sync_file_ioctl_fence_info has a race between filling the status
of the underlying fences and the overall status of the sync_file.
If fence transitions in the time frame between its sync_fill_fence_info
and the later dma_fence_is_signaled for the sync_file, the returned
information is inconsistent showing non-signaled underlying fences but
an overall signaled state.
This patch changes sync_file_ioctl_fence_info to track what has been
encoded and using that as the overall sync_file status.
Tested-by: Vamsidhar Reddy Gaddam <vamsidhar.gad...@arm.com>
Signed-off-by: John Einar Reitan <john.rei...@arm.com>
Cc: Sumit Semwal <sumit.sem...@linaro.org>
Cc: Gustavo Padovan <gust...@padovan.org>
Cc: dri-devel@lists.freedesktop.org
---
Changes since v1 (thanks Chris Wilson):
- Replaced an unneeded local variable by writing directly to the struct
drivers/dma-buf/sync_file.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index 66fb40d0ebdb..03830634e141 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -383,7 +383,7 @@ static long sync_file_ioctl_merge(struct sync_file
*sync_file,
return err;
}
-static void sync_fill_fence_info(struct dma_fence *fence,
+static int sync_fill_fence_info(struct dma_fence *fence,
struct sync_fence_info *info)
{
strlcpy(info->obj_name, fence->ops->get_timeline_name(fence),
@@ -399,6 +399,8 @@ static void sync_fill_fence_info(struct dma_fence *fence,
test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags) ?
ktime_to_ns(fence->timestamp) :
ktime_set(0, 0);
+
+ return info->status;
}
static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
@@ -424,8 +426,12 @@ static long sync_file_ioctl_fence_info(struct sync_file
*sync_file,
* sync_fence_info and return the actual number of fences on
* info->num_fences.
*/
- if (!info.num_fences)
+ if (!info.num_fences) {
+ info.status = dma_fence_is_signaled(sync_file->fence);
goto no_fences;
+ } else {
+ info.status = 1;
+ }
if (info.num_fences < num_fences)
return -EINVAL;
@@ -435,8 +441,10 @@ static long sync_file_ioctl_fence_info(struct sync_file
*sync_file,
if (!fence_info)
return -ENOMEM;
- for (i = 0; i < num_fences; i++)
- sync_fill_fence_info(fences[i], &fence_info[i]);
+ for (i = 0; i < num_fences; i++) {
+ int status = sync_fill_fence_info(fences[i], &fence_info[i]);
+ info.status = info.status <= 0 ? info.status : status;
+ }
if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info,
size)) {
@@ -446,7 +454,6 @@ static long sync_file_ioctl_fence_info(struct sync_file
*sync_file,
no_fences:
sync_file_get_name(sync_file, info.name, sizeof(info.name));
- info.status = dma_fence_is_signaled(sync_file->fence);
info.num_fences = num_fences;
if (copy_to_user((void __user *)arg, &info, sizeof(info)))
--
2.13.6
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