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Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently
From: |
Anthony Liguori |
Subject: |
Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently |
Date: |
Fri, 29 May 2009 05:53:38 -0500 |
User-agent: |
Thunderbird 2.0.0.21 (X11/20090409) |
malc wrote:
> On Fri, 29 May 2009, Anthony Liguori wrote:
>
>
> Dereference of NULL is UB[1] and dereferencing result of malloc(1) will
> just plain work.
>
So let's ignoring returning NULL as a possibility..
>> 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).'
>
But the zero allocation isn't a bug if we return malloc(1). This is a
common convention and while it may not be portable to every platform's
underlying malloc, we can make this convention portable with qemu_malloc().
At the end of the day, the result is a harder to misuse qemu_malloc()
and that's a very good thing. I don't want a user to "discover" a
non-portable use of malloc() while trying to do something important.
Regards,
Anthony Liguori
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, (continued)
- 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, 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, Kevin Wolf, 2009/05/29
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently,
Anthony Liguori <=
- 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
- Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently, Glauber Costa, 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, Julian Seward, 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, David Turner, 2009/05/29