avformat_open_input on dead UDP source link hangs after interrupt_callback signaled exit

[Marlon Mirchevski]

Udp source is not active.
After returning 1 from interrupt_callback (exit), avformat_open_input does not return.

Using Win32 dll from Zeranoe on W10 64bit, Microsoft compiler

2015-05-22 Working
​https://ffmpeg.zeranoe.com/builds/win32/shared/ffmpeg-20160522-git-566be4f-win32-shared.7z

2015-05-25 Not working
​https://ffmpeg.zeranoe.com/builds/win32/shared/ffmpeg-20160525-git-9591ca7-win32-shared.7z

How to reproduce:
GetTickCount used can be any time function returning miliseconds.

unsigned long TimePrev=0;
//callback
static int cb_open(void *ctx) 
{
 //timeout after 3 seconds
 if(GetTickCount() - TimePrev > 3000)
  {
   printf("---interrupt_cb: Exit\n");
   return 1;
  }
 return 0;
}


void main()
{
 avformat_network_init();
 AVFormatContext *pFmtCtx = avformat_alloc_context();
 pFmtCtx->interrupt_callback.callback = cb_open;
 pFmtCtx->interrupt_callback.opaque = 0;

 const char *url="udp://127.0.0.1:8000";
 printf("avformat_open_input %s\n", url);
 TimePrev=GetTickCount();
 int nRet=avformat_open_input(&pFmtCtx, url, NULL, NULL);
 //here never called

[superware]

Can a developer please check this (old) defect? it's very easy to reproduce... Thanks!

[Carl Eugen Hoyos]

Replying to superware:

Can a developer please check this (old) defect?

it's very easy to reproduce...

How can the issue be reproduced?

[superware]

Replying to cehoyos:

How can the issue be reproduced?

Hi cehoyos,

Simply open a non-existing UDP stream, such as "udp://127.0.0.1:8000", and avformat_open_input will hang even if the interrupt_callback.callback returns 1 ("During blocking operations, callback is called with opaque as parameter. If the callback returns 1, the blocking operation will be aborted.").

Actually all the details and code are supplied by Marlon above.

Thank you in advance.

[superware]

Replying to cehoyos:

How can the issue be reproduced?

Hi cehoyos, have you managed to reproduce the bug? Thanks!

[superware]

Marlon, do you have any new information regarding this issue?

[Carl Eugen Hoyos]

Which change introduced the regression?

[superware]

Thanks cehoyos.

Well, it seems Marlon found ffmpeg-20160522-git-566be4f-win32-shared.7z working but ffmpeg-20160525-git-9591ca7-win32-shared.7z not.

[Carl Eugen Hoyos]

Which of the 19 commits between 566be4f and 9591ca7 caused the regression?

[superware]

I'm not sure. Have you managed to reproduce?

[Carl Eugen Hoyos]

How can the issue be reproduced?

[superware]

Please see Marlon's code snippet in the description.

[Marlon Mirchevski]

This issue is fixed in version 4.0.2 or earlier.

I have just tested 32 and 64-bit versions from Zeranoe builds:
​https://ffmpeg.zeranoe.com/builds/win32/dev/ffmpeg-4.0.2-win32-dev.zip
​https://ffmpeg.zeranoe.com/builds/win64/dev/ffmpeg-4.0.2-win64-dev.zip
on Windows 7 and 10 and it's OK.
Thanks!