[PATCH 1/2] staging: android: ion: Avoid NULL point in error path

[PATCH 1/2] staging: android: ion: Avoid NULL point in error path

[Yisheng Xie]

If we failed to create debugfs for ion at ion_device_create, the
debug_root of ion_device will be NULL, and then when try to create debug
file for shrinker of heap it will be create on the top of debugfs. If we
also failed to create this the debug file, it call dentry_path to found
the path of debug_root, then a NULL point will occur.

Fix this by avoiding call dentry_path, but show the debug name only when
failed to create debug file for shrinker.

Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
---
 drivers/staging/android/ion/ion.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index f480885..3e41644 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -570,13 +570,9 @@ void ion_device_add_heap(struct ion_heap *heap)
 		debug_file = debugfs_create_file(
 			debug_name, 0644, dev->debug_root, heap,
 			&debug_shrink_fops);
-		if (!debug_file) {
-			char buf[256], *path;
-
-			path = dentry_path(dev->debug_root, buf, 256);
-			pr_err("Failed to create heap shrinker debugfs at %s/%s\n",
-			       path, debug_name);
-		}
+		if (!debug_file)
+			pr_err("Failed to create ion heap shrinker debugfs at %s\n",
+			       debug_name);
 	}
 
 	dev->heap_cnt++;
-- 
1.7.12.4

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[PATCH 2/2] staging: android: ion: Remove lable debugfs_done

[Yisheng Xie]

When failed to create debug_root, we will go on initail other part of
ion, so we can just info this message to user and do not need a lable
to jump.

Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
---
 drivers/staging/android/ion/ion.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index 3e41644..70a70f5 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -601,12 +601,9 @@ static int ion_device_create(void)
 	}
 
 	idev->debug_root = debugfs_create_dir("ion", NULL);
-	if (!idev->debug_root) {
+	if (!idev->debug_root)
 		pr_err("ion: failed to create debugfs root directory.\n");
-		goto debugfs_done;
-	}
 
-debugfs_done:
 	idev->buffers = RB_ROOT;
 	mutex_init(&idev->buffer_lock);
 	init_rwsem(&idev->lock);
-- 
1.7.12.4

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Re: [PATCH 1/2] staging: android: ion: Avoid NULL point in error path

[Laura Abbott]

On 02/01/2018 04:34 AM, Yisheng Xie wrote:
> If we failed to create debugfs for ion at ion_device_create, the
> debug_root of ion_device will be NULL, and then when try to create debug
> file for shrinker of heap it will be create on the top of debugfs. If we
> also failed to create this the debug file, it call dentry_path to found
> the path of debug_root, then a NULL point will occur.
> 
> Fix this by avoiding call dentry_path, but show the debug name only when
> failed to create debug file for shrinker.
> 

Acked-by: Laura Abbott <labbott@redhat.com>

> Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
> ---
>   drivers/staging/android/ion/ion.c | 10 +++-------
>   1 file changed, 3 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
> index f480885..3e41644 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -570,13 +570,9 @@ void ion_device_add_heap(struct ion_heap *heap)
>   		debug_file = debugfs_create_file(
>   			debug_name, 0644, dev->debug_root, heap,
>   			&debug_shrink_fops);
> -		if (!debug_file) {
> -			char buf[256], *path;
> -
> -			path = dentry_path(dev->debug_root, buf, 256);
> -			pr_err("Failed to create heap shrinker debugfs at %s/%s\n",
> -			       path, debug_name);
> -		}
> +		if (!debug_file)
> +			pr_err("Failed to create ion heap shrinker debugfs at %s\n",
> +			       debug_name);
>   	}
>   
>   	dev->heap_cnt++;
> 

Re: [PATCH 2/2] staging: android: ion: Remove lable debugfs_done

[Laura Abbott]

On 02/01/2018 04:34 AM, Yisheng Xie wrote:
> When failed to create debug_root, we will go on initail other part of
> ion, so we can just info this message to user and do not need a lable
> to jump.
> 

Acked-by: Laura Abbott <labbott@redhat.com>

> Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
> ---
>   drivers/staging/android/ion/ion.c | 5 +----
>   1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
> index 3e41644..70a70f5 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -601,12 +601,9 @@ static int ion_device_create(void)
>   	}
>   
>   	idev->debug_root = debugfs_create_dir("ion", NULL);
> -	if (!idev->debug_root) {
> +	if (!idev->debug_root)
>   		pr_err("ion: failed to create debugfs root directory.\n");
> -		goto debugfs_done;
> -	}
>   
> -debugfs_done:
>   	idev->buffers = RB_ROOT;
>   	mutex_init(&idev->buffer_lock);
>   	init_rwsem(&idev->lock);
> 

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Re: [PATCH 1/2] staging: android: ion: Avoid NULL point in error path

[Yisheng Xie]

Hi Greg,

JFYI, I have rebase this patchset to v4.15-rc1.[1]

[1] https://lkml.org/lkml/2018/2/12/204

Thanks
Yisheng

On 2018/2/1 20:34, Yisheng Xie wrote:
> If we failed to create debugfs for ion at ion_device_create, the
> debug_root of ion_device will be NULL, and then when try to create debug
> file for shrinker of heap it will be create on the top of debugfs. If we
> also failed to create this the debug file, it call dentry_path to found
> the path of debug_root, then a NULL point will occur.
> 
> Fix this by avoiding call dentry_path, but show the debug name only when
> failed to create debug file for shrinker.
> 
> Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
> ---
>  drivers/staging/android/ion/ion.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
> index f480885..3e41644 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -570,13 +570,9 @@ void ion_device_add_heap(struct ion_heap *heap)
>  		debug_file = debugfs_create_file(
>  			debug_name, 0644, dev->debug_root, heap,
>  			&debug_shrink_fops);
> -		if (!debug_file) {
> -			char buf[256], *path;
> -
> -			path = dentry_path(dev->debug_root, buf, 256);
> -			pr_err("Failed to create heap shrinker debugfs at %s/%s\n",
> -			       path, debug_name);
> -		}
> +		if (!debug_file)
> +			pr_err("Failed to create ion heap shrinker debugfs at %s\n",
> +			       debug_name);
>  	}
>  
>  	dev->heap_cnt++;
> 

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