syzbot

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BUG: KCSAN: data-race in __htab_lru_percpu_map_update_elem / bpf_lru_pop_free

write to 0xffff8880a7b9a563 of 1 bytes by task 19763 on cpu 0:
 __bpf_lru_node_move_in kernel/bpf/bpf_lru_list.c:92 [inline]
 __local_list_flush kernel/bpf/bpf_lru_list.c:298 [inline]
 bpf_lru_list_pop_free_to_local kernel/bpf/bpf_lru_list.c:327 [inline]
 bpf_common_lru_pop_free kernel/bpf/bpf_lru_list.c:447 [inline]
 bpf_lru_pop_free+0x322/0xeb0 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:1909
 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 0xffff8880a7b9a563 of 1 bytes by task 19753 on cpu 1:
 bpf_lru_node_set_ref kernel/bpf/bpf_lru_list.h:69 [inline]
 __htab_lru_percpu_map_update_elem+0x6b9/0xa30 kernel/bpf/hashtab.c:1180
 bpf_percpu_hash_update+0x5a/0x90 kernel/bpf/hashtab.c:1909
 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: 19753 Comm: syz-executor.1 Not tainted 5.9.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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