On Wed, Feb 24, 2010 at 12:17:50PM -0600, Peter Steele wrote: > >You're going to need a debug version of libc, too. > >gdb won't be able to find a backtrace out of a libc function without it. > > What's the proper way to build a debug version of libc and the other > libraries? I tried this: > > export CFLAGS="-O0" > make buildworld > make installworld DESTDIR=/mydir > > and then copied libc.so.7 from /mydir/lib to the /lib dir on > my target system. I also replaced the ntpd binary with the debug version. > I can see that -O0 is being used in the various "cc" commands that are > generated, but libc still doesn't seem to be built properly. > When I attach to a hung ntpd process, I get this: > > # gdb /usr/sbin/ntpd -p 2113 > GNU gdb 6.1.1 [FreeBSD] > ... > Attaching to program: /usr/sbin/ntpd, process 2113 > Reading symbols from /lib/libm.so.5...(no debugging symbols found)...done. > ... > Reading symbols from /lib/libc.so.7...(no debugging symbols found)...done. > Loaded symbols for /lib/libc.so.7 > Reading symbols from /lib/libthr.so.3...(no debugging symbols found)...done. > ... > [Switching to Thread 8012041c0 (LWP 100283)] > 0x0000000800dbeddc in select () from /lib/libc.so.7 > (gdb) bt > #0 0x0000000800dbeddc in select () from /lib/libc.so.7 > #1 0x00000000004335de in ntpdmain () > #2 0x000000000043310b in main () > > So I'm getting some symbols from ntpd but I still can't see into select(). > I think not.
> It hangs in there forever so that's where I need to drill down further. > How do I get libc built with full debug symbols? > I haven't tried it by myself but think here is the way to go: put the following to /etc/make.conf and recompile needed libraries / ports. WITH_DEBUG=yes DEBUG_FLAGS=-g This should do the trick for both base and ports. > > [snip] > > If anyone has any clues at all as to what is causing this issue, > I'd appreciate the feedback. Here's the code that reproduces this behavior. > > #! /usr/bin/env python > import os > import threading > > class RunProc(threading.Thread): > def __init__(self, cmd): > threading.Thread.__init__(self) > self.cmd = cmd > > def run(self): > os.system(self.cmd) > > def main(): > RunProc("/usr/sbin/ntpd -g -q").start() > > if __name__ == "__main__": > main() > Mmm... Do other daemons (sshd, lpd, ...) also fail when started through this script? Normal commands (ls, ps) seem not affected. 0.02$, Alexey. _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"