syzbot

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BUG: KCSAN: data-race in __dentry_kill / vfs_unlink

write to 0xffff8881059a2240 of 4 bytes by task 16750 on cpu 1:
 dont_mount include/linux/dcache.h:358 [inline]
 vfs_unlink+0x296/0x450 fs/namei.c:4102
 do_unlinkat+0x278/0x540 fs/namei.c:4167
 __do_sys_unlink fs/namei.c:4215 [inline]
 __se_sys_unlink fs/namei.c:4213 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:4213
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881059a2240 of 4 bytes by task 1439 on cpu 0:
 dentry_unlist fs/dcache.c:547 [inline]
 __dentry_kill+0x1ef/0x450 fs/dcache.c:578
 dput+0x218/0x430 fs/dcache.c:888
 handle_mounts fs/namei.c:1502 [inline]
 step_into+0x468/0xee0 fs/namei.c:1800
 walk_component+0x1a1/0x360 fs/namei.c:1976
 lookup_last fs/namei.c:2425 [inline]
 path_lookupat+0x12d/0x3d0 fs/namei.c:2449
 filename_lookup+0x130/0x310 fs/namei.c:2478
 user_path_at_empty+0x3e/0x110 fs/namei.c:2801
 do_readlinkat+0x97/0x210 fs/stat.c:443
 __do_sys_readlink fs/stat.c:476 [inline]
 __se_sys_readlink fs/stat.c:473 [inline]
 __x64_sys_readlink+0x43/0x50 fs/stat.c:473
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00600008 -> 0x00000008

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1439 Comm: udevd Tainted: G        W         5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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