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Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently |
Date: |
Fri, 29 May 2009 12:34:45 +0200 |
User-agent: |
Thunderbird 2.0.0.21 (X11/20090320) |
malc schrieb:
> On Fri, 29 May 2009, Kevin Wolf wrote:
>
>> malc schrieb:
>>>> Putting the abort() in there is going to introduce a ton of subtle bugs,
>>>> I vote for changing qemu_malloc() to have a sane behavior.
>>> And those will be caught, given one a chance to analyze things, unlike
>>> head in the sand approach of hoping things would just work.
>>>
>>> After doing some research, after the aforementioned lengthy discussion,
>>> the only free OS that straight-forwardly described what it does was
>>> OpenBSD:
>>>
>>> http://www.openbsd.org/cgi-bin/man.cgi?query=malloc&apropos=0&sektion=0&manpath=OpenBSD+Current&arch=i386&format=html
>>>
>>> P.S. So far the abort that went into qemu_malloc caught one usage of zero
>>> allocation (once again coming from qcow2).
>> Zero allocation isn't a bug per se. Checking for NULL or dereferencing
>> is. Any value that can be freed, be it NULL or anything else, was
>> perfectly fine here without the abort() patch. So it actually was one of
>> the subtle bugs Anthony mentioned which are introduced by the abort().
>
> And once again, the code would have aborted on AIX with our without abort
> patch. The reason for abort is to identify and reason about all the call
> sites that do that.
Why would it have aborted? If AIX aborts on malloc(0), its malloc is
seriously broken. But as I have understood from previous discussion, AIX
just returns NULL. Would have been okay for this code.
Kevin
- [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, Jean-Christophe Dubois, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, Kevin Wolf, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, Anthony Liguori, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, malc, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, Kevin Wolf, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, malc, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently,
Kevin Wolf <=
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, malc, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, Kevin Wolf, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, Anthony Liguori, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, malc, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, Kevin Wolf, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, Anthony Liguori, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, malc, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, Gerd Hoffmann, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, Paul Brook, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, Gerd Hoffmann, 2009/05/29