2016-10-30 19:53:28

by Christophe JAILLET

Subject: [PATCH] cxl: Fix memory allocation failure test

'cxl_context_alloc()' does not return an error pointer. It is just a
shortcut for a call to 'kzalloc' with 'sizeof(struct cxl_context)' as the
size parameter.

So its return value should be compared with NULL.
While fixing it, simplify a bit the code.

Signed-off-by: Christophe JAILLET <[email protected]>
---
un-compiled because I don't have the required cross build environment.
---
drivers/misc/cxl/api.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
index 2e5233b60971..2b88ad8a2a89 100644
--- a/drivers/misc/cxl/api.c
+++ b/drivers/misc/cxl/api.c
@@ -30,10 +30,8 @@ struct cxl_context *cxl_dev_context_init(struct pci_dev *dev)
return ERR_CAST(afu);

ctx = cxl_context_alloc();
- if (IS_ERR(ctx)) {
- rc = PTR_ERR(ctx);
- goto err_dev;
- }
+ if (!ctx)
+ return ERR_PTR(-ENOMEM);

ctx->kernelapi = true;

@@ -61,7 +59,6 @@ struct cxl_context *cxl_dev_context_init(struct pci_dev *dev)
kfree(mapping);
err_ctx:
kfree(ctx);
-err_dev:
return ERR_PTR(rc);
}
EXPORT_SYMBOL_GPL(cxl_dev_context_init);
--
2.9.3

2016-10-30 20:11:21

by walter harms

Subject: Re: [PATCH] cxl: Fix memory allocation failure test

Am 30.10.2016 20:35, schrieb Christophe JAILLET:
> 'cxl_context_alloc()' does not return an error pointer. It is just a
> shortcut for a call to 'kzalloc' with 'sizeof(struct cxl_context)' as the
> size parameter.
>
> So its return value should be compared with NULL.
> While fixing it, simplify a bit the code.
>
> Signed-off-by: Christophe JAILLET <[email protected]>
> ---
> un-compiled because I don't have the required cross build environment.
> ---
> drivers/misc/cxl/api.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
> index 2e5233b60971..2b88ad8a2a89 100644
> --- a/drivers/misc/cxl/api.c
> +++ b/drivers/misc/cxl/api.c
> @@ -30,10 +30,8 @@ struct cxl_context *cxl_dev_context_init(struct pci_dev *dev)
> return ERR_CAST(afu);
>
> ctx = cxl_context_alloc();
> - if (IS_ERR(ctx)) {
> - rc = PTR_ERR(ctx);
> - goto err_dev;
> - }
> + if (!ctx)
> + return ERR_PTR(-ENOMEM);
>

So far i see it is only used 2 times,
To avoid such problems it should be replaced with
kzalloc(sizeof(struct cxl_context), GFP_KERNEL); (from context.c)

or even better:
ctx = kzalloc(*ctx, GFP_KERNEL);

This way the error had been spotted much more early.

just my 2 cents,
re,
wh

> ctx->kernelapi = true;
>
> @@ -61,7 +59,6 @@ struct cxl_context *cxl_dev_context_init(struct pci_dev *dev)
> kfree(mapping);
> err_ctx:
> kfree(ctx);
> -err_dev:
> return ERR_PTR(rc);
> }
> EXPORT_SYMBOL_GPL(cxl_dev_context_init);

2016-10-31 06:16:57

by Andrew Donnellan

Subject: Re: [PATCH] cxl: Fix memory allocation failure test

On 31/10/16 06:35, Christophe JAILLET wrote:
> 'cxl_context_alloc()' does not return an error pointer. It is just a
> shortcut for a call to 'kzalloc' with 'sizeof(struct cxl_context)' as the
> size parameter.
>
> So its return value should be compared with NULL.
> While fixing it, simplify a bit the code.
>
> Signed-off-by: Christophe JAILLET <[email protected]>

Reviewed-by: Andrew Donnellan <[email protected]>

> ---
> un-compiled because I don't have the required cross build environment.

Compiles on my system!

--
Andrew Donnellan OzLabs, ADL Canberra
[email protected] IBM Australia Limited

2016-11-02 16:45:57

by Frederic Barrat

Subject: Re: [PATCH] cxl: Fix memory allocation failure test

Le 30/10/2016 ? 20:35, Christophe JAILLET a ?crit :
> 'cxl_context_alloc()' does not return an error pointer. It is just a
> shortcut for a call to 'kzalloc' with 'sizeof(struct cxl_context)' as the
> size parameter.
>
> So its return value should be compared with NULL.
> While fixing it, simplify a bit the code.
>
> Signed-off-by: Christophe JAILLET <[email protected]>
> ---


Acked-by: Frederic Barrat <[email protected]>

2016-11-16 01:56:56

by Ian Munsie

Subject: Re: [PATCH] cxl: Fix memory allocation failure test

Acked-by: Ian Munsie <[email protected]>

2016-11-22 00:34:58

by Michael Ellerman

Subject: Re: cxl: Fix memory allocation failure test

On Sun, 2016-10-30 at 19:35:57 UTC, Christophe Jaillet wrote:
> 'cxl_context_alloc()' does not return an error pointer. It is just a
> shortcut for a call to 'kzalloc' with 'sizeof(struct cxl_context)' as the
> size parameter.
>
> So its return value should be compared with NULL.
> While fixing it, simplify a bit the code.
>
> Signed-off-by: Christophe JAILLET <[email protected]>
> Reviewed-by: Andrew Donnellan <[email protected]>
> Acked-by: Frederic Barrat <[email protected]>
> Acked-by: Ian Munsie <[email protected]>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/5cd4f5cec2374d2c09299211d2b357

cheers