syzbot

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BUG: KCSAN: data-race in dont_mount / step_into

read-write to 0xffff888124f62a80 of 4 bytes by task 1915 on cpu 1:
 dont_mount+0x27/0x40 include/linux/dcache.h:348
 vfs_unlink+0x267/0x3d0 fs/namei.c:4151
 do_unlinkat+0x258/0x510 fs/namei.c:4217
 __do_sys_unlink fs/namei.c:4265 [inline]
 __se_sys_unlink fs/namei.c:4263 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:4263
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

read to 0xffff888124f62a80 of 4 bytes by task 1445 on cpu 0:
 __d_entry_type include/linux/dcache.h:385 [inline]
 d_is_symlink include/linux/dcache.h:415 [inline]
 step_into+0x12b/0x760 fs/namei.c:1855
 walk_component+0x19a/0x280 fs/namei.c:2027
 lookup_last fs/namei.c:2476 [inline]
 path_lookupat+0x11d/0x2b0 fs/namei.c:2500
 filename_lookup+0x130/0x310 fs/namei.c:2529
 user_path_at_empty+0x3e/0x110 fs/namei.c:2852
 do_readlinkat+0x98/0x210 fs/stat.c:456
 __do_sys_readlink fs/stat.c:489 [inline]
 __se_sys_readlink fs/stat.c:486 [inline]
 __x64_sys_readlink+0x43/0x50 fs/stat.c:486
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

value changed: 0x00600008 -> 0x00008008

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1445 Comm: udevd Tainted: G        W         5.18.0-syzkaller-10037-g7e284070abe5-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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