syzbot

==================================================================
BUG: KCSAN: data-race in __bpf_lru_list_shrink / __htab_lru_percpu_map_update_elem

write to 0xffff888096ef55ab of 1 bytes by task 15651 on cpu 0:
 bpf_lru_node_set_ref kernel/bpf/bpf_lru_list.h:70 [inline]
 __htab_lru_percpu_map_update_elem+0x6ea/0xa30 kernel/bpf/hashtab.c:1180
 bpf_percpu_hash_update+0x5a/0x90 kernel/bpf/hashtab.c:1902
 bpf_map_update_value+0x1d8/0x320 kernel/bpf/syscall.c:172
 generic_map_update_batch+0x336/0x450 kernel/bpf/syscall.c:1342
 bpf_map_do_batch+0x286/0x2f0 kernel/bpf/syscall.c:3870
 __do_sys_bpf+0xb2a/0x9a60 kernel/bpf/syscall.c:4242
 __se_sys_bpf kernel/bpf/syscall.c:4136 [inline]
 __x64_sys_bpf+0x3d/0x50 kernel/bpf/syscall.c:4136
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888096ef55ab of 1 bytes by task 15645 on cpu 1:
 bpf_lru_node_is_ref kernel/bpf/bpf_lru_list.c:44 [inline]
 __bpf_lru_list_shrink_inactive kernel/bpf/bpf_lru_list.c:218 [inline]
 __bpf_lru_list_shrink+0xbf/0x780 kernel/bpf/bpf_lru_list.c:266
 bpf_lru_list_pop_free_to_local kernel/bpf/bpf_lru_list.c:340 [inline]
 bpf_common_lru_pop_free kernel/bpf/bpf_lru_list.c:447 [inline]
 bpf_lru_pop_free+0x9f8/0xeb0 kernel/bpf/bpf_lru_list.c:499
 prealloc_lru_pop kernel/bpf/hashtab.c:237 [inline]
 __htab_lru_percpu_map_update_elem+0xd0/0xa30 kernel/bpf/hashtab.c:1166
 bpf_percpu_hash_update+0x5a/0x90 kernel/bpf/hashtab.c:1902
 bpf_map_update_value+0x1d8/0x320 kernel/bpf/syscall.c:172
 generic_map_update_batch+0x336/0x450 kernel/bpf/syscall.c:1342
 bpf_map_do_batch+0x286/0x2f0 kernel/bpf/syscall.c:3870
 __do_sys_bpf+0xb2a/0x9a60 kernel/bpf/syscall.c:4242
 __se_sys_bpf kernel/bpf/syscall.c:4136 [inline]
 __x64_sys_bpf+0x3d/0x50 kernel/bpf/syscall.c:4136
 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: 1 PID: 15645 Comm: syz-executor.5 Not tainted 5.9.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================