syzbot

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BUG: KCSAN: data-race in step_into / vfs_rename

write to 0xffff888106f5d6c0 of 4 bytes by task 6533 on cpu 0:
 dont_mount include/linux/dcache.h:358 [inline]
 vfs_rename+0xe4a/0xfb0 fs/namei.c:4561
 do_renameat2+0x59e/0x9b0 fs/namei.c:4706
 __do_sys_rename fs/namei.c:4755 [inline]
 __se_sys_rename fs/namei.c:4753 [inline]
 __x64_sys_rename+0x58/0x60 fs/namei.c:4753
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888106f5d6c0 of 4 bytes by task 1 on cpu 1:
 __follow_mount_rcu fs/namei.c:1418 [inline]
 handle_mounts fs/namei.c:1475 [inline]
 step_into+0xfe/0xee0 fs/namei.c:1789
 walk_component+0x190/0x350 fs/namei.c:1965
 lookup_last fs/namei.c:2414 [inline]
 path_lookupat+0x12d/0x3d0 fs/namei.c:2438
 filename_lookup+0x118/0x3b0 fs/namei.c:2467
 user_path_at_empty+0x3b/0x50 fs/namei.c:2747
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0x98/0x290 fs/stat.c:203
 vfs_fstatat fs/stat.c:225 [inline]
 vfs_stat include/linux/fs.h:3382 [inline]
 __do_sys_newstat fs/stat.c:367 [inline]
 __se_sys_newstat+0x46/0x250 fs/stat.c:363
 __x64_sys_newstat+0x2d/0x40 fs/stat.c:363
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00600008 -> 0x00008108

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1 Comm: systemd Not tainted 5.14.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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