[FFmpeg-trac] #9385(avdevice:new): Potential error(e.g., resource leak, deadlock) due to the unreleased lock in function get_audio_config in FFmpeg/libavdevice/avfoundation.m

[FFmpeg]

#9385: Potential error(e.g., resource leak, deadlock) due to the unreleased lock
in function get_audio_config in  FFmpeg/libavdevice/avfoundation.m
----------------------------------+--------------------------------------
             Reporter:  cyeaa     |                     Type:  defect
               Status:  new       |                 Priority:  minor
            Component:  avdevice  |                  Version:  git-master
             Keywords:            |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
----------------------------------+--------------------------------------
 Hi,developers,thank you for your checking.The lock **ctx->frame_lock** may
 be not released correctly if the method **get_audio_config** returns at
 three error handling branches(line 697, line 735, line744). The relevant
 code is listed below and the problematic place is commented.

 source code link:
 https://github.com/FFmpeg/FFmpeg/blob/master/libavdevice/avfoundation.m#L686

 {{{#!div style="font-size: 80%"
 FFmpeg/libavdevice/avfoundation.m:
   {{{#!c++
   static void lock_frames(AVFContext* ctx)
   {
         pthread_mutex_lock(&ctx->frame_lock);
   }

   static void unlock_frames(AVFContext* ctx)
   {
         pthread_mutex_unlock(&ctx->frame_lock);
   }

   static int get_audio_config(AVFormatContext *s)
   {
         ...;

     lock_frames(ctx);

     if (!basic_desc) {
         av_log(s, AV_LOG_ERROR, "audio format not available\n");
         return 1; //line 697，lock leak: ctx->frame_lock is not released
 before return
     }

     ...;
     else {
         av_log(s, AV_LOG_ERROR, "audio format is not supported\n");
         return 1; //line 735, lock leak: ctx->frame_lock is not released
 before return
     }

     if (ctx->audio_non_interleaved) {
         CMBlockBufferRef block_buffer =
 CMSampleBufferGetDataBuffer(ctx->current_audio_frame);
         ctx->audio_buffer_size        =
 CMBlockBufferGetDataLength(block_buffer);
         ctx->audio_buffer             = av_malloc(ctx->audio_buffer_size);
         if (!ctx->audio_buffer) {
             av_log(s, AV_LOG_ERROR, "error allocating audio buffer\n");
             return 1; //line 744, lock leak: ctx->frame_lock is not
 released before return
         }
     }

     CFRelease(ctx->current_audio_frame);
     ctx->current_audio_frame = nil;

     unlock_frames(ctx);

     return 0;
   }
   }}}
 }}}

 Fixing suggestion:
 add **unlock_frames(ctx);** at all the above three branches.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9385>
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