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SubjectRe: [patch] fix BUG: in fw_realloc_buffer
Jeff Moyer <jmoyer@redhat.com> wrote:
>
> Hi,
>
> The fw_realloc_buffer routine does not handle an increase in buffer size of
> more than 4k. It's not clear to me why it expects that it will only get an
> extra 4k of data. The attached patch modifies fw_realloc_buffer to vmalloc
> as much memory as is requested, instead of what we previously had + 4k.
>
> I've tested this on my laptop, which would crash occaisionally on boot
> without the patch. With the patch, it hasn't crashed, but I can't be
> certain that this code path is exercised.
>
> Comments are very welcome.
>
> Thanks,
>
> Jeff
>
> Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
>
> --- vanilla/drivers/base/firmware_class.c.orig 2006-02-13 15:46:15.000000000 -0500
> +++ vanilla/drivers/base/firmware_class.c 2006-02-13 15:46:04.000000000 -0500
> @@ -211,18 +211,22 @@ static int
> fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
> {
> u8 *new_data;
> + int new_size = fw_priv->alloc_size;
>
> if (min_size <= fw_priv->alloc_size)
> return 0;
>
> - new_data = vmalloc(fw_priv->alloc_size + PAGE_SIZE);
> + while (new_size < min_size)
> + new_size += PAGE_SIZE;
> +
> + new_data = vmalloc(new_size);
> if (!new_data) {
> printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
> /* Make sure that we don't keep incomplete data */
> fw_load_abort(fw_priv);
> return -ENOMEM;
> }
> - fw_priv->alloc_size += PAGE_SIZE;
> + fw_priv->alloc_size = new_size;
> if (fw_priv->fw->data) {
> memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
> vfree(fw_priv->fw->data);

A little bit neater this way, I think?

--- devel/drivers/base/firmware_class.c~firmware-fix-bug-in-fw_realloc_buffer 2006-02-13 14:45:52.000000000 -0800
+++ devel-akpm/drivers/base/firmware_class.c 2006-02-13 14:52:05.000000000 -0800
@@ -211,18 +211,20 @@ static int
fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
{
u8 *new_data;
+ int new_size = fw_priv->alloc_size;

if (min_size <= fw_priv->alloc_size)
return 0;

- new_data = vmalloc(fw_priv->alloc_size + PAGE_SIZE);
+ new_size = ALIGN(min_size, PAGE_SIZE);
+ new_data = vmalloc(new_size);
if (!new_data) {
printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
/* Make sure that we don't keep incomplete data */
fw_load_abort(fw_priv);
return -ENOMEM;
}
- fw_priv->alloc_size += PAGE_SIZE;
+ fw_priv->alloc_size = new_size;
if (fw_priv->fw->data) {
memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
vfree(fw_priv->fw->data);
_
-
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