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Re: [PATCH/RFC] Signals & single-stepping
- From: Daniel Jacobowitz <drow at false dot org>
- To: Mark Kettenis <mark dot kettenis at xs4all dot nl>
- Cc: gdb-patches at sourceware dot org
- Date: Wed, 30 Sep 2009 12:25:13 -0400
- Subject: Re: [PATCH/RFC] Signals & single-stepping
- References: <200909301440.n8UEevPb017814@brahms.sibelius.xs4all.nl>
On Wed, Sep 30, 2009 at 04:40:57PM +0200, Mark Kettenis wrote:
> A while ago Daniel made a change to infcmd.c which broke hitting
> breakpoints in signal handlers while single-stepping on OpenBSD (and
> probably other ptrace-based native targets):
>
> 2009-01-20 Daniel Jacobowitz <dan@codesourcery.com>
>
> PR gdb/9346
> * infcmd.c (signal_command): Do not specify a resume PC.
>
> The problem is that breakpoints are removed for single-stepping. So
> the diff below fixes things. Now it isn't clear to me if this
> approach doesn't reintroduce the problem from the PR that Daniel tried
> to fix.
>
> Comments?
Your patch doesn't reintroduce the problem from the PR, and the new
tests in interrupt.exp pass on x86_64-linux. I would really love
someone else to volunteer to review it though - trap_expected confuses
me horribly. I'd guess this change could lead to hitting (and
displaying) the breakpoint at the current PC a second time, which is
undesirable. On the other hand it might fix some of the signal tests
on software single-step targets...
>
>
> Index: infrun.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/infrun.c,v
> retrieving revision 1.410
> diff -u -p -r1.410 infrun.c
> --- infrun.c 29 Sep 2009 00:53:04 -0000 1.410
> +++ infrun.c 30 Sep 2009 12:55:46 -0000
> @@ -1604,6 +1604,11 @@ proceed (CORE_ADDR addr, enum target_sig
> else if (!signal_program[tp->stop_signal])
> tp->stop_signal = TARGET_SIGNAL_0;
>
> + if (tp->stop_signal != TARGET_SIGNAL_0) {
> + tp->trap_expected = 0;
> + insert_breakpoints ();
