From: "Andreas Färber" <afaerber@suse.de>
To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-trivial <qemu-trivial@nongnu.org>,
Tim Hardeck <thardeck@suse.de>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-trivial] [Qemu-devel] [PATCH 2/2] qemu queue: fix uninitialized removals
Date: Thu, 18 Oct 2012 15:24:25 +0200 [thread overview]
Message-ID: <50800309.5040706@suse.de> (raw)
In-Reply-To: <507FDD38.2010009@redhat.com>
Am 18.10.2012 12:43, schrieb Kevin Wolf:
> Am 17.10.2012 23:24, schrieb Tim Hardeck:
>> On Wednesday 17 October 2012 17:00:15 Andreas Färber wrote:
>>> Am 14.10.2012 15:08, schrieb Tim Hardeck:
>>>> When calling QTAILQ_REMOVE or QLIST_REMOVE on an unitialized list
>>>> QEMU segfaults.
>>>
>>> Can this be reproduced by a user today? Or is this just fixing the case
>>> that a developer forgot to initialize a list?
>> I am not sure but in this case it happened during an early VNC connection
>> state failure which most likely wouldn't happen to regular users.
>> I triggered it while working on the VNC connection part.
>>
>> The issue could most likely be also fixed in the VNC connection initialization
>> process but if this changes doesn't have a relevant performance impact they
>> might prevent some other/future crashes.
>
> At the same time, it could be hiding real bugs, where ignoring the
> QLIST_REMOVE() isn't the right fix. I can see your point, but I would be
> careful with making interfaces less strict.
What I don't get is, why is avoiding a NULL pointer dereference any
better from accessing random memory through an uninitialized pointer? Or
am I getting "uninitialized" wrong?
> In any case, I don't think this qualifies for qemu-trivial, Andreas.
Maybe not, but we don't have a clear maintainer that I'm aware of, and
no one else reviewed it for several days before I did. ;)
Andreas
--
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
WARNING: multiple messages have this Message-ID (diff)
From: "Andreas Färber" <afaerber@suse.de>
To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-trivial <qemu-trivial@nongnu.org>,
Tim Hardeck <thardeck@suse.de>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 2/2] qemu queue: fix uninitialized removals
Date: Thu, 18 Oct 2012 15:24:25 +0200 [thread overview]
Message-ID: <50800309.5040706@suse.de> (raw)
In-Reply-To: <507FDD38.2010009@redhat.com>
Am 18.10.2012 12:43, schrieb Kevin Wolf:
> Am 17.10.2012 23:24, schrieb Tim Hardeck:
>> On Wednesday 17 October 2012 17:00:15 Andreas Färber wrote:
>>> Am 14.10.2012 15:08, schrieb Tim Hardeck:
>>>> When calling QTAILQ_REMOVE or QLIST_REMOVE on an unitialized list
>>>> QEMU segfaults.
>>>
>>> Can this be reproduced by a user today? Or is this just fixing the case
>>> that a developer forgot to initialize a list?
>> I am not sure but in this case it happened during an early VNC connection
>> state failure which most likely wouldn't happen to regular users.
>> I triggered it while working on the VNC connection part.
>>
>> The issue could most likely be also fixed in the VNC connection initialization
>> process but if this changes doesn't have a relevant performance impact they
>> might prevent some other/future crashes.
>
> At the same time, it could be hiding real bugs, where ignoring the
> QLIST_REMOVE() isn't the right fix. I can see your point, but I would be
> careful with making interfaces less strict.
What I don't get is, why is avoiding a NULL pointer dereference any
better from accessing random memory through an uninitialized pointer? Or
am I getting "uninitialized" wrong?
> In any case, I don't think this qualifies for qemu-trivial, Andreas.
Maybe not, but we don't have a clear maintainer that I'm aware of, and
no one else reviewed it for several days before I did. ;)
Andreas
--
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
next prev parent reply other threads:[~2012-10-18 13:25 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-14 13:08 [Qemu-devel] [PATCH 0/2] fix segfaults triggered by failed vnc handshakes Tim Hardeck
2012-10-14 13:08 ` [Qemu-devel] [PATCH 1/2] vnc: fix segfault due to failed handshake Tim Hardeck
2012-10-17 12:52 ` [Qemu-trivial] " Andreas Färber
2012-10-17 12:52 ` Andreas Färber
2012-10-14 13:08 ` [Qemu-devel] [PATCH 2/2] qemu queue: fix uninitialized removals Tim Hardeck
2012-10-17 15:00 ` [Qemu-trivial] " Andreas Färber
2012-10-17 15:00 ` Andreas Färber
2012-10-17 21:24 ` [Qemu-trivial] " Tim Hardeck
2012-10-17 21:24 ` Tim Hardeck
2012-10-18 10:43 ` [Qemu-trivial] " Kevin Wolf
2012-10-18 10:43 ` Kevin Wolf
2012-10-18 13:24 ` Andreas Färber [this message]
2012-10-18 13:24 ` Andreas Färber
2012-10-18 13:32 ` [Qemu-trivial] " Peter Maydell
2012-10-18 13:32 ` Peter Maydell
2012-10-18 13:48 ` Peter Maydell
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=50800309.5040706@suse.de \
--to=afaerber@suse.de \
--cc=kwolf@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=qemu-trivial@nongnu.org \
--cc=thardeck@suse.de \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.