From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f70.google.com (mail-ot1-f70.google.com [209.85.210.70]) (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 DFB9935FF7D for ; Sun, 8 Feb 2026 15:17:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770563875; cv=none; b=FdsvW7F2xQc+jkfoz2V+2K4DnRTnfUUb4lcvJJC2TfnEH6jbFI6pGAS2hivVJceS7+P1XYhLnyV+Fb8uev/OX2zpTtnmFuApZXRtA/aGGoP4gayUfQLIRn/Plr2IJoX8Y7+waey1P0s0bX1poL/hWQkwbGZr/0Y7ZVIuBRBHZXo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770563875; c=relaxed/simple; bh=2j9pSVQEb68QpfSMu/erABwemGlfb6AK/eV0LH1RM+Y=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To:Cc: Content-Type; b=BGMz36lTS9A9RTo8WvHMmSYSO1onJxaXpAfKdSJzugMurpNMgoNIlpSkJDtPPApFB91Cam1rdSRCasdwah3FiZGKEhFVpr5FDJEbwPPNprfUB/UD1cnbqLkHUZ3Tst31RWD6YrbpjRithzkR8YNXZ/f6uHPdbf7jGXRnwU7iRD8= 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=209.85.210.70 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-f70.google.com with SMTP id 46e09a7af769-7d185984792so15721129a34.1 for ; Sun, 08 Feb 2026 07:17:54 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770563874; x=1771168674; h=cc:to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Eyjq+gG7AnfkbB+smMYKUKKsvHTyUByluhuE9HZ/PCA=; b=B/DcXJ69/NvFbmuaJR/q7RGsrWDdnZ9Mw0MdMKxbfspJKWjvtsC2wsqqNsP1TUq3ss XMiCabYoKLTr+QwkbTpi+fi7HCyFjj3vgWtuLSyPLPchg9Lg6rdRPxfOzd+bMYIniIuy P7y6HVihUNj8Vp7UPSu1BFP7VebU5pJDQ96i/cWMu4Vx+CHBs7+ecJKrkQEDPoHmBNdR 0XECJmuIwtAkuc2KZb5frPGr0piPd3s3gT0QZt3eD26c6l10vSnKL7iifYfyc3Jllpvx i+TfXNV45Si8gYy31dwmmaO/6XmZ/9BMQ2K/saQRTO93wl/JGf1mI5BHSOs2lvNncg1Y yW4A== X-Forwarded-Encrypted: i=1; AJvYcCX/eE400wk7JpVyPwNECDp1WAiEgQbKBn2qM20HYqw5EfA5sPZPZi71cS2o1nuqdK4gExW4k7xeDyfsOnU=@vger.kernel.org X-Gm-Message-State: AOJu0YysXH1FIOwxYUz9/ppWyFdF6wHNVjSgES1l4wyK9JCHIU6zmu28 bgogWIEVpPaPwfD8NR9XbCj4evJi35l+OmwyX8/G6D9q8JZCCNYR7Yx84yPReJoqW77cfaabWQ5 0UxGidLI2bgLa56qFEIQlX035nqL0jhd3KaLGGuV8GV3cN5hjrD/iWiHttJA= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:198a:b0:663:cb2:d67d with SMTP id 006d021491bc7-66d0a9583d4mr3633168eaf.37.1770563873872; Sun, 08 Feb 2026 07:17:53 -0800 (PST) Date: Sun, 08 Feb 2026 07:17:53 -0800 In-Reply-To: <6c618000-fe74-4429-9e91-b8a012598bef@rowland.harvard.edu> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6988a921.050a0220.1ad825.0001.GAE@google.com> Subject: Re: [syzbot] [usb?] INFO: task hung in usb_bulk_msg (2) From: syzbot To: stern@rowland.harvard.edu Cc: greearb@candelatech.com, hdanton@sina.com, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, michal.pecio@gmail.com, oneukum@suse.com, stern@rowland.harvard.edu, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" > On Sun, Feb 08, 2026 at 07:03:03AM -0800, syzbot wrote: >> Hello, >> >> syzbot has tested the proposed patch but the reproducer is still triggering an issue: >> INFO: task hung in usb_bulk_msg > > Okay, most likely the reason for the hang is that the