lkml.org 
[lkml]   [2011]   [May]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] staging: altera-stapl: Fix memory leak of altera_init()
On Tue, 31 May 2011, Peter Hüwe wrote:

> Am Montag 30 Mai 2011, 22:45:04 schrieb Andre Bartke:
> > In case kzalloc() fails the second or third time
> > we should free the previous allocated resources.
>
> Good catch!
> Personally I prefer putting the cleanup logic to the bottom, maybe like this - but that's just personal preference.
>

Another alternative would be something like this:

key = kzalloc(33 * sizeof(char), GFP_KERNEL);
value = kzalloc(257 * sizeof(char), GFP_KERNEL);
astate = kzalloc(sizeof(struct altera_state), GFP_KERNEL);
if (!astate || !value || ! key) {
kfree(astate);
kfree(value);
kfree(key);
return -ENOMEM;
}
Ohh and btw, in your suggestion (below), why don't you initialize 'retval'
to -ENOMEM and then set it to zero once after all the allocations have
completed? That would remove the need to set it to -ENOMEM 3 times before
the goto's... Sure, you are seting it 3 times in error paths and my
suggestion would introduce a retval=0; in the normal path, but the code
would be shorter and more readable IMHO.

/Jesper Juhl


> >From 1a13a1d7a2bad26f050ecc342741b6c07cac2b8a Mon Sep 17 00:00:00 2001
> From: Peter Huewe <peterhuewe@gmx.de>
> Date: Tue, 31 May 2011 00:54:27 +0200
> Subject: [PATCH] staging: altera-stapl: Fix memory leak of altera_init()
>
> In case kzalloc() fails the second or third time
> we should free the previous allocated resources.
> In order to keep one return point and to keep the cleanup code to one
> place, some reordering was necessary.
>
> Also while at it, removed the *sizeof(char) - to quote Linus:
> "" Also removed the silly "* sizeof(u8)". If that isn't 1, we have way
> deeper problems than a simple multiplication can fix. """
>
> Reported-by: Andre Bartke <andre.bartke@gmail.com>
> Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
> ---
> drivers/staging/altera-stapl/altera.c | 33 +++++++++++++++++++++------------
> 1 files changed, 21 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/staging/altera-stapl/altera.c b/drivers/staging/altera-stapl/altera.c
> index 05aad35..09392ce 100644
> --- a/drivers/staging/altera-stapl/altera.c
> +++ b/drivers/staging/altera-stapl/altera.c
> @@ -2430,16 +2430,23 @@ int altera_init(struct altera_config *config, const struct firmware *fw)
> int index = 0;
> s32 offset = 0L;
> s32 error_address = 0L;
> + int retval = 0;
>
> - key = kzalloc(33 * sizeof(char), GFP_KERNEL);
> - if (!key)
> - return -ENOMEM;
> - value = kzalloc(257 * sizeof(char), GFP_KERNEL);
> - if (!value)
> - return -ENOMEM;
> + key = kzalloc(33, GFP_KERNEL);
> + if (!key) {
> + retval = -ENOMEM;
> + goto out;
> + }
> + value = kzalloc(257, GFP_KERNEL);
> + if (!value) {
> + retval = -ENOMEM;
> + goto free_key;
> + }
> astate = kzalloc(sizeof(struct altera_state), GFP_KERNEL);
> - if (!astate)
> - return -ENOMEM;
> + if (!astate) {
> + retval = -ENOMEM;
> + goto free_value;
> + }
>
> astate->config = config;
> if (!astate->config->jtag_io) {
> @@ -2518,10 +2525,12 @@ int altera_init(struct altera_config *config, const struct firmware *fw)
> } else if (exec_result)
> printk(KERN_ERR "%s: error %d\n", __func__, exec_result);
>
> - kfree(key);
> - kfree(value);
> kfree(astate);
> -
> - return 0;
> +free_value:
> + kfree(value);
> +free_key:
> + kfree(key);
> +out:
> + return retval;
> }
> EXPORT_SYMBOL(altera_init);
>

--
Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/
Don't top-post http://www.catb.org/jargon/html/T/top-post.html
Plain text mails only, please.
\
 
 \ /
  Last update: 2011-05-31 01:23    [from the cache]
©2003-2011 Jasper Spaans