Opened 20 years ago
Closed 19 years ago
#1396 closed defect (invalid)
crash of frontend on trying to enter live-tv
| Reported by: | simon kenyon | Owned by: | Isaac Richards |
|---|---|---|---|
| Priority: | minor | Milestone: | unknown |
| Component: | mythtv | Version: | |
| Severity: | medium | Keywords: | |
| Cc: | Ticket locked: | no |
Description
i've rebuilt entirely my two backends and this frontend (with symbols not stripped - they are gentoo linux boxes) in order to get proper backtraces.
on my frontend, i now get a seg fault on trying to enter live-tv.
all are running svn 9149
frontend is an amd64 master backend is an athlon slave backend is a pentium-m
the master frontend has the database and two pvr350s and a nexus-s the slave backend has two pvr350s
they were all running under gdb at the time (as per the documentation) i've included backtraces and logs from all three, although only the frontend crashed.
what more do i need to do?
Attachments (6)
Change History (11)
by , 20 years ago
| Attachment: | frontend_gdb.txt added |
|---|
comment:1 by , 20 years ago
if it makes any difference, all three are mounting the same recordings directory from a file server using nfs (with atimeo=0 as per recommendations on -dev).
comment:2 by , 20 years ago
i've done some further investigation and come across this qt bug report:
http://www.trolltech.com/developer/tasktracker.html?method=entry&id=82941
it seems that all versions of qt prior to qt 4.1 have a problem with calling mysql in threaded applications.
could this be what is causing my random (and not so random) crashes? however, it is surprising to me that there are not more reports of this type of problem.
right now i'm building qt to link against libmysqlclient_r (the reentrant library), rather that libmysqlclient (which it currently does). i'll update this ticket with the results of my tests when i get home from work later tonight.
comment:3 by , 20 years ago
this change has made a dramatic effect on the stability of my frontend/backend. i will recompile qt on my other backend and my various frontends and report back.
but for now i think this is worth further investigation.
if qt 4.1 were supported my myth then it would not require me to hack the qt build.
comment:4 by , 20 years ago
i've been just looking at the code and in particular the comments in changeset 5683 it suggests that particular combinations of mysql/qt will crash if a connection is closed and reopened. have a look at the comments in mythdbcon.h however, changset 8856 to mythdbcon.cpp seems to do exactly that this was added a month ago (9 days before 0.19 was released) - so maybe that is something to look at.
then again, i might be completely off target.
comment:5 by , 19 years ago
| Resolution: | → invalid |
|---|---|
| Status: | new → closed |
You're getting segfaults inside the MySQL libraries. Sounds like you didn't get something compiled right with Qt or MySQL. You may be using the non-threaded mysql stuff. This works fine for everyone else with Qt 3.x, so it should work fine for you. Closing this ticket as invalid since it's not a MythTV issue.
frontend gdb.txt