count is 0. But > that doesn't explain everything. Let's get more info. > > Alan Stern > > #syz test: #https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git da87d45b1951 "#https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git" does not look like a valid git repo address. > > --- > drivers/usb/class/usbtmc.c | 7 +++---- > drivers/usb/gadget/udc/dummy_hcd.c | 11 +++++++++-- > 2 files changed, 12 insertions(+), 6 deletions(-) > > Index: usb-devel/drivers/usb/class/usbtmc.c > =================================================================== > --- usb-devel.orig/drivers/usb/class/usbtmc.c > +++ usb-devel/drivers/usb/class/usbtmc.c > @@ -1362,7 +1362,6 @@ static int send_request_dev_dep_msg_in(s > data->bTag++; > > kfree(buffer); > - if (retval < 0) > dev_err(&data->intf->dev, "%s returned %d\n", > __func__, retval); > > @@ -1404,7 +1403,7 @@ static ssize_t usbtmc_read(struct file * > if (count > INT_MAX) > count = INT_MAX; > > - dev_dbg(dev, "%s(count:%zu)\n", __func__, count); > + dev_info(dev, "%s(count:%zu)\n", __func__, count); > > retval = send_request_dev_dep_msg_in(file_data, count); > > @@ -1425,7 +1424,7 @@ static ssize_t usbtmc_read(struct file * > buffer, bufsize, &actual, > file_data->timeout); > > - dev_dbg(dev, "%s: bulk_msg retval(%u), actual(%d)\n", > + dev_info(dev, "%s: bulk_msg retval(%u), actual(%d)\n", > __func__, retval, actual); > > /* Store bTag (in case we need to abort) */ > @@ -1470,7 +1469,7 @@ static ssize_t usbtmc_read(struct file * > > file_data->bmTransferAttributes = buffer[8]; > > - dev_dbg(dev, "Bulk-IN header: N_characters(%u), bTransAttr(%u)\n", > + dev_info(dev, "Bulk-IN header: N_characters(%u), bTransAttr(%u)\n", > n_characters, buffer[8]); > > if (n_characters > remaining) { > Index: usb-devel/drivers/usb/gadget/udc/dummy_hcd.c > =================================================================== > --- usb-devel.orig/drivers/usb/gadget/udc/dummy_hcd.c > +++ usb-devel/drivers/usb/gadget/udc/dummy_hcd.c > @@ -762,8 +762,13 @@ static int dummy_dequeue(struct usb_ep * > ep = usb_ep_to_dummy_ep(_ep); > dum = ep_to_dummy(ep); > > - if (!dum->driver) > + if (!dum->driver) { > + dev_info(udc_dev(dum), "Got dequeue, no driver\n"); > return -ESHUTDOWN; > + } > + dev_info(udc_dev(dum), > + "dequeuing req %p from %s, len %d buf %p\n", > + req, _ep->name, _req->length, _req->buf); > > spin_lock_irqsave(&dum->lock, flags); > list_for_each_entry(iter, &ep->queue, queue) { > @@ -777,12 +782,14 @@ static int dummy_dequeue(struct usb_ep * > } > > if (retval == 0) { > - dev_dbg(udc_dev(dum), > + dev_info(udc_dev(dum), > "dequeued req %p from %s, len %d buf %p\n", > req, _ep->name, _req->length, _req->buf); > spin_unlock(&dum->lock); > usb_gadget_giveback_request(_ep, _req); > spin_lock(&dum->lock); > + } else { > + dev_info(udc_dev(dum), "request not found\n"); > } > spin_unlock_irqrestore(&dum->lock, flags); > return retval;