Messages in this thread | | | From | "Amit S. Kale" <> | Subject | Re: kgdb for mainline kernel: core-lite [patch 1/3] | Date | Mon, 8 Mar 2004 16:50:18 +0530 |
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On Monday 08 Mar 2004 4:37 pm, Andrew Morton wrote: > "Amit S. Kale" <amitkale@emsyssoft.com> wrote: > > On Monday 08 Mar 2004 3:56 pm, Andrew Morton wrote: > > > "Amit S. Kale" <amitkale@emsyssoft.com> wrote: > > > > Here are features that are present only in full kgdb: > > > > 1. Thread support (aka info threads) > > > > > > argh, disaster. I discussed this with Tom a week or so ago when it > > > looked like this it was being chopped out and I recall being told that > > > the discussion was referring to something else. > > > > > > Ho-hum, sorry. Can we please put this back in? > > > > Err., well this is one of the particularly dirty parts of kgdb. That's > > why it's been kept away. It takes care of correct thread backtraces in > > some rare cases. > > 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.
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) .... + gdb_regs[_EBP] = *(int *)p->thread.esp;
We can't guss ebp this way. This line should be removed.
+ gdb_regs[_DS] = __KERNEL_DS; + gdb_regs[_ES] = __KERNEL_DS; + gdb_regs[_PS] = 0; + gdb_regs[_CS] = __KERNEL_CS; + gdb_regs[_PC] = p->thread.eip; + gdb_regs[_ESP] = p->thread.esp;
This should be gdb_regs[_ESP] = &p->thread.esp
> > > If you consider it an absolutely must, we can do something so that the > > dirty part is kept away and info threads almost always works. > > Yes, I'd consider `info threads' support a must-have. I'm rather surprised > that others do not?
Present threads support code changes calling convention of do_IRQ. Most believe that to be an absolute no.
Since you consider it a must-have, I'll check whether above changes suggested by me make info threads listing correct in most cases.
-Amit
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