2015-07-20 15:06:14

by Sudip Mukherjee

[permalink] [raw]
Subject: [PATCH v2] drm/i915: remove unnecessary null test

While creating the debugfs file we are setting the inode->i_private to
dev. That same dev is passed to these functions as private of struct
seq_file via single_open(). So at this point it can never be NULL.

Signed-off-by: Sudip Mukherjee <[email protected]>
---

v1 was drm/i915: fix possible null pointer dereference

drivers/gpu/drm/i915/i915_debugfs.c | 9 ---------
1 file changed, 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index bc817da..63cb886 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4103,9 +4103,6 @@ static int i915_displayport_test_active_show(struct seq_file *m, void *data)
struct list_head *connector_list = &dev->mode_config.connector_list;
struct intel_dp *intel_dp;

- if (!dev)
- return -ENODEV;
-
list_for_each_entry(connector, connector_list, head) {

if (connector->connector_type !=
@@ -4150,9 +4147,6 @@ static int i915_displayport_test_data_show(struct seq_file *m, void *data)
struct list_head *connector_list = &dev->mode_config.connector_list;
struct intel_dp *intel_dp;

- if (!dev)
- return -ENODEV;
-
list_for_each_entry(connector, connector_list, head) {

if (connector->connector_type !=
@@ -4192,9 +4186,6 @@ static int i915_displayport_test_type_show(struct seq_file *m, void *data)
struct list_head *connector_list = &dev->mode_config.connector_list;
struct intel_dp *intel_dp;

- if (!dev)
- return -ENODEV;
-
list_for_each_entry(connector, connector_list, head) {

if (connector->connector_type !=
--
1.8.1.2


2015-07-20 15:31:14

by Daniel Vetter

[permalink] [raw]
Subject: Re: [Intel-gfx] [PATCH v2] drm/i915: remove unnecessary null test

On Mon, Jul 20, 2015 at 08:36:01PM +0530, Sudip Mukherjee wrote:
> While creating the debugfs file we are setting the inode->i_private to
> dev. That same dev is passed to these functions as private of struct
> seq_file via single_open(). So at this point it can never be NULL.
>
> Signed-off-by: Sudip Mukherjee <[email protected]>
> ---
>
> v1 was drm/i915: fix possible null pointer dereference

There's still one left in i915_displayport_test_active_write. Also please
mention the commit that introduced these and Cc: the author. Also please
Cc: Chris since he's commented on v1 of this patch.

Thanks, Daniel

>
> drivers/gpu/drm/i915/i915_debugfs.c | 9 ---------
> 1 file changed, 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index bc817da..63cb886 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -4103,9 +4103,6 @@ static int i915_displayport_test_active_show(struct seq_file *m, void *data)
> struct list_head *connector_list = &dev->mode_config.connector_list;
> struct intel_dp *intel_dp;
>
> - if (!dev)
> - return -ENODEV;
> -
> list_for_each_entry(connector, connector_list, head) {
>
> if (connector->connector_type !=
> @@ -4150,9 +4147,6 @@ static int i915_displayport_test_data_show(struct seq_file *m, void *data)
> struct list_head *connector_list = &dev->mode_config.connector_list;
> struct intel_dp *intel_dp;
>
> - if (!dev)
> - return -ENODEV;
> -
> list_for_each_entry(connector, connector_list, head) {
>
> if (connector->connector_type !=
> @@ -4192,9 +4186,6 @@ static int i915_displayport_test_type_show(struct seq_file *m, void *data)
> struct list_head *connector_list = &dev->mode_config.connector_list;
> struct intel_dp *intel_dp;
>
> - if (!dev)
> - return -ENODEV;
> -
> list_for_each_entry(connector, connector_list, head) {
>
> if (connector->connector_type !=
> --
> 1.8.1.2
>
> _______________________________________________
> Intel-gfx mailing list
> [email protected]
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

2015-07-21 06:41:29

by Sudip Mukherjee

[permalink] [raw]
Subject: Re: [Intel-gfx] [PATCH v2] drm/i915: remove unnecessary null test

On Mon, Jul 20, 2015 at 05:33:50PM +0200, Daniel Vetter wrote:
> On Mon, Jul 20, 2015 at 08:36:01PM +0530, Sudip Mukherjee wrote:
> > While creating the debugfs file we are setting the inode->i_private to
> > dev. That same dev is passed to these functions as private of struct
> > seq_file via single_open(). So at this point it can never be NULL.
> >
> > Signed-off-by: Sudip Mukherjee <[email protected]>
> > ---
> >
> > v1 was drm/i915: fix possible null pointer dereference
>
> There's still one left in i915_displayport_test_active_write.
I left it out intentionally as it was not used via single_open(). Will
include that and send v3.
>Also please mention the commit that introduced these and Cc: the author.
> Also please Cc: Chris since he's commented on v1 of this patch.
sure, Chris was Cc: in v2 and will Cc: him in v3 also.

regards
sudip

2015-07-21 07:35:01

by Daniel Vetter

[permalink] [raw]
Subject: Re: [Intel-gfx] [PATCH v2] drm/i915: remove unnecessary null test

On Tue, Jul 21, 2015 at 12:11:18PM +0530, Sudip Mukherjee wrote:
> On Mon, Jul 20, 2015 at 05:33:50PM +0200, Daniel Vetter wrote:
> > On Mon, Jul 20, 2015 at 08:36:01PM +0530, Sudip Mukherjee wrote:
> > > While creating the debugfs file we are setting the inode->i_private to
> > > dev. That same dev is passed to these functions as private of struct
> > > seq_file via single_open(). So at this point it can never be NULL.
> > >
> > > Signed-off-by: Sudip Mukherjee <[email protected]>
> > > ---
> > >
> > > v1 was drm/i915: fix possible null pointer dereference
> >
> > There's still one left in i915_displayport_test_active_write.
> I left it out intentionally as it was not used via single_open(). Will
> include that and send v3.

Well I didn't even read that far ;-) But ->write can only be called once
you opened the file, which means it will be set up already correctly too.
-Daniel

> >Also please mention the commit that introduced these and Cc: the author.
> > Also please Cc: Chris since he's commented on v1 of this patch.
> sure, Chris was Cc: in v2 and will Cc: him in v3 also.
>
> regards
> sudip
> _______________________________________________
> Intel-gfx mailing list
> [email protected]
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch