From: Oliver Neukum <oneukum@suse.de>
To: Alan Stern <stern@rowland.harvard.edu>, eli.billauer@gmail.com
Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
hdegoede@redhat.com
Subject: Re: [PATCH v2] usb: core: Solve race condition in anchor cleanup functions
Date: Thu, 30 Jul 2020 09:28:25 +0200 [thread overview]
Message-ID: <1596094105.2508.1.camel@suse.de> (raw)
In-Reply-To: <20200729133846.GA1530967@rowland.harvard.edu>
Am Mittwoch, den 29.07.2020, 09:38 -0400 schrieb Alan Stern:
> > - spin_lock_irq(&anchor->lock);
> > - while (!list_empty(&anchor->urb_list)) {
> > - victim = list_entry(anchor->urb_list.prev, struct urb,
> > - anchor_list);
> > - /* we must make sure the URB isn't freed before we kill it*/
> > - usb_get_urb(victim);
> > - spin_unlock_irq(&anchor->lock);
> > - /* this will unanchor the URB */
> > - usb_kill_urb(victim);
> > - usb_put_urb(victim);
> > + do {
> > spin_lock_irq(&anchor->lock);
>
> All you have to do is move this spin_lock_irq() above the start of the
> outer loop...
usb_kill_urb() is unfortunately an operation that can sleep.
Regards
Oliver
prev parent reply other threads:[~2020-07-30 7:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-29 10:31 [PATCH v2] usb: core: Solve race condition in anchor cleanup functions eli.billauer
2020-07-29 13:38 ` Alan Stern
2020-07-29 15:08 ` Eli Billauer
2020-07-30 7:28 ` Oliver Neukum [this message]
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