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Re: PATCH: Re: [RFHelp] Linux, threads, and regsets in thread_db
- From: "H . J . Lu" <hjl at lucon dot org>
- To: GDB <gdb at sourceware dot cygnus dot com>
- Date: Thu, 15 Nov 2001 08:55:08 -0800
- Subject: Re: PATCH: Re: [RFHelp] Linux, threads, and regsets in thread_db
- References: <20010924212808.A20851@nevyn.them.org> <20011003170848.A30843@lucon.org> <20011003211007.A12210@nevyn.them.org> <20011114134521.A25645@lucon.org> <20011115114841.A5118@nevyn.them.org>
On Thu, Nov 15, 2001 at 11:48:41AM -0500, Daniel Jacobowitz wrote:
> On Wed, Nov 14, 2001 at 01:45:21PM -0800, H . J . Lu wrote:
> > On Wed, Oct 03, 2001 at 09:10:07PM -0400, Daniel Jacobowitz wrote:
> > > > >
> > > >
> > > > How far have you gone on Linux/mips? I know gdb 5.1 doesn't work with
> > > > threads on Linux/mips. Does your change fix it? I'd like to clean up
> > > > glibc for mips on this.
> > >
> > > Yes. Debugging threads works reasonably well. I'm going to do more
> > > work about this in the next couple of months too, I think; after I go
> > > back to gdbserver for a little while.
> > I am still having problems with threads on mips. I cannot set break
> > point after target has run:
> > (gdb) run
> > ...
> > (gdb) b main
> > reading register sp (#29): No such process.
> > The problem is gdb tries to read sp register in thread mode. This patch
> > seems to work for me.
> This should not be a problem. It works fine for me. I'll step through
> it later tonight and try to figure out what the difference is from what
> you're seeing.
In my case, gdb in thread mode will cal "fetch_register" in infptrace.c.
Since nothing is running, I got
reading register sp (#29): No such process.
I don't know why it works for you.
> > Another problem is when I set a break point in a thread function, only
> > the first thread stops. I got
> > (gdb) b process
> > Breakpoint 1 at 0x400a38: file Examples/ex1.c, line 14.
> > (gdb) r
> > Starting program: /export/build/gnu/glibc/build-mipsel-linux/linuxthreads/ex1
> > [New Thread 1024 (LWP 26552)]
> > [New Thread 2049 (LWP 26569)]
> > [New Thread 1026 (LWP 26570)]
> > [Switching to Thread 1026 (LWP 26570)]
> > Breakpoint 1, process (arg=0x1000) at Examples/ex1.c:14
> > 14 fprintf (stderr, "Starting process %s\n", (char *) arg);
> > ...
> > Program received signal SIGTRAP, Trace/breakpoint trap.
> > [Switching to Thread 1024 (LWP 26552)]
> > 0x2ab8de24 in __syscall_rt_sigsuspend () at soinit.c:56
> > 56 soinit.c: No such file or directory.
> > But it may be a kernel bug.
> Something is suspicious here. The process in sigsuspend should have
> been stopped with SIGSTOP, not SIGTRAP... is this an example program
> from glibc?
Yes, linuxthreads/ex1 from glibc.
> > H.J.
> > ---
> > 2001-11-14 H.J. Lu (firstname.lastname@example.org)
> > * mips-tdep.c (heuristic_proc_desc): Read register only when
> > target is running.
> I can't see why this changes behavior in the way you're seeing. I'm
Why do you think that? Why does anyone want to read a register when
nothing is running?
> pretty sure it isn't right.