[Intel-gfx] [PATCH] dma-buf/sync_file: Don't leak fences on merge failure

[Jason Ekstrand]

I don't have drm-misc access.  Mind pushing?

On Thu, Jun 24, 2021 at 12:59 PM Christian König
<christian.koenig at amd.com> wrote:
>
> Am 24.06.21 um 19:47 schrieb Jason Ekstrand:
> > Each add_fence() call does a dma_fence_get() on the relevant fence.  In
> > the error path, we weren't calling dma_fence_put() so all those fences
> > got leaked.  Also, in the krealloc_array failure case, we weren't
> > freeing the fences array.  Instead, ensure that i and fences are always
> > zero-initialized and dma_fence_put() all the fences and kfree(fences) on
> > every error path.
> >
> > Signed-off-by: Jason Ekstrand <jason at jlekstrand.net>
> > Fixes: a02b9dc90d84 ("dma-buf/sync_file: refactor fence storage in struct sync_file")
> > Cc: Gustavo Padovan <gustavo.padovan at collabora.co.uk>
> > Cc: Christian König <christian.koenig at amd.com>
>
> Reviewed-by: Christian König <christian.koenig at amd.com>
>
> > ---
> >   drivers/dma-buf/sync_file.c | 13 +++++++------
> >   1 file changed, 7 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
> > index 20d9bddbb985b..394e6e1e96860 100644
> > --- a/drivers/dma-buf/sync_file.c
> > +++ b/drivers/dma-buf/sync_file.c
> > @@ -211,8 +211,8 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
> >                                        struct sync_file *b)
> >   {
> >       struct sync_file *sync_file;
> > -     struct dma_fence **fences, **nfences, **a_fences, **b_fences;
> > -     int i, i_a, i_b, num_fences, a_num_fences, b_num_fences;
> > +     struct dma_fence **fences = NULL, **nfences, **a_fences, **b_fences;
> > +     int i = 0, i_a, i_b, num_fences, a_num_fences, b_num_fences;
> >
> >       sync_file = sync_file_alloc();
> >       if (!sync_file)
> > @@ -236,7 +236,7 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
> >        * If a sync_file can only be created with sync_file_merge
> >        * and sync_file_create, this is a reasonable assumption.
> >        */
> > -     for (i = i_a = i_b = 0; i_a < a_num_fences && i_b < b_num_fences; ) {
> > +     for (i_a = i_b = 0; i_a < a_num_fences && i_b < b_num_fences; ) {
> >               struct dma_fence *pt_a = a_fences[i_a];
> >               struct dma_fence *pt_b = b_fences[i_b];
> >
> > @@ -277,15 +277,16 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
> >               fences = nfences;
> >       }
> >
> > -     if (sync_file_set_fence(sync_file, fences, i) < 0) {
> > -             kfree(fences);
> > +     if (sync_file_set_fence(sync_file, fences, i) < 0)
> >               goto err;
> > -     }
> >
> >       strlcpy(sync_file->user_name, name, sizeof(sync_file->user_name));
> >       return sync_file;
> >
> >   err:
> > +     while (i)
> > +             dma_fence_put(fences[--i]);
> > +     kfree(fences);
> >       fput(sync_file->file);
> >       return NULL;
> >
>