From: Oliver Neukum <oneukum@suse.com>
To: Alan Stern <stern@rowland.harvard.edu>,
syzbot <syzbot+9ca7a12fd736d93e0232@syzkaller.appspotmail.com>
Cc: 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: Thu, 28 Nov 2019 11:51:00 +0100 [thread overview]
Message-ID: <1574938260.21204.5.camel@suse.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1911271304410.1319-100000@iolanthe.rowland.org>
Am Mittwoch, den 27.11.2019, 13:07 -0500 schrieb Alan Stern:
> Index: usb-devel/drivers/media/radio/si470x/radio-si470x-usb.c
> ===================================================================
> --- usb-devel.orig/drivers/media/radio/si470x/radio-si470x-usb.c
> +++ usb-devel/drivers/media/radio/si470x/radio-si470x-usb.c
> @@ -370,15 +370,14 @@ static void si470x_int_in_callback(struc
> unsigned char tmpbuf[3];
>
> if (urb->status) {
> - if (urb->status == -ENOENT ||
> + if (!(urb->status == -ENOENT ||
> urb->status == -ECONNRESET ||
> - urb->status == -ESHUTDOWN) {
> - return;
> - } else {
> + urb->status == -ESHUTDOWN))
> dev_warn(&radio->intf->dev,
> - "non-zero urb status (%d)\n", urb->status);
> - goto resubmit; /* Maybe we can recover. */
> - }
> + "unrecognized urb status (%d)\n",
> + urb->status);
> + radio->int_in_running = 0;
> + return;
Hi,
it is a bit awkward to complain here, as your patch tests as correct
while mine didn't, but this is a race condition.
You can't guarantee that urb->status != 0.
The kill may happen while the completion handler is running for
a successful transfer.
I really appreciate your help, but I must understand what is going
wrong here. You are stopping the resubmit, but how could the resubmit
ever have not failed?
Regards
Oliver
next prev parent reply other threads:[~2019-11-28 10:51 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
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 [this message]
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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