From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f77.google.com (mail-ot1-f77.google.com [209.85.210.77]) (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 71DAE1EF09B for ; Mon, 6 Apr 2026 20:57:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775509058; cv=none; b=ciABQEcODmv8F4GMroKin4E9uwMZviqGg4KwfmhrLLYhu93gTyf7zR4Mz78zdHzakv6JEpTLVBHAsf8LnE6ZgUYH3yh2lLzMq3bVT5cjRX01VPcBUPRMJi8wwGHabaGnpAHQgQXg/cmaBMKTS0KLYltUOqQGIfF/IST+ca8ekyY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775509058; c=relaxed/simple; bh=FtsIl5QLObpJJOr79nVtYG8IMGGQMtKFTzb1IPtRcgw=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=F6stqKyQdsbcHz7Q40iFlHUYFnemAOZwTBul52WYJMNhhm1f1M0NtKF/H8Vr6EW54IMsM8ISG6sod4HIbvjrz7KbZGPw5a7GXOECN7JHMFaxQBpXgsr/bWDxc3p+C0sRre56Gt+y+bJmyi/OS4u/n5EJknYfgDklDCWPt/wyAnQ= 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=209.85.210.77 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-ot1-f77.google.com with SMTP id 46e09a7af769-7dbc38e0e64so4194389a34.0 for ; Mon, 06 Apr 2026 13:57:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775509056; x=1776113856; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=n5Ibwoiivy+FWnfB/EMTkKmS+iZgWA3oBT3SHFxz4rQ=; b=Yeqw+XNB6BayM1YLAPyKmESe4qH32+q5nuQr0A/VbCrdjty8OA3G74TeK9zAK15gJq Lp234Sn8pfHRINmlnFge0tfEbOalJ3CBQjLK/P85yZ06H7mD2gDOSptlGmGnCVTyQr3M YYScKW/GMroOJIRtUpmNUtSxZWAm8baKZO4Ik1xLg1KpbWp0mEWXtN02ErMatfQbu1wC +HFnGAQoCTUwLdngH8Lu4S5cjBq9jHXRpgaIqPt7xEPjWgn4rvonQf93rik2wPd8tR+a X9vREDQtMWj4zJWUTXe+/Ok/ge42tcn26b87B2ZElB6QAUZcDu5fmmdqnPL3B4nbBQ+M MElA== X-Gm-Message-State: AOJu0Yw5itwOjR52Z09V1gSw7qVxM8XsDpPZiZFbaq3uIU4VjYlGrkrX umcf3gYnZCY1Td87+QCXTXEXi524PRmpbqKS24GvdPDTvS6Pm9u8QDhfrdCUkef7Z4JOPZhrvc0 ZmAox3X6KJAPTSFtO6Czs1PM+9o74ExKqr+N7+4rHcX+gcd3erdIrJsDQVoDhTw== Precedence: bulk X-Mailing-List: linux-can@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:2d42:b0:680:17e0:4443 with SMTP id 006d021491bc7-68220a48ef3mr7225063eaf.63.1775509056444; Mon, 06 Apr 2026 13:57:36 -0700 (PDT) Date: Mon, 06 Apr 2026 13:57:36 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69d41e40.a70a0220.a26f2.0040.GAE@google.com> Subject: [syzbot] [can?] KCSAN: data-race in _copy_from_iter / bcm_can_tx 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: 7ca6d1cfec80 Merge tag 'powerpc-7.0-4' of git://git.kernel.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=13b359f6580000 kernel config: https://syzkaller.appspot.com/x/.config?x=3a78dd265deac3a9 dashboard link: https://syzkaller.appspot.com/bug?extid=71cffbc1f77596292d08 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/22943b1048bd/disk-7ca6d1cf.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/36afcbebeb04/vmlinux-7ca6d1cf.xz kernel image: https://storage.googleapis.com/syzbot-assets/3088e4f4695f/bzImage-7ca6d1cf.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+71cffbc1f77596292d08@syzkaller.appspotmail.com ================================================================== BUG: KCSAN: data-race in _copy_from_iter / bcm_can_tx read to 0xffff88810cf825f8 of 72 bytes by interrupt on cpu 1: skb_put_data include/linux/skbuff.h:2800 [inline] bcm_can_tx+0x1b3/0x4c0 net/can/bcm.c:327 bcm_tx_timeout_handler+0xe5/0x290 net/can/bcm.c:478 __run_hrtimer kernel/time/hrtimer.c:1785 [inline] __hrtimer_run_queues+0x218/0x4f0 kernel/time/hrtimer.c:1849 hrtimer_run_softirq+0xe0/0x2c0 kernel/time/hrtimer.c:1866 handle_softirqs+0xb9/0x2a0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x39/0xc0 kernel/softirq.c:723 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0x37/0x80 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 write to 0xffff88810cf825f8 of 72 bytes by task 5344 on cpu 0: instrument_copy_from_user_before include/linux/instrumented.h:147 [inline] copy_from_user_iter lib/iov_iter.c:66 [inline] iterate_iovec include/linux/iov_iter.h:52 [inline] iterate_and_advance2 include/linux/iov_iter.h:304 [inline] iterate_and_advance include/linux/iov_iter.h:330 [inline] __copy_from_iter lib/iov_iter.c:261 [inline] _copy_from_iter+0x258/0xea0 lib/iov_iter.c:272 copy_from_iter include/linux/uio.h:228 [inline] copy_from_iter_full include/linux/uio.h:245 [inline] memcpy_from_msg include/linux/skbuff.h:4273 [inline] bcm_tx_setup+0xae5/0xdd0 net/can/bcm.c:966 bcm_sendmsg+0x357/0x4a0 net/can/bcm.c:1434 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0x563/0x5b0 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+0x194c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:47 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 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 5344 Comm: syz.3.483 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 ================================================================== --- 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