
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