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

[Christian König <christian.koenig@xxxxxxx>]

Sorry for the vacation and sick leave induced delay.

I've just pushed this to drm-misc-fixes.

Thanks,
Christian.

Am 24.06.21 um 21:43 schrieb Jason Ekstrand:
> I don't have drm-misc access.  Mind pushing?
>
> On Thu, Jun 24, 2021 at 12:59 PM Christian König
> <christian.koenig@xxxxxxx> 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@xxxxxxxxxxxxxx>
> > > Fixes: a02b9dc90d84 ("dma-buf/sync_file: refactor fence storage in struct sync_file")
> > > Cc: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>
> > > Cc: Christian König <christian.koenig@xxxxxxx>
> > Reviewed-by: Christian König <christian.koenig@xxxxxxx>
> >
> > > ---
> > >    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;