"thread apply all bt full" gives blank in GDB

Question

I was trying to debug a multi-threaded process on a Linux server running Slackware 12 using GDB 6.6.

Once I attach and issue the command "thread apply all bt full" it comes back with nothing ( back on to the gdb prompt ).

Any idea why this happens?

Is the program run as another user or root? Are you running as root? — Duck, Jan 21 '10 at 20:54
I did try both. The the process is started as root but with a sudo invoking as a less privileged user. — ϹοδεMεδιϲ, Jan 21 '10 at 22:42
Last guess then - are you sure it is multi-threaded? Do you get any output just using "bt"? — Duck, Jan 21 '10 at 22:59
Please cut/paste your entire interaction with GDB. You may also wish to upgrade your GDB to current (7.0.1) release. — Employed Russian, Jan 23 '10 at 05:54
@Duck, yes it is multi threaded. when using "bt" i do get backtrace for one thread. — ϹοδεMεδιϲ, Jan 25 '10 at 06:35

score 1 · Answer 1 · answered Sep 13 '11 at 20:36

1

I ran into this problem and discovered that I can fix it as follows:

run "bt". this should show the backtrace of a thread, although maybe not the one you want.
now "cont".
hit ctrl+c. I see something like "[Switching to LWP %d]"
hit ctrl+c again. this breaks at the thread i want to see the backtrace of, but also seems to make "thread apply all bt full" start working.

answered Sep 13 '11 at 20:36

Michael

thanks for your post; I couldnt try this anymore as I have moved away from the particular environment & that particular process that I was having trouble with. +1 for the detailed post – ϹοδεMεδιϲ Sep 14 '11 at 07:12

score 0 · Accepted Answer · answered Oct 03 '10 at 08:19

0

Try last GDB version. 7.1 or 7.2. Everything should work.

answered Oct 03 '10 at 08:19

Marko Kevac

2 Answers2