kernel: INFO: task ffdecsawrapper:xxxxxx blocked for more than 240 seconds

Hello,

I am running (l)ubuntu 20.04 with kernel 5.4.0 with mythtv which I couldn't find any current deb packages of your projects for so this is what I did so far:

copied ppa-aap/cam/ffdecsawrapper to /usr/src
modified the build-script so that it builds the current git master branch of ffdecsawrapper
modified dkms scripts so that it builds the current git dvbloopback and dvb-core modules out-of-tree (takes a few seconds vs building the whole kernel for hours via ./configure script)
built everything
made a systemd script for ffdecsawrapper (replacing the initd script) which modprobes dvbloopback and runs ffdecsawrapper

Now, loading the dvbloopback module creates new adapters for all my dvb devices and ffdecsawrapper also starts as expected. But, every few minutes, there's something like this in syslog:

[91712.712587] INFO: task ffdecsawrapper:958168 blocked for more than 966 seconds.  
[91712.712591]       Tainted: G           OE     5.4.0-60-generic #67-Ubuntu 
[91712.712592] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[91712.712594] ffdecsawrapper  D    0 958168      1 0x00000000
[91712.712596] Call Trace:
[91712.712603]  __schedule+0x2e3/0x740
[91712.712606]  ? default_wake_function+0x12/0x20
[91712.712609]  schedule+0x42/0xb0
[91712.712611]  schedule_preempt_disabled+0xe/0x10
[91712.712612]  __mutex_lock.isra.0+0x182/0x4f0
[91712.712615]  ? ep_poll_callback+0x29d/0x2c0
[91712.712616]  __mutex_lock_slowpath+0x13/0x20
[91712.712617]  mutex_lock+0x2e/0x40
[91712.712622]  dvb_device_open+0x22/0xe0 [dvb_core]
[91712.712624]  chrdev_open+0xd3/0x1c0
[91712.712625]  ? cdev_default_release+0x20/0x20
[91712.712628]  do_dentry_open+0x143/0x3a0
[91712.712629]  vfs_open+0x2d/0x30
[91712.712631]  do_last+0x194/0x900
[91712.712633]  path_openat+0x8d/0x290
[91712.712635]  do_filp_open+0x91/0x100
[91712.712637]  ? __alloc_fd+0x46/0x150
[91712.712638]  do_sys_open+0x17e/0x290
[91712.712639]  __x64_sys_openat+0x20/0x30
[91712.712642]  do_syscall_64+0x57/0x190
[91712.712644]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[91712.712645] RIP: 0033:0x7fb2332ffad4
[91712.712650] Code: Bad RIP value.
[91712.712651] RSP: 002b:00007fb23364e6d0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
[91712.712652] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb2332ffad4
[91712.712653] RDX: 0000000000008802 RSI: 00007fb23364e7e0 RDI: 00000000ffffff9c
[91712.712654] RBP: 00007fb23364e7e0 R08: 0000000000000000 R09: 00007fb23364eaf0
[91712.712654] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000008802
[91712.712655] R13: 00007ffe5360310f R14: 0000562e1065b7e0 R15: 00007fb23364efc0

Do you have an idea what I did wrong there?

edit Sorry, my bad. Did something wrong. After re-compiling the dvb-core module and rebooting it works ;)

Thank you for that nice piece of software. It still does a good job ;)

bas-t / descrambler

kernel: INFO: task ffdecsawrapper:xxxxxx blocked for more than 240 seconds #20