[PATCH] lightnvm: prevent memory leak in nvm_bb_chunk_sense

[PATCH] lightnvm: prevent memory leak in nvm_bb_chunk_sense

[Navid Emamdoost]

In nvm_bb_chunk_sense alloc_page allocates memory which is released at
the end of the function. But if nvm_submit_io_sync_raw fails the error
check skips the release and leaks the allocated page. To fix this issue
I moved the __free_page call before error check.

Fixes: aff3fb18f957 ("lightnvm: move bad block and chunk state logic to core")
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
---
 drivers/lightnvm/core.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 7543e395a2c6..5fdae518f6c9 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -849,11 +849,12 @@ static int nvm_bb_chunk_sense(struct nvm_dev *dev, struct ppa_addr ppa)
 	rqd.ppa_addr = generic_to_dev_addr(dev, ppa);
 
 	ret = nvm_submit_io_sync_raw(dev, &rqd);
-	if (ret)
-		return ret;
 
 	__free_page(page);
 
+	if (ret)
+		return ret;
+
 	return rqd.error;
 }
 
-- 
2.17.1

Re: [PATCH] lightnvm: prevent memory leak in nvm_bb_chunk_sense

[Markus Elfring]

> To fix this issue I moved the __free_page call before error check.

Would the wording “Move the __free_page() call before the error check.”
be more succinct for the change description?

Can the following code variant be applied at the end of this function?

 	return ret ? ret : rqd.error;

Regards,
Markus

Re: [PATCH] lightnvm: prevent memory leak in nvm_bb_chunk_sense

[Javier González]

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> On 30 Sep 2019, at 04.34, Navid Emamdoost <navid.emamdoost@gmail.com> wrote:
> 
> In nvm_bb_chunk_sense alloc_page allocates memory which is released at
> the end of the function. But if nvm_submit_io_sync_raw fails the error
> check skips the release and leaks the allocated page. To fix this issue
> I moved the __free_page call before error check.
> 
> Fixes: aff3fb18f957 ("lightnvm: move bad block and chunk state logic to core")
> Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
> ---
> drivers/lightnvm/core.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index 7543e395a2c6..5fdae518f6c9 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -849,11 +849,12 @@ static int nvm_bb_chunk_sense(struct nvm_dev *dev, struct ppa_addr ppa)
> 	rqd.ppa_addr = generic_to_dev_addr(dev, ppa);
> 
> 	ret = nvm_submit_io_sync_raw(dev, &rqd);
> -	if (ret)
> -		return ret;
> 
> 	__free_page(page);
> 
> +	if (ret)
> +		return ret;
> +
> 	return rqd.error;
> }
> 
> --
> 2.17.1

You’re right, there is a leak here. Fix looks good to me.

Reviewed-by: Javier González <javier@javigon.com>


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