avcodec/ffv1dec: Remove redundant writes, fix races

Every modification of the data that is copied in update_thread_context() is a data race if it happens after ff_thread_finish_setup. ffv1dec's update_thread_context() simply uses memcpy for updating the new context, so that every modification of the src's context is a race. Some of these modifications are unnecessary: picture_number is write-only for the decoder and cur will be reset when decoding the next frame anyway. So remove them. And while just at it, also don't set cur for the slice contexts as this variable is write-only. Reviewed-by: Anton Khirnov <[email protected]> Signed-off-by: Andreas Rheinhardt <[email protected]>
SaschaVasarrhelyi · Dec 19, 2021 · 17605d1 · 17605d1
1 parent dfd06ee
commit 17605d1
Showing 1 changed file with 0 additions and 4 deletions.
diff --git a/libavcodec/ffv1dec.c b/libavcodec/ffv1dec.c
@@ -924,7 +924,6 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
             fs->c.bytestream_end = buf_p + v;
 
         fs->avctx = avctx;
-        fs->cur = p;
     }
 
     avctx->execute(avctx,
@@ -965,11 +964,8 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
     }
     ff_thread_report_progress(&f->picture, INT_MAX, 0);
 
-    f->picture_number++;
-
     if (f->last_picture.f)
         ff_thread_release_buffer(avctx, &f->last_picture);
-    f->cur = NULL;
     if ((ret = av_frame_ref(data, f->picture.f)) < 0)
         return ret;