[mythtv-users] Hard crashes of mythtv backends

Michael Rice mikerice1969 at gmail.com
Mon Nov 5 18:53:31 UTC 2007

I've been running mythtv for about a year and a half (now on svn
trunk) and went through three different backend machines and from FC4
to FC6 now.   One nagging problem that persists is hard crashes of the
backend every so often.  On average it stays up for 7-10 days but
sometimes less.  Yesterday for instance I rebooted several times to
configure my HDHR on its own NIC.   The backend locked up (no ping, no
mouse/keyboard, requires power cycle to recover) at 5:00pm after an
uptime of only 3-4 hours.

My frontends on similar hardware and distros never lockup in this way.
 Even the slave backend/frontend does not crash this way.  The backend
(but not the slave backend) has IVTV tuners (2 pvr150's and a pvr350)
which is the major difference.  The crashes seem to happen when the
backend is busy at the top of the hour when recordings are starting
and rescheduling is occurring.  There is never anything suspicious in
the logs and the cards work fine.

Due to the hard crash I've always suspected a driver problem but
various updates to ivtv haven't seemed to help.  I just updated to
ivtv 1.0.x last night to see if that helps.

Do others with multiple ivtv cards have backends crashing like this?
I wonder if this is common or something specific to my setup.

I believe mythbackend runs as root on my backend.  Could mythbackend
running as root cause the machine to crash like this?  I wonder since
sometimes mythbackend crashes without locking the machine.  This
happens at similar times when the backend is busy at the start of the
hour.  I've never been able to track down these crashes but when I do
get a stack trace it is usually related to glibc/malloc corruption.

Is it possible to run mythbackend as a regular user on Fedora?  The
init code to start mythbackend that I use is probably from atrpms.
Has it changed recently to run as a non-privileged user?

Missing a minute or two of a recording while mythbackend restarts is
annoying but missing a whole night due to a hard crash is hard on the
WAF.  :(

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