[FFmpeg-devel] [PATCH] fftools/ffmpeg_sched: fix race on SchFilter.send_finished (PR #21249)

[Niklas Haas via ffmpeg-devel <ffmpeg-devel@ffmpeg.org>]

PR #21249 opened by Niklas Haas (haasn)
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21249
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21249.patch

This logic was previously added to the scheduler. That commit added locking
(and rescheduling) when updating the corresponding `receive_finished` flag,
but missed doing the same for `send_finished`.

Fixes: fd1fd5850de4f3beb240422b67889bb776b26c77


>From d23908d12611b4873dbd1548de61e4a5ac45f277 Mon Sep 17 00:00:00 2001
From: Niklas Haas <git@haasn.dev>
Date: Sat, 20 Dec 2025 16:43:40 +0100
Subject: [PATCH] fftools/ffmpeg_sched: fix race on SchFilter.send_finished

This logic was previously added to the scheduler. That commit added locking
(and rescheduling) when updating the corresponding `receive_finished` flag,
but missed doing the same for `send_finished`.

Fixes: fd1fd5850de4f3beb240422b67889bb776b26c77
---
 fftools/ffmpeg_sched.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fftools/ffmpeg_sched.c b/fftools/ffmpeg_sched.c
index c5ee6971f1..862c002b85 100644
--- a/fftools/ffmpeg_sched.c
+++ b/fftools/ffmpeg_sched.c
@@ -2297,6 +2297,8 @@ static int send_to_filter(Scheduler *sch, SchFilterGraph *fg,
     if (frame)
         return tq_send(fg->queue, in_idx, frame);
 
+    pthread_mutex_lock(&sch->schedule_lock);
+
     if (!fg->inputs[in_idx].send_finished) {
         fg->inputs[in_idx].send_finished = 1;
         tq_send_finish(fg->queue, in_idx);
@@ -2304,7 +2306,11 @@ static int send_to_filter(Scheduler *sch, SchFilterGraph *fg,
         // close the control stream when all actual inputs are done
         if (atomic_fetch_add(&fg->nb_inputs_finished_send, 1) == fg->nb_inputs - 1)
             tq_send_finish(fg->queue, fg->nb_inputs);
+
+        schedule_update_locked(sch);
     }
+
+    pthread_mutex_unlock(&sch->schedule_lock);
     return 0;
 }
 
-- 
2.49.1

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