Re: kgdb for mainline kernel: core-lite [patch 1/3]

From: George Anzinger
Date: Mon Mar 08 2004 - 17:23:19 EST


Andrew Morton wrote:
"Amit S. Kale" <amitkale@xxxxxxxxxxxxx> wrote:

Let me just make sure we're taking about the same thing here. Are you
saying that with kgdb-lite, `info threads' is completely missing, or does
it just not work correctly with threads (as opposed to heavyweight
processes)?

info threads shows a list of threads. Heavy/light weight processes doesn't matter. Thread frame shown is incorrect.


It is? I haven't noticed any problems with it here. George recently
changed it to also display the process name in the gdb output, which is
valuable.


I looked at i386 dependent code again. Following code in it is incorrect. I never noticed it because this code is rarely used in full version of kgdb:

+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)


There is no such function in the stub in -mm kernels.


Present threads support code changes calling convention of do_IRQ. Most believe that to be an absolute no.


I see no such change in George's stub, unless I'm missing something again.

Amit and I went after the problem in rather different ways...


Since you consider it a must-have, I'll check whether above changes suggested by me make info threads listing correct in most cases.


The only problem I have with it is that sometimes after listing all threads
the debugger can lose control of the target and will start complaining
about communication errors. I assume the target has died. This happens
very rarely. Usually when you're about to find the bug ;)

Yeah, you won't believe how much work it took to detect that ;)

--
George Anzinger george@xxxxxxxxxx
High-res-timers: http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml

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