syzbot

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BUG: KCSAN: data-race in list_lru_add / list_lru_count_one

write to 0xffff88821b20f998 of 8 bytes by task 2464 on cpu 0:
 list_lru_add+0x1e4/0x270 mm/list_lru.c:127
 workingset_update_node+0xc2/0xe0 mm/workingset.c:438
 xas_update lib/xarray.c:350 [inline]
 update_node lib/xarray.c:751 [inline]
 xas_store+0x863/0xd00 lib/xarray.c:838
 page_cache_delete mm/filemap.c:137 [inline]
 __delete_from_page_cache+0x22c/0x390 mm/filemap.c:238
 __remove_mapping+0x384/0x430 mm/vmscan.c:932
 shrink_page_list+0x1409/0x23a0 mm/vmscan.c:1437
 shrink_inactive_list+0x27d/0x610 mm/vmscan.c:1964
 shrink_list mm/vmscan.c:2173 [inline]
 shrink_lruvec+0x38a/0x620 mm/vmscan.c:2467
 shrink_node_memcgs+0x1be/0x360 mm/vmscan.c:2656
 shrink_node+0x94e/0x1170 mm/vmscan.c:2770
 kswapd_shrink_node mm/vmscan.c:3517 [inline]
 balance_pgdat+0x675/0xbb0 mm/vmscan.c:3675
 kswapd+0x1ef/0x370 mm/vmscan.c:3932
 kthread+0x20d/0x230 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

read to 0xffff88821b20f998 of 8 bytes by task 2463 on cpu 1:
 list_lru_count_one+0xb6/0xd0 mm/list_lru.c:183
 list_lru_shrink_count include/linux/list_lru.h:123 [inline]
 count_shadow_nodes+0x45/0x3c0 mm/workingset.c:456
 do_shrink_slab+0x86/0x5c0 mm/vmscan.c:436
 shrink_slab+0xea/0x1c0 mm/vmscan.c:679
 shrink_node_memcgs+0x1f9/0x360 mm/vmscan.c:2658
 shrink_node+0x94e/0x1170 mm/vmscan.c:2770
 kswapd_shrink_node mm/vmscan.c:3517 [inline]
 balance_pgdat+0x675/0xbb0 mm/vmscan.c:3675
 kswapd+0x1ef/0x370 mm/vmscan.c:3932
 kthread+0x20d/0x230 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2463 Comm: kswapd0 Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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