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

[Niklas Haas]

ffmpeg | branch: master | Niklas Haas <git at haasn.dev> | Tue Jul  9 16:41:01 2024 +0200| [4ec45aca36ff6c7c7767536ce7f4a855f8b37fb0] | committer: Niklas Haas

swscale/utils: fix leak on threaded ctx init failure

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.

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4ec45aca36ff6c7c7767536ce7f4a855f8b37fb0
---

 libswscale/utils.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/libswscale/utils.c b/libswscale/utils.c
index bc8d7627e2..c3154d82c1 100644
--- a/libswscale/utils.c
+++ b/libswscale/utils.c
@@ -2042,6 +2042,7 @@ 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);
@@ -2054,8 +2055,6 @@ 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.");