media dvb core fix feed leak on failed DMX_ADD_PID

[Rituparna Warwatkar]

#syz test

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+e9a1f5...@syzkaller.appspotmail.com
Tested-by: syzbot+e9a1f5...@syzkaller.appspotmail.com

Tested on:

commit: 3b029c03 Merge tag 'cgroup-for-7.2-rc3-fixes' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1207a8b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b80376788da8bcda
dashboard link: https://syzkaller.appspot.com/bug?extid=e9a1f5e196de6663631b
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch: https://syzkaller.appspot.com/x/patch.diff?x=10fcf432580000

Note: testing is done by a robot and is best-effort only.