linux-kernel - RE: [PATCH 5/5] tty: n_gsm: Fixed NULL ptr OOPs in tty_write

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Mon, 6 Jun 2011 17:13:41 +0000
From:	"Gorby, Russ" <russ.gorby@...el.com>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
CC:	Greg Kroah-Hartman <gregkh@...e.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Ahmed, Suhail" <suhail.ahmed@...el.com>
Subject: RE: [PATCH 5/5] tty: n_gsm: Fixed NULL ptr OOPs in tty_write_room()



>-----Original Message-----
>From: Alan Cox [mailto:alan@...rguk.ukuu.org.uk]
>Sent: Friday, June 03, 2011 3:10 PM
>To: Gorby, Russ
>Cc: Greg Kroah-Hartman; linux-kernel@...r.kernel.org; Ahmed, Suhail
>Subject: Re: [PATCH 5/5] tty: n_gsm: Fixed NULL ptr OOPs in
>tty_write_room()
>
>On Fri,  3 Jun 2011 12:03:41 -0700
>Russ Gorby <russ.gorby@...el.com> wrote:
>
>> We saw a case where gsmld_output was called after the MUX
>> was shutdown. In this case gsm->tty was null so tty_write_room(NULL)
>> was called which resulted in an exception.
>
>This is papering over a problem. It shouldn't be happening. Do you have
>a
>copy of the backtrace of the event and does it occur a lot. If it's a
>one
>off freak event so far then instead add
>
>	if (gsm->tty == NULL) {
>		WARN_ON(1);
>		return -ENXIO;
>	}
>
>so we get dumps from it and the box survives when it occurs. That'll get
>us traces to nail it properly. For one your patch is not a valid
>ultimate fix because if it can occur what stops gsm->tty changing as it
>occurs.

[Gorby, Russ] Fair enough - no I don't have a trace and it only happened once. We're also running on the .36 kernel that I've seen some other TTY-weirdness with. I'll add the WARN_ON locally and try to capture another trace for analysis.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/