linux-kernel - Re: lib/argv_split.c : should argv be kfree'ed ?

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Message-ID: <20140629153711.GA16902@mguzik.redhat.com>
Date:	Sun, 29 Jun 2014 17:37:12 +0200
From:	Mateusz Guzik <mguzik@...hat.com>
To:	Toralf Förster <toralf.foerster@....de>
Cc:	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: lib/argv_split.c : should argv be kfree'ed ?

On Sun, Jun 29, 2014 at 04:40:17PM +0200, Toralf Förster wrote:
> On 06/29/2014 12:04 AM, Mateusz Guzik wrote:
> > On Sat, Jun 28, 2014 at 11:52:37PM +0200, Toralf Förster wrote:
> >> /me wonders if this patch is needed here :
> >>
> >>
> >> diff --git a/lib/argv_split.c b/lib/argv_split.c
> >> index e927ed0..7de4cb4 100644
> >> --- a/lib/argv_split.c
> >> +++ b/lib/argv_split.c
> >> @@ -85,6 +85,7 @@ char **argv_split(gfp_t gfp, const char *str, int *argcp)
> >>                         *argv++ = argv_str;
> >>                 }
> >>         }
> >> +       kfree (argv);
> >>         *argv = NULL;
> >>
> >>         if (argcp)
> >>
> > 
> > No, see argv_free.
> > 
> Ah, understood, it is in the responsibility of the caller to avoid the memleak.
> BTW may I ask you about your opinion about this warning of cppcheck in lib/flex_array.c:
> 
>         for (part_nr = start_part; part_nr <= end_part; part_nr++) {<--- Memory leak: part
>                 part = __fa_get_part(fa, part_nr, flags);
>                 if (!part)
>                         return -ENOMEM;
>         }
>         return 0;
> 


static struct flex_array_part *
__fa_get_part(struct flex_array *fa, int part_nr, gfp_t flags)
{
        struct flex_array_part *part = fa->parts[part_nr];
        if (!part) {
                part = kmalloc(sizeof(struct flex_array_part), flags);
                if (!part)
                        return NULL;
                if (!(flags & __GFP_ZERO))
                        memset(part, FLEX_ARRAY_FREE,
                                sizeof(struct flex_array_part));
                fa->parts[part_nr] = part;

		^^^^^^^^^^^^^^^^^^^^^^^^^^
        }
        return part;
}


Allocated memory is not leaked. It is stored in 'fa' and is perfectly
reachable afterwards.

'part' in flex_array_prealloc is only used for error checking.

-- 
Mateusz Guzik
--
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