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From: Daniel Jacobowitz <drow@false.org>
To: David Lecomber <david@allinea.com>
Cc: gdb <gdb@sources.redhat.com>
Subject: Re: Itanium and GDB on 2.6.x kernels with pthreads
Date: Sat, 10 Sep 2005 15:29:00 -0000	[thread overview]
Message-ID: <20050910152915.GA2637@nevyn.them.org> (raw)
In-Reply-To: <1126110236.8094.85.camel@delmo.priv.wark.uk.streamline-computing.com>

On Wed, Sep 07, 2005 at 05:23:56PM +0100, David Lecomber wrote:
> Dear all,
> 
> Attached is a simple program, and simple script for GDB (current CVS,
> and previous versions)
> 
> gcc -o pf -g pf.c -lm -lpthread
> 
> gdb ./pf < gdb.script
> 
> The script is a break main and then 'next' four times, followed by quit.
> 
> On a 2.4.21 Itanium system, it's quick and quits happily.
> 
> On a 2.6.5 Itanium, it hangs during the later nexts.  Does anyone have a
> more recent Itanium they could try and see if this is a transient kernel
> issue?  

And on 2.4.27 (-dsa-itanium-smp, on one of Debian's machines,
merulo.debian.org) it hangs during the first next.  Thread debugging is
completely hosed.  That's using the installed GDB 6.3.

Using a GDB I've built from CVS I get the same result.

If I strace gdb, it segfaults at the run command.  It's not the same
problem you're seeing, because gdb is not consuming CPU.

CW:  waitpid 17370 received Trace/breakpoint trap (stopped)
CW:  waitpid 17370 received Trace/breakpoint trap (stopped)
CW:  waitpid 17370 received Illegal instruction (stopped)
[Thread debugging using libthread_db enabled]
[New Thread 16384 (LWP 17370)]
LLR: PTRACE_SINGLESTEP process 17370, 0 (resume event thread)
LLW: waitpid 17370 received Trace/breakpoint trap (stopped)
LLW: Candidate event Trace/breakpoint trap (stopped) in LWP 17370.
LLTA: PTRACE_PEEKUSER LWP 17370, 0, 0 (OK)
SEL: Select single-step LWP 17370
LLW: trap_ptid is process 17370.
LLR: PTRACE_CONT process 17370, 0 (resume event thread)
LLW: waitpid 17370 received Illegal instruction (stopped)
LLW: Candidate event Illegal instruction (stopped) in LWP 17370.
LLTA: PTRACE_PEEKUSER LWP 17370, 0, 0 (OK)
LLR: PTRACE_SINGLESTEP process 17370, 0 (resume event thread)

Those sigill's should not be there, should they?  Something is
seriously broken in ia64-land...  I get them even running
single-threaded, but they're ignored because they happen at
breakpoints.  But I'm not convinced that they don't indicate a real
problem somewhere.

And single-steps take me nowhere useful, and most local variables can't
be displayed.

Without knowing something useful about ia64, I don't think I can
usefully debug this, and there's no guarantee that it's even the same
problem you're seeing.  Sorry.

-- 
Daniel Jacobowitz
CodeSourcery, LLC

  parent reply	other threads:[~2005-09-10 15:29 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-09-07 16:27 David Lecomber
2005-09-07 22:15 ` Andreas Schwab
2005-09-09 14:48   ` David Lecomber
2005-09-10 15:29 ` Daniel Jacobowitz [this message]
2005-09-10 15:57   ` Daniel Jacobowitz
2005-09-16 10:36     ` David Lecomber

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