syzbot

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BUG: KCSAN: data-race in dentry_lru_isolate / path_openat

write to 0xffff888120537d80 of 4 bytes by task 2486 on cpu 1:
 d_lru_isolate fs/dcache.c:442 [inline]
 dentry_lru_isolate+0x9f/0x200 fs/dcache.c:1166
 __list_lru_walk_one+0xfb/0x320 mm/list_lru.c:222
 list_lru_walk_one+0x75/0x90 mm/list_lru.c:266
 list_lru_shrink_walk include/linux/list_lru.h:195 [inline]
 prune_dcache_sb+0x67/0xa0 fs/dcache.c:1220
 super_cache_scan+0x23b/0x2d0 fs/super.c:105
 do_shrink_slab+0x286/0x5c0 mm/vmscan.c:513
 shrink_slab+0xea/0x1c0 mm/vmscan.c:674
 shrink_node_memcgs+0x270/0x410 mm/vmscan.c:2645
 shrink_node+0x9ed/0x1230 mm/vmscan.c:2760
 kswapd_shrink_node mm/vmscan.c:3503 [inline]
 balance_pgdat+0x675/0xc20 mm/vmscan.c:3661
 kswapd+0x1ef/0x370 mm/vmscan.c:3918
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff888120537d80 of 4 bytes by task 5073 on cpu 0:
 __d_entry_type include/linux/dcache.h:391 [inline]
 d_can_lookup include/linux/dcache.h:406 [inline]
 do_open fs/namei.c:3234 [inline]
 path_openat+0x1671/0x20a0 fs/namei.c:3368
 do_filp_open+0xbd/0x1d0 fs/namei.c:3395
 do_sys_openat2+0x33b/0x500 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_sys_open fs/open.c:1192 [inline]
 __se_sys_open fs/open.c:1188 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1188
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5073 Comm: systemd-udevd Not tainted 5.9.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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