linux-kernel - Re: [PATCH] coredump: prevent double-free on an error path in core dumper

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Message-ID: <20120912190038.GA12473@redhat.com>
Date:	Wed, 12 Sep 2012 21:00:38 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Venu Byravarasu <vbyravarasu@...dia.com>
Cc:	Denys Vlasenko <vda.linux@...glemail.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Roland McGrath <roland@...k.frob.com>
Subject: Re: [PATCH] coredump: prevent double-free on an error path in core
	dumper

On 09/12, Oleg Nesterov wrote:
>
> On 09/12, Venu Byravarasu wrote:
> >
> > > --- a/fs/binfmt_elf.c
> > > +++ b/fs/binfmt_elf.c
> > > @@ -1695,30 +1695,19 @@ static int elf_note_info_init(struct elf_note_info
> > > *info)
> > >  		return 0;
> > >  	info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL);
> >
> > Why don't you change kmalloc to devm_kzalloc, so that free can be ignored altogether.
>
> kzalloc(), I guess...
>
> Still I can't understand what did you mean.

Denys explained me privately what did you mean.

Well. elf_core_dump() does a lot of kmalloc's. We should either
change them all or nothing. And even if we do this, I think this
particular patch makes sense anyway.

Not sure we want "struct device" for this, perhaps this devres
code should be generalized somehow.

Oleg.

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