[FFmpeg-devel] [PATCH] swscale/utils: fix leak on threaded ctx init failure

[Niklas Haas]

From: Niklas Haas <git at haasn.dev>

This count gets incremented after init succeeds, when it should be
incremented after *alloc* succeeds. Otherwise, we leak the context on
failure.

There are no negative consequences of incrementing for
allocated-but-not-initialized contexts, as the only functions that
reference it will, in the worst case, simply behave as if called on
allocated-but-not-initialized contexts, which is in line with expected
behavior when sws_init_context() fails.
---
 libswscale/utils.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/libswscale/utils.c b/libswscale/utils.c
index 12dba712c1..6ac5b202b0 100644
--- a/libswscale/utils.c
+++ b/libswscale/utils.c
@@ -2046,6 +2046,7 @@ static int context_init_threaded(SwsContext *c,
         if (!c->slice_ctx[i])
             return AVERROR(ENOMEM);
 
+        c->nb_slice_ctx++;
         c->slice_ctx[i]->parent = c;
 
         ret = av_opt_copy((void*)c->slice_ctx[i], (void*)c);
@@ -2058,8 +2059,6 @@ static int context_init_threaded(SwsContext *c,
         if (ret < 0)
             return ret;
 
-        c->nb_slice_ctx++;
-
         if (c->slice_ctx[i]->dither == SWS_DITHER_ED) {
             av_log(c, AV_LOG_VERBOSE,
                    "Error-diffusion dither is in use, scaling will be single-threaded.");
-- 
2.44.0