syzbot

BUG: KCSAN: data-race in dont_mount / step_into

read-write to 0xffff88810ae603c0 of 4 bytes by task 5401 on cpu 0:
 dont_mount+0x27/0x40 include/linux/dcache.h:351
 vfs_unlink+0x27e/0x3e0 fs/namei.c:4254
 do_unlinkat+0x258/0x510 fs/namei.c:4320
 __do_sys_unlink fs/namei.c:4368 [inline]
 __se_sys_unlink fs/namei.c:4366 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:4366
 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+0x63/0xcd

read to 0xffff88810ae603c0 of 4 bytes by task 2737 on cpu 1:
 __follow_mount_rcu fs/namei.c:1480 [inline]
 handle_mounts fs/namei.c:1531 [inline]
 step_into+0xdc/0x7d0 fs/namei.c:1831
 walk_component+0x164/0x230 fs/namei.c:1999
 lookup_last fs/namei.c:2450 [inline]
 path_lookupat+0x11d/0x2b0 fs/namei.c:2474
 filename_lookup+0x133/0x310 fs/namei.c:2503
 user_path_at_empty+0x3e/0x110 fs/namei.c:2876
 do_readlinkat+0x98/0x210 fs/stat.c:471
 __do_sys_readlink fs/stat.c:504 [inline]
 __se_sys_readlink fs/stat.c:501 [inline]
 __x64_sys_readlink+0x43/0x50 fs/stat.c:501
 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+0x63/0xcd

value changed: 0x00600008 -> 0x00008008

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2737 Comm: udevd Not tainted 6.2.0-rc6-syzkaller-00050-g9f266ccaa2f5-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
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