syzbot

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BUG: KCSAN: data-race in __dentry_kill / link_path_walk

write to 0xffff888106e42cc0 of 4 bytes by task 5573 on cpu 0:
 dentry_unlist fs/dcache.c:522 [inline]
 __dentry_kill+0x147/0x4e0 fs/dcache.c:578
 shrink_dentry_list+0x1bb/0x340 fs/dcache.c:1176
 shrink_dcache_sb+0x188/0x2d0 fs/dcache.c:1296
 reconfigure_super+0x2aa/0x4f0 fs/super.c:889
 do_remount fs/namespace.c:2639 [inline]
 path_mount+0x1442/0x1ce0 fs/namespace.c:3227
 do_mount fs/namespace.c:3248 [inline]
 __do_sys_mount fs/namespace.c:3456 [inline]
 __se_sys_mount+0x23d/0x2e0 fs/namespace.c:3433
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3433
 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 0xffff888106e42cc0 of 4 bytes by task 1 on cpu 1:
 link_path_walk+0x384/0x770 fs/namei.c:2248
 path_openat+0x1a0/0x1f20 fs/namei.c:3503
 do_filp_open+0xe9/0x200 fs/namei.c:3534
 do_sys_openat2+0xa3/0x250 fs/open.c:1204
 do_sys_open fs/open.c:1220 [inline]
 __do_sys_open fs/open.c:1228 [inline]
 __se_sys_open fs/open.c:1224 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1224
 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: 0x00200000 -> 0x00008000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1 Comm: systemd Not tainted 5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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