[parisc-linux] tracing through sig handlers

[parisc-linux] tracing through sig handlers

[Richard Hirst]

Hi Alan,

If I do this:


Index: arch/parisc/kernel/signal.c
===================================================================
RCS file: /home/cvs/parisc/linux/arch/parisc/kernel/signal.c,v
retrieving revision 1.37
diff -u -r1.37 signal.c
--- signal.c	2001/02/09 14:39:08	1.37
+++ signal.c	2001/03/16 10:29:48
@@ -260,6 +260,8 @@
 		/* regs->iaoq is undefined in the syscall return path */
 		err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
 		err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
+		err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
+		err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
 #if DEBUG_SIG
 		printk("setup_sigcontext: iaoq %#lx/%#lx\n", regs->gr[31], regs->gr[31]);
 #endif


Then I can strace my little test prog. that sends itself a signal
while the signal is blocked, and then unblocks the signal.

I havn't worked out why this is only apparently necessary when a process
is being traced.

It makes things better with gdb also, but not perfect.  The problem
now is that when you try to step out of the signal handler the program
under test just runs on without stopping.  Previously it would have
crashed with an invalid iasq[].

Richard

[parisc-linux] Re: tracing through sig handlers

[Alan Modra]

On Fri, 16 Mar 2001, Richard Hirst wrote:

> I havn't worked out why this is only apparently necessary when a process
> is being traced.

I'm not even going to attempt to figure out why. :-)  Perhaps one of te
kernel gurus can shed some light.

> It makes things better with gdb also, but not perfect.  The problem
> now is that when you try to step out of the signal handler the program
> under test just runs on without stopping.

gdb is still confused about signal handler frames, and I haven't managed
to fix that today.  Too many other fires to fight.

Alan
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