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KCSAN: data-race in __bpf_lru_node_move / bpf_lru_push_free

Status: closed as invalid on 2020/06/18 14:24
Subsystems: bpf
[Documentation on labels]
First crash: 1442d, last: 1442d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __bpf_lru_node_move / bpf_lru_push_free

write to 0xffff888121ede222 of 1 bytes by task 27152 on cpu 1:
 __bpf_lru_node_move+0xca/0x2d0 kernel/bpf/bpf_lru_list.c:111
 __bpf_lru_list_rotate_active.isra.0+0xef/0x110 kernel/bpf/bpf_lru_list.c:151
 __bpf_lru_list_rotate kernel/bpf/bpf_lru_list.c:240 [inline]
 bpf_lru_list_pop_free_to_local kernel/bpf/bpf_lru_list.c:329 [inline]
 bpf_common_lru_pop_free kernel/bpf/bpf_lru_list.c:447 [inline]
 bpf_lru_pop_free+0x9fe/0xa30 kernel/bpf/bpf_lru_list.c:499
 prealloc_lru_pop+0x30/0x70 kernel/bpf/hashtab.c:237
 htab_lru_map_update_elem+0x352/0x680 kernel/bpf/hashtab.c:1043
 bpf_map_update_value.isra.0+0x3bc/0x420 kernel/bpf/syscall.c:203
 generic_map_update_batch+0x273/0x3c0 kernel/bpf/syscall.c:1326
 bpf_map_do_batch+0x194/0x3a0 kernel/bpf/syscall.c:3556
 __do_sys_bpf+0x1cca/0x3100 kernel/bpf/syscall.c:3767
 __se_sys_bpf kernel/bpf/syscall.c:3661 [inline]
 __x64_sys_bpf+0x47/0x60 kernel/bpf/syscall.c:3661
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888121ede222 of 1 bytes by task 27141 on cpu 0:
 bpf_common_lru_push_free kernel/bpf/bpf_lru_list.c:507 [inline]
 bpf_lru_push_free+0xf6/0x330 kernel/bpf/bpf_lru_list.c:555
 htab_lru_map_update_elem+0x544/0x680 kernel/bpf/hashtab.c:1072
 bpf_map_update_value.isra.0+0x3bc/0x420 kernel/bpf/syscall.c:203
 generic_map_update_batch+0x273/0x3c0 kernel/bpf/syscall.c:1326
 bpf_map_do_batch+0x194/0x3a0 kernel/bpf/syscall.c:3556
 __do_sys_bpf+0x1cca/0x3100 kernel/bpf/syscall.c:3767
 __se_sys_bpf kernel/bpf/syscall.c:3661 [inline]
 __x64_sys_bpf+0x47/0x60 kernel/bpf/syscall.c:3661
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 27141 Comm: syz-executor.4 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/05/13 07:54 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 a44eb8f7 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.