On 26/8/25 10:23, Alexei Starovoitov wrote: > On Mon, Aug 25, 2025 at 7:20 PM Leon Hwang <hffilwlqm@xxxxxxxxx> wrote: >> >> >> >> On 26/8/25 01:39, syzbot wrote: >>> Hello, >>> >>> syzbot found the following issue on: >>> >>> HEAD commit: dd9de524183a xsk: Fix immature cq descriptor production >>> git tree: bpf >>> console output: https://syzkaller.appspot.com/x/log.txt?x=102da862580000 >>> kernel config: https://syzkaller.appspot.com/x/.config?x=c321f33e4545e2a1 >>> dashboard link: https://syzkaller.appspot.com/bug?extid=fa5c2814795b5adca240 >>> compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 >>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=142da862580000 >>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1588aef0580000 >>> >>> Downloadable assets: >>> disk image: https://storage.googleapis.com/syzbot-assets/5a3389c1558f/disk-dd9de524.raw.xz >>> vmlinux: https://storage.googleapis.com/syzbot-assets/c97133192a27/vmlinux-dd9de524.xz >>> kernel image: https://storage.googleapis.com/syzbot-assets/3ae5a1a88637/bzImage-dd9de524.xz >>> >>> IMPORTANT: if you fix the issue, please add the following tag to the commit: >>> Reported-by: syzbot+fa5c2814795b5adca240@xxxxxxxxxxxxxxxxxxxxxxxxx >>> >>> ============================================ >>> WARNING: possible recursive locking detected >>> syzkaller #0 Not tainted >>> -------------------------------------------- >>> syz-execprog/5866 is trying to acquire lock: >>> ffffc900048c10d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423 >>> >>> but task is already holding lock: >>> ffffc900048e90d8 (&rb->spinlock){-.-.}-{2:2}, at: __bpf_ringbuf_reserve+0x1c7/0x5a0 kernel/bpf/ringbuf.c:423 >>> >>> other info that might help us debug this: >>> Possible unsafe locking scenario: >>> >>> CPU0 >>> ---- >>> lock(&rb->spinlock); >>> lock(&rb->spinlock); >>> >>> *** DEADLOCK *** >>> >>> May be due to missing lock nesting notation >> >> Confirmed. >> >> I can reproduce this deadlock issue and will work on a fix. > > Don't. > > It's due to revert. > Once rqspinlock is fixed the revert will be reverted. OK. I'll test it after the fixing. Thanks, Leon
