[PATCH libdrm v2] etnaviv: prevent deadlock in error path

[Philipp Zabel]

If drmPrimeFDToHandle fails in etna_bo_from_dmabuf, the function must
not return with the table_lock mutex held. There is no reason to call
drmPrimeFDToHandle under that lock, so just take the lock after trying
to obtain the handle.

Based on ceb70a6b1015 ("freedreno: prevent deadlock in error path").

Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>
---
v2: keep lock around drmPrimeFDToHandle call
---
 etnaviv/etnaviv_bo.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/etnaviv/etnaviv_bo.c b/etnaviv/etnaviv_bo.c
index 0cc3ab97..86fb894b 100644
--- a/etnaviv/etnaviv_bo.c
+++ b/etnaviv/etnaviv_bo.c
@@ -225,10 +225,15 @@ struct etna_bo *etna_bo_from_dmabuf(struct etna_device *dev, int fd)
 	int ret, size;
 	uint32_t handle;
 
+	/* take the lock before calling drmPrimeFDToHandle to avoid
+	 * racing against etna_bo_del, which might invalidate the
+	 * returned handle.
+	 */
 	pthread_mutex_lock(&table_lock);
 
 	ret = drmPrimeFDToHandle(dev->fd, fd, &handle);
 	if (ret) {
+		pthread_mutex_unlock(&table_lock);
 		return NULL;
 	}
 
-- 
2.11.0