From: Alan Stern <stern@rowland.harvard.edu>
To: Oliver Neukum <oneukum@suse.com>
Cc: syzbot <syzbot+9ca7a12fd736d93e0232@syzkaller.appspotmail.com>,
<andreyknvl@google.com>, <hverkuil@xs4all.nl>,
<linux-kernel@vger.kernel.org>, <linux-media@vger.kernel.org>,
<linux-usb@vger.kernel.org>, <mchehab@kernel.org>,
<syzkaller-bugs@googlegroups.com>
Subject: Re: KASAN: use-after-free Read in si470x_int_in_callback (2)
Date: Fri, 22 Nov 2019 15:12:55 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1911221506490.1511-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <1574449256.2659.2.camel@suse.com>
On Fri, 22 Nov 2019, Oliver Neukum wrote:
> Am Freitag, den 22.11.2019, 10:35 -0500 schrieb Alan Stern:
> > On Fri, 22 Nov 2019, syzbot wrote:
> >
> > > Hello,
> > >
> > > syzbot has tested the proposed patch but the reproducer still triggered
> > > crash:
> > > INFO: rcu detected stall in dummy_timer
> > >
> > > radio-si470x 1-1:0.0: non-zero urb status (-71)
> > > radio-si470x 4-1:0.0: non-zero urb status (-71)
> > > radio-si470x 3-1:0.0: non-zero urb status (-71)
> >
> > Oliver:
> >
> > The reason for this stall is because the driver goes into a tight
> > resubmit loop when the interrupt URB completes with an unrecognized
> > error status. Instead, the driver should log an error message and
> > avoid resubmitting. Error recovery can be done at a higher level.
> >
> > In other words, change the
> >
> > goto resubmit; /* Maybe we can recover. */
> >
> > line in the completion handler into a return.
(I guess you also should clear the int_in_running flag, although the
callback routine doesn't do that in the case of -ENOENT, -ECONNRESET,
or -ESHUTDOWN.)
>
> I thought so, too. That is why I poisoned the URB. Am I dense?
Poisoning the URB should work -- if you do it in the right place. The
probe routine might not be good enough; an unrecognized error can occur
after the probe has succeeded.
Did you modify si470x_int_in_callback()? That's where the tight loop
is.
Alan Stern
next prev parent reply other threads:[~2019-11-22 20:13 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-18 14:53 KASAN: use-after-free Read in si470x_int_in_callback (2) syzbot
2019-11-18 13:44 ` Oliver Neukum
2019-11-19 9:10 ` syzbot
2019-11-20 10:32 ` Oliver Neukum
2019-11-20 23:50 ` syzbot
2019-11-21 12:00 ` Oliver Neukum
2019-11-22 10:33 ` syzbot
2019-11-22 15:35 ` Alan Stern
2019-11-22 19:00 ` Oliver Neukum
2019-11-22 20:12 ` Alan Stern [this message]
2019-11-27 10:27 ` Oliver Neukum
2019-11-27 16:30 ` syzbot
2019-11-27 18:07 ` Alan Stern
2019-11-27 20:55 ` syzbot
2019-11-27 21:11 ` Alan Stern
2019-11-28 15:19 ` Oliver Neukum
2019-11-28 17:25 ` Alan Stern
2019-11-28 10:51 ` Oliver Neukum
2019-11-28 17:33 ` Alan Stern
2019-11-28 11:10 ` Oliver Neukum
2019-11-28 13:53 ` syzbot
2019-12-04 15:03 ` Oliver Neukum
2019-12-04 18:17 ` syzbot
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