linux-kernel - Re: [PATCH] tty: hold lock across tty buffer finding and buffer filling

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

Message-ID: <20120315154018.1a4874eb@pyramind.ukuu.org.uk>
Date:	Thu, 15 Mar 2012 15:40:18 +0000
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	"Du, Alek" <alek.du@...el.com>
Cc:	"Tu, Xiaobing" <xiaobing.tu@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
	"Zhang, Yanmin" <yanmin.zhang@...el.com>,
	"Zuo, Jiao" <jiao.zuo@...el.com>
Subject: Re: [PATCH] tty: hold lock across tty buffer finding and buffer
 filling

On Thu, 15 Mar 2012 10:14:07 +0000
"Du, Alek" <alek.du@...el.com> wrote:

> Alan,
> 
> I agree with you for the case of multiple writers to the tty buffer.
> 
> But there is another case that cause kernel hang: driver is writing data to tty, while app shutdown the port or flush through IOCTL. The buf.tail is set to NULL, here is the log:
> 
> 
> <1>[ 4713.451954] BUG: unable to handle kernel NULL pointer dereference at
> 00000004
> <1>[ 4713.452424] IP: [<c14ff59c>] tty_insert_flip_string_fixed_flag+0x4c/0x90


Ouch.. yes that makes sense.

Alan
--
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/