From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f72.google.com (mail-oo1-f72.google.com [209.85.161.72]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2C85D36C584 for ; Thu, 12 Mar 2026 15:26:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.72 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773329194; cv=none; b=gOGALYw1pbYGzw6Yg8vKK2PENrdxTZA9z2y/rqrlJTbtKjwl0zfsksGwRxxu5chF6vz5GoDEf7rJ50fMc48NIM3BymYZVelsRc5rXB4qQ3IrnINiW9VMUodWg8YMFOhuXoXyuG6A0wifQtwvcVhRhnIaspl7cdiVS9i+FLgD+f8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773329194; c=relaxed/simple; bh=GHsK8YuZly8QH9uD0W7Wt/J9nBRPCip4pmNOoLPQ9Sw=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=A/Qsuiym5n/Xh7zCKLJt2At2PEEb3xYww5O4z7COfNKyesJMt/XRoxR4u05mTMowt0g4gzf1xh/otSoBQsdEalbxRS0KXItjpjrHVMHA6E+wKAqHrfQSlweX9+JWLunGK2snyM2ELUSJhmTwyWcGq7eqQmc2+ytTFy9a0/TCH+Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.72 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f72.google.com with SMTP id 006d021491bc7-66b612efb4aso14780666eaf.0 for ; Thu, 12 Mar 2026 08:26:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773329192; x=1773933992; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=Rj9s+mz7zHP4ESHMfr59tdOV8XXR/bIPPqhzBvT0ASY=; b=TLeCW40ROiTkjun0oup76Hz0k4sZDHTp44coDO1RAfOWdYPOgIm++OJ7H0uIVzLElk Bo+lEWRbDEtMOiZI4ZESHl6/ArKlxDDYBC4tOBNliy7/3jQSJeWXNMgXuNQoughntmxD r5CkwYzOs2Xnq/DB7nYliznbxBDrrFI9SQAse7oiuSg0ZR1hHDqTduKBpRWBuiQnL1zq t8n7PCJZu0y5+igU2SB+Q9r/87TfauDZm1qRx2jjOlrJQOwL7v8ZwPdcGYRgxlIvHtE0 ZB+CCXWmWXikcIKhmJjURLl1qEmGHpZAXNe7HZWUVxAWIUFbw/HQcJDbmSfw5brULzEY clLg== X-Forwarded-Encrypted: i=1; AJvYcCUMfx/bY98vLEEGUW6FQagfM20+apz6uDSuiBcYnZLAOu4JfpoLTrXM+bNrX8P424inawotgxM=@vger.kernel.org X-Gm-Message-State: AOJu0YxvRhyMHgpkw5v+suqD2yUDkHG9a3GCSwzpeluU9yUYIZ66FS3x iiBeamFZCQhyZKAOeJqHpxh4LvNdhd1UyGcaQg32dybkLsf3OzY042pcWMSpu34s9fySDvw7OcR kvCW9xh73Lq8qaMEa55LINiqxPkxVVo8mU5RftwqYTH1j2f8wf/6KY8D847U= Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:622:b0:67b:ba3d:56ba with SMTP id 006d021491bc7-67bd0792074mr3020473eaf.29.1773329192102; Thu, 12 Mar 2026 08:26:32 -0700 (PDT) Date: Thu, 12 Mar 2026 08:26:32 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69b2db28.a00a0220.94e15.0025.GAE@google.com> Subject: [syzbot] [net?] KCSAN: data-race in pfifo_fast_dequeue / pfifo_fast_enqueue (6) From: syzbot To: davem@davemloft.net, edumazet@google.com, horms@kernel.org, jhs@mojatatu.com, jiri@resnulli.us, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 37a93dd5c49b Merge tag 'net-next-7.0' of git://git.kernel... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1244fa52580000 kernel config: https://syzkaller.appspot.com/x/.config?x=ec543385a37b9f17 dashboard link: https://syzkaller.appspot.com/bug?extid=b44f2bbe286b9355c563 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/5c78f22cfb6c/disk-37a93dd5.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/77c2f419bced/vmlinux-37a93dd5.xz kernel image: https://storage.googleapis.com/syzbot-assets/5640d838c887/bzImage-37a93dd5.