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

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Message-ID: <20120912130020.GA29585@redhat.com>
Date:	Wed, 12 Sep 2012 15:00:20 +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, 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. If kmalloc() fails we
return "fail" and ->psinfo = NULL, the subsequent kfree(NULL) is nop.

Oleg.

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