[PATCH 4.14 32/82] dma-buf/sync_file: Dont leak fences on merge failure

Greg Kroah-Hartman
2021-07-26T15:48:15Z

From: Jason Ekstrand <jason@jlekstrand.net>

commit ffe000217c5068c5da07ccb1c0f8cce7ad767435 upstream.

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@jlekstrand.net>
Reviewed-by: Christian König <christian.koenig@amd.com>
Fixes: a02b9dc90d84 ("dma-buf/sync_file: refactor fence storage in struct sync_file")
Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Cc: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210624174732.1754546-1-jason@jlekstrand.net
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/dma-buf/sync_file.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -220,8 +220,8 @@ static struct sync_file *sync_file_merge
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)
@@ -245,7 +245,7 @@ static struct sync_file *sync_file_merge
* 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];

@@ -286,15 +286,16 @@ static struct sync_file *sync_file_merge
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;