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+b44f2bbe286b9355c563@syzkaller.appspotmail.com ================================================================== BUG: KCSAN: data-race in pfifo_fast_dequeue / pfifo_fast_enqueue write to 0xffff88811d5ccc00 of 8 bytes by interrupt on cpu 0: __ptr_ring_zero_tail include/linux/ptr_ring.h:259 [inline] __ptr_ring_discard_one include/linux/ptr_ring.h:291 [inline] __ptr_ring_consume include/linux/ptr_ring.h:311 [inline] __skb_array_consume include/linux/skb_array.h:98 [inline] pfifo_fast_dequeue+0x770/0x8f0 net/sched/sch_generic.c:770 dequeue_skb net/sched/sch_generic.c:297 [inline] qdisc_restart net/sched/sch_generic.c:402 [inline] __qdisc_run+0x189/0xc80 net/sched/sch_generic.c:420 qdisc_run include/net/pkt_sched.h:120 [inline] net_tx_action+0x379/0x590 net/core/dev.c:5793 handle_softirqs+0xb9/0x280 kernel/softirq.c:622 do_softirq+0x45/0x60 kernel/softirq.c:523 __local_bh_enable_ip+0x70/0x80 kernel/softirq.c:450 local_bh_enable include/linux/bottom_half.h:33 [inline] bpf_test_run+0x2db/0x620 net/bpf/test_run.c:426 bpf_prog_test_run_skb+0x9a4/0xef0 net/bpf/test_run.c:1159 bpf_prog_test_run+0x204/0x340 kernel/bpf/syscall.c:4721 __sys_bpf+0x52e/0x7e0 kernel/bpf/syscall.c:6246 __do_sys_bpf kernel/bpf/syscall.c:6341 [inline] __se_sys_bpf kernel/bpf/syscall.c:6339 [inline] __x64_sys_bpf+0x41/0x50 kernel/bpf/syscall.c:6339 x64_sys_call+0x10cb/0x3020 arch/x86/include/generated/asm/syscalls_64.h:322 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff88811d5ccc00 of 8 bytes by task 22632 on cpu 1: __ptr_ring_produce include/linux/ptr_ring.h:106 [inline] ptr_ring_produce include/linux/ptr_ring.h:129 [inline] skb_array_produce include/linux/skb_array.h:44 [inline] pfifo_fast_enqueue+0xd5/0x2c0 net/sched/sch_generic.c:741 dev_qdisc_enqueue net/core/dev.c:4144 [inline] __dev_xmit_skb net/core/dev.c:4188 [inline] __dev_queue_xmit+0x6a4/0x1f20 net/core/dev.c:4795 dev_queue_xmit include/linux/netdevice.h:3384 [inline] __bpf_tx_skb net/core/filter.c:2153 [inline] __bpf_redirect_common net/core/filter.c:2197 [inline] __bpf_redirect+0x862/0x990 net/core/filter.c:2204 ____bpf_clone_redirect net/core/filter.c:2487 [inline] bpf_clone_redirect+0x20c/0x290 net/core/filter.c:2450 bpf_prog_53f18857bc887b09+0x22/0x2a bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] bpf_test_run+0x29d/0x620 net/bpf/test_run.c:423 bpf_prog_test_run_skb+0x9a4/0xef0 net/bpf/test_run.c:1159 bpf_prog_test_run+0x204/0x340 kernel/bpf/syscall.c:4721 __sys_bpf+0x52e/0x7e0 kernel/bpf/syscall.c:6246 __do_sys_bpf kernel/bpf/syscall.c:6341 [inline] __se_sys_bpf kernel/bpf/syscall.c:6339 [inline] __x64_sys_bpf+0x41/0x50 kernel/bpf/syscall.c:6339 x64_sys_call+0x10cb/0x3020 arch/x86/include/generated/asm/syscalls_64.h:322 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0xffff888104a93a00 -> 0x0000000000000000 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 22632 Comm: syz.0.4135 Tainted: G W syzkaller #0 PREEMPT(full) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 ================================================================== --- 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@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup