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Date:   Mon, 14 Oct 2019 11:13:18 -0400 (EDT)
From:   Alan Stern <stern@rowland.harvard.edu>
To:     Oliver Neukum <oneukum@suse.com>
cc:     Steven Rostedt <rostedt@goodmis.org>, Jens Axboe <axboe@kernel.dk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        <linux-block@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        <linux-usb@vger.kernel.org>
Subject: Re: Lockup on USB and block devices
In-Reply-To: <1571054381.19529.16.camel@suse.com>
Message-ID: <Pine.LNX.4.44L0.1910141112031.28937-100000@netrider.rowland.org>
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On Mon, 14 Oct 2019, Oliver Neukum wrote:

> Am Dienstag, den 01.10.2019, 14:31 -0400 schrieb Alan Stern:
> > It looks like a problem with your xHCI USB host controller.  Normally a
> > usb-storage transfer would be aborted after 90 seconds.  But if the
> > host controller (or its driver) isn't working right, and the abort
> > never completes, you end up with a situation like this -- usb-storage
> > and the higher SCSI and block layers waiting indefinitely for an event
> > that won't occur.
> 
> Hi,
> 
> that would imply that usb_unlink_urb() is malfunctioning
> without taking down the whole bus. Is that likely?

Mathias is a better person to ask than me.  But yes, as far as I know,
something like that can happen.

Alan Stern