On Sun, Mar 08, 2015 at 05:54:07PM +0100, Matteo Semenzato wrote:
> From: Matteo Semenzato <mattew8...@gmail.com>
> 
> Return -ENOMEM if allocating brd->flipbuf fails.
> 
> Signed-off-by: Matteo Semenzato <mattew8...@gmail.com>
> ---
>  drivers/staging/dgnc/dgnc_driver.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/staging/dgnc/dgnc_driver.c 
> b/drivers/staging/dgnc/dgnc_driver.c
> index f177d3a..711af02 100644
> --- a/drivers/staging/dgnc/dgnc_driver.c
> +++ b/drivers/staging/dgnc/dgnc_driver.c
> @@ -622,6 +622,10 @@ static int dgnc_found_board(struct pci_dev *pdev, int id)
>        * context, and there are no locks held.
>        */
>       brd->flipbuf = kzalloc(MYFLIPLEN, GFP_KERNEL);
> +     if (!brd->flipbuf) {
> +             kfree(brd);
> +             return -ENOMEM;

This leaves a freed pointer in "dgnc_Board[dgnc_NumBoards]" which is
sort of ugly.  It doesn't free "brd->msgbuf_head" which is a bug.

Please read my essay on error hanling:
https://plus.google.com/106378716002406849458

What we want is :

        ret = do_one();
        if (ret)
                return ret;
        ret = do_two();
        if (ret)
                goto undo_one;

        ret = do_three();
        if (ret)
                goto undo_two;

        return 0;

err_undo_two:
        undo_two();
err_undo_one:
        undo_one();

        return ret;

Basically, a list of commands and a mirror list of undos.  This is
standard kernel style and the error handling basically writes itself
automatically.

regards,
dan carpenter


> +     }
>  
>       wake_up_interruptible(&brd->state_wait);
>  
> -- 
> 2.3.1
> 
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