Martin, Please take a look at the trace below. I think we just need to annotate bpf_lru_node_set_ref() with data_race(). wdyt? Too bad there is no reproducer. On Tue, Apr 25, 2023 at 12:31 AM syzbot <syzbot+ebe648a84e8784763f82@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 6a66fdd29ea1 Merge tag 'rust-fixes-6.3' of https://github... > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=160d8948280000 > kernel config: https://syzkaller.appspot.com/x/.config?x=fa4baf7c6b35b5d5 > dashboard link: https://syzkaller.appspot.com/bug?extid=ebe648a84e8784763f82 > compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/78937867b23a/disk-6a66fdd2.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/dfd6c176adff/vmlinux-6a66fdd2.xz > kernel image: https://storage.googleapis.com/syzbot-assets/51509bf47166/bzImage-6a66fdd2.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+ebe648a84e8784763f82@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KCSAN: data-race in __bpf_lru_list_rotate / __htab_lru_percpu_map_update_elem > > write to 0xffff888137038deb of 1 bytes by task 11240 on cpu 1: > __bpf_lru_node_move kernel/bpf/bpf_lru_list.c:113 [inline] > __bpf_lru_list_rotate_active kernel/bpf/bpf_lru_list.c:149 [inline] > __bpf_lru_list_rotate+0x1bf/0x750 kernel/bpf/bpf_lru_list.c:240 > 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+0x638/0xe20 kernel/bpf/bpf_lru_list.c:499 > prealloc_lru_pop kernel/bpf/hashtab.c:290 [inline] > __htab_lru_percpu_map_update_elem+0xe7/0x820 kernel/bpf/hashtab.c:1316 > bpf_percpu_hash_update+0x5e/0x90 kernel/bpf/hashtab.c:2313 > bpf_map_update_value+0x2a9/0x370 kernel/bpf/syscall.c:200 > generic_map_update_batch+0x3ae/0x4f0 kernel/bpf/syscall.c:1687 > bpf_map_do_batch+0x2d9/0x3d0 kernel/bpf/syscall.c:4534 > __sys_bpf+0x338/0x810 > __do_sys_bpf kernel/bpf/syscall.c:5096 [inline] > __se_sys_bpf kernel/bpf/syscall.c:5094 [inline] > __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5094 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > read to 0xffff888137038deb of 1 bytes by task 11241 on cpu 0: > bpf_lru_node_set_ref kernel/bpf/bpf_lru_list.h:70 [inline] > __htab_lru_percpu_map_update_elem+0x2f1/0x820 kernel/bpf/hashtab.c:1332 > bpf_percpu_hash_update+0x5e/0x90 kernel/bpf/hashtab.c:2313 > bpf_map_update_value+0x2a9/0x370 kernel/bpf/syscall.c:200 > generic_map_update_batch+0x3ae/0x4f0 kernel/bpf/syscall.c:1687 > bpf_map_do_batch+0x2d9/0x3d0 kernel/bpf/syscall.c:4534 > __sys_bpf+0x338/0x810 > __do_sys_bpf kernel/bpf/syscall.c:5096 [inline] > __se_sys_bpf kernel/bpf/syscall.c:5094 [inline] > __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5094 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > value changed: 0x01 -> 0x00 > > Reported by Kernel Concurrency Sanitizer on: > CPU: 0 PID: 11241 Comm: syz-executor.3 Not tainted 6.3.0-rc7-syzkaller-00136-g6a66fdd29ea1 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 > ================================================================== > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
