From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f79.google.com (mail-oo1-f79.google.com [209.85.161.79]) (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 17C291A304A for ; Sun, 25 Jan 2026 08:35:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.79 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769330129; cv=none; b=Eb0gckWuyRnYgn/huoXj9sc0bD7ugxZ5lLCY7XWnqY6lEqt0VweNlipIv4wXmx8hO5BsQ4yW59LBZEvsSK+DJ1lGtuRcyTVXmS83b2um8kljDOZcPiXT70U7uChc9zpMPWzKqT1W7ZjUJo7XWXqcyjx7822qjPceBX/RVKmKcMk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769330129; c=relaxed/simple; bh=Az+is/AFn37WkDbsnSQSI08Mp9H1ubJiUScdlsH+kIE=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=anm6bPqxABGctPHhfc7fjG5La4MR9b93YphFplNi72rqrARYkS1BH/bWedPEeVDWFM9xbFkLErTHtWUcep3gcF4NT2+8GOHIHf6dyHVdCcuYsUtY3SuJOjFwAbsqysedmng8UCUTNXdLnOxr/WBKmZsSzTYbKjO1Tucv31S+jZs= 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=209.85.161.79 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-f79.google.com with SMTP id 006d021491bc7-66115eb3950so6770063eaf.3 for ; Sun, 25 Jan 2026 00:35:27 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769330127; x=1769934927; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=HJVimj3LwoMN/4DXPtWP7/sOCmqjKaZSVowjkdE5ukU=; b=dM0yabJBU1hZAQ209BmHrV/OtcAF1tu+LwHW5QFziNOPheD8VhMAcVlmzehIhyW2b1 skQfSesd3yXrg8wDweI0vm3LaWgKckt5toxqK8fDe1+SVcZuK9Wf6Gx3SvWQIphVBlrC /EkJ+mcEZFjuOLyOnYwLAtNId4OV41xtQK1HZZVbNUZKF5R1LyVmpzCKIwSLgJxpNh/i CuHMkyiiLmfQksOqF2316shQf+ep6GeYz+sRRc1bRrm6QdWatJIVK1WIZGeBJTciaXkh GTAancZH99xbRBI8USm9M+L0kuahwgO7ix46CyDOX8dr3h+5UCUm8DprXESGVcBPZ8AM zmTg== X-Forwarded-Encrypted: i=1; AJvYcCUeBZNhIOc9KDeKtn5z8rI1va9SFwJ4DZSbQs4pHn+uEVBd2ZHR4zBqFEOEnZfSPD/3LFHBBCBhthVJaSQ=@vger.kernel.org X-Gm-Message-State: AOJu0YxAZIJqt+hvgDOArvgeYtf1J7rxqwX08gbFK17bxEa9duAhaTyM Qs8AVEVYfP5tbRNj8ZV+xbnBomjL94TUoOl7v04PvbCWwTQEsYB28OI1DHrNro4yJMhEhSR0U9v 4bA7zYCr4DlwZA8tYOT8vMCigQxwxd37A+IjeYzMQRwOjGvHcUZLMEod5z4k= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:c83:b0:662:c1a7:e165 with SMTP id 006d021491bc7-662e04022e4mr575732eaf.30.1769330127040; Sun, 25 Jan 2026 00:35:27 -0800 (PST) Date: Sun, 25 Jan 2026 00:35:27 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6975d5cf.a00a0220.33ccc7.0022.GAE@google.com> Subject: [syzbot] [can?] KCSAN: data-race in bcm_rx_setup / bcm_rx_update_and_send From: syzbot To: linux-can@vger.kernel.org, linux-kernel@vger.kernel.org, mkl@pengutronix.de, socketcan@hartkopp.net, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 24d479d26b25 Linux 6.19-rc6 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=153a9b9a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=676c6f0212d0c041 dashboard link: https://syzkaller.appspot.com/bug?extid=75e5e4ae00c3b4bb544e 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/e47d2b960e97/disk-24d479d2.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/75c59e1fc76a/vmlinux-24d479d2.xz kernel image: https://storage.googleapis.com/syzbot-assets/e42579adf478/bzImage-24d479d2.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+75e5e4ae00c3b4bb544e@syzkaller.appspotmail.com UDPLite6: UDP-Lite is deprecated and scheduled to be removed in 2025, please contact the netdev mailing list ================================================================== BUG: KCSAN: data-race in bcm_rx_setup / bcm_rx_update_and_send read to 0xffff88811adccc40 of 16 bytes by interrupt on cpu 1: bcm_rx_changed net/can/bcm.c:500 [inline] bcm_rx_update_and_send+0x37f/0x420 net/can/bcm.c:553 bcm_rx_handler+0x2b0/0x580 net/can/bcm.c:739 deliver net/can/af_can.c:575 [inline] can_rcv_filter+0x3c6/0x4f0 net/can/af_can.c:636 can_receive+0xfb/0x1c0 net/can/af_can.c:662 canfd_rcv+0xed/0x190 net/can/af_can.c:705 __netif_receive_skb_one_core net/core/dev.c:6152 [inline] __netif_receive_skb+0x120/0x270 net/core/dev.c:6265 process_backlog+0x228/0x420 net/core/dev.c:6617 __napi_poll+0x5f/0x300 net/core/dev.c:7681 napi_poll net/core/dev.c:7744 [inline] net_rx_action+0x452/0x930 net/core/dev.c:7896 handle_softirqs+0xb9/0x280 kernel/softirq.c:622 run_ksoftirqd+0x1c/0x30 kernel/softirq.c:1063 smpboot_thread_fn+0x32a/0x510 kernel/smpboot.c:160 kthread+0x488/0x510 kernel/kthread.c:463 ret_from_fork+0x148/0x280 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 write to 0xffff88811adccc40 of 16 bytes by task 3847 on cpu 0: bcm_rx_setup+0x7c5/0xe00 net/can/bcm.c:1259 bcm_sendmsg+0x1bb/0x4a0 net/can/bcm.c:1427 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x145/0x170 net/socket.c:742 ____sys_sendmsg+0x31e/0x4a0 net/socket.c:2592 ___sys_sendmsg+0x195/0x1e0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2681 x64_sys_call+0x17ba/0x3000 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 3847 Comm: syz.0.79 Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 ================================================================== --- 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