[PATCH v2] drm/vc4: Fix resource leak in 'vc4_get_hang_state_ioctl()' in error handling path

2017-05-12 Thread Christophe JAILLET
If one 'drm_gem_handle_create()' fails, we leak somes handles and some
memory.

In order to fix it:
  - move the 'free(bo_state)' at the end of the function so that it is also
called in the eror handling path. This has the side effect to also try 
to free it if the first 'kcalloc' fails. This is harmless.
  - add a new label, err_delete_handle, in order to delete already
allocated handles in error handling path
  - remove the now useless 'err' label

The way the code is now written will also delete the handles if the
'copy_to_user()' call fails.

Signed-off-by: Christophe JAILLET 
---
v2: reorder code and add a 'err_delete_handle' label in order to free
resources in the correct order and avoid NULL pointer dereference
---
 drivers/gpu/drm/vc4/vc4_gem.c | 15 +--
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c
index e9c381c42139..891c7a22cf81 100644
--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -111,8 +111,8 @@ vc4_get_hang_state_ioctl(struct drm_device *dev, void *data,
&handle);
 
if (ret) {
-   state->bo_count = i - 1;
-   goto err;
+   state->bo_count = i;
+   goto err_delete_handle;
}
bo_state[i].handle = handle;
bo_state[i].paddr = vc4_bo->base.paddr;
@@ -124,13 +124,16 @@ vc4_get_hang_state_ioctl(struct drm_device *dev, void 
*data,
 state->bo_count * sizeof(*bo_state)))
ret = -EFAULT;
 
-   kfree(bo_state);
+err_delete_handle:
+   if (ret) {
+   for (i = 0; i < state->bo_count; i++)
+   drm_gem_handle_delete(file_priv, bo_state[i].handle);
+   }
 
 err_free:
-
vc4_free_hang_state(dev, kernel_state);
+   kfree(bo_state);
 
-err:
return ret;
 }
 
-- 
2.11.0

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Re: [PATCH v2] drm/vc4: Fix resource leak in 'vc4_get_hang_state_ioctl()' in error handling path

2017-06-12 Thread Eric Anholt
Christophe JAILLET  writes:

> If one 'drm_gem_handle_create()' fails, we leak somes handles and some
> memory.
>
> In order to fix it:
>   - move the 'free(bo_state)' at the end of the function so that it is also
> called in the eror handling path. This has the side effect to also try 
> to free it if the first 'kcalloc' fails. This is harmless.
>   - add a new label, err_delete_handle, in order to delete already
> allocated handles in error handling path
>   - remove the now useless 'err' label

Reviewed and applied.  Thanks!


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