From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: "Du, Alek" <alek.du@intel.com>
Cc: "Tu, Xiaobing" <xiaobing.tu@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"Zhang, Yanmin" <yanmin.zhang@intel.com>,
"Zuo, Jiao" <jiao.zuo@intel.com>
Subject: Re: [PATCH] tty: hold lock across tty buffer finding and buffer filling
Date: Thu, 15 Mar 2012 15:40:18 +0000 [thread overview]
Message-ID: <20120315154018.1a4874eb@pyramind.ukuu.org.uk> (raw)
In-Reply-To: <09F19C497AD02E4EA4E14917772649B70FCD36C2@SHSMSX102.ccr.corp.intel.com>
On Thu, 15 Mar 2012 10:14:07 +0000
"Du, Alek" <alek.du@intel.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
next prev parent reply other threads:[~2012-03-15 15:38 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-15 2:06 Tu, Xiaobing
2012-03-15 10:08 ` Alan Cox
2012-03-15 10:14 ` Du, Alek
2012-03-15 15:40 ` Alan Cox [this message]
2012-03-16 9:43 ` Jiri Slaby
2012-03-16 9:49 ` Du, Alek
2012-03-16 9:57 ` Jiri Slaby
2012-03-16 10:01 ` Du, Alek
2012-03-16 10:04 ` Jiri Slaby
2012-03-16 10:08 ` Du, Alek
2012-03-16 10:22 ` Jiri Slaby
2012-03-16 11:33 ` Du, Alek
2012-03-16 12:03 ` Jiri Slaby
2012-03-16 13:50 ` Du, Alek
2012-03-16 20:53 ` Jiri Slaby
2012-03-17 1:05 ` Alek Du
2012-03-16 23:07 ` Alan Cox
2012-03-15 20:26 ` gregkh
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120315154018.1a4874eb@pyramind.ukuu.org.uk \
--to=alan@lxorguk.ukuu.org.uk \
--cc=alek.du@intel.com \
--cc=gregkh@linuxfoundation.org \
--cc=jiao.zuo@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=xiaobing.tu@intel.com \
--cc=yanmin.zhang@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome