4 Jun
2012
4 Jun
'12
12:55 a.m.
On 06/03/2012 10:52 PM, Brendan Jones wrote:
On 06/01/2012 03:48 PM, David Adler wrote:
Compiling with -O0 also solves this error, so this could be a regression
in GCC.
On Fri, Jun 1, 2012 at 2:52 PM, Robin Gareus
wrote:
I've come a cross a jackdbus error which seems related. Basically
jackbus receives a SIGSEGV via the dbus-daemon on account of a bool
value not being 1 or 0.
It might have to do with Arch's compiler[-flags] and how jack2 uses
unions .. or scoping: JackGlobals vs Engine-Parameters.. although I
don't have an explanation.. all seems good.
Compiler flags (for 32bit) are, (from unaltered /etc/makepkg.conf):
CXXFLAGS="-march=i686 -mtune=generic -O2 -pipe -fstack-protector
--param=ssp-buffer-size=4 -D_FORTIFY_SOURCE=2"
A hunch: it could be caused by using
'server_ptr->verbose.b' (a union)
as boolean. The sever only checks "if (server_ptr->verbose.b)". The
union itself comprises other uninitialized values that could make it
evaluate to true (though it shouldn't, but maybe some compiler
optimization casts it to (int) instead of (bool) )
I know this is the '-users' list (I'm ccing jack-devel), but could
someone who experiences the problem try to track it down?
Basically just add a few printf()'s. Start at: common/JackControlAPI.cpp
- line 926 - before the call to "new JackServer(..)" add
printf("DEBUG verbose:
%s\n",(server_ptr->verbose.b)?"on":"off");
recompile, launch jackd. If it prints "verbose: on", sth is wrong with
parameter initialization in main() or with using unions. If it's "off"
the problem sits deeper:
DEBUG verbose: on
add a line just after common/JackServer.cpp line
66
printf("DEBUG verbose2:
%s\n",(JackGlobals::fVerbose)?"on":"off");
...
above, your line number didn't match exactly, so we seem to have
different versions (1.9.7 here). Thus, I wasn't exactly sure where to
add the prinf() and did the following:
...
JackServerGlobals::fUserCount = 1; // One user
printf("DEBUG verbose2:
%s\n",(JackGlobals::fVerbose)?"on":"off");
JackGlobals::fVerbose = verbose;
printf("DEBUG verbose3:
%s\n",(JackGlobals::fVerbose)?"on":"off");
}
which prints:
DEBUG verbose2: off
DEBUG verbose3: on
A crude test for the union() hunch would be to
change
common/JackControlAPI.h line 53:
replace
"union jackctl_parameter_value"
with
"struct jackctl_parameter_value"
and compile with '-fpermissive' like this:
CXXFLAGS="-fpermissive" ./waf configure
./waf
Again, mismatching line numbers. I assume you meant the line:
union jackctl_parameter_value verbose;
Changing that to struct fixes both issues I reported,
the verbose output and exit on last client close.
So we seem to be getting somewhere. Nice.
thanks Robin,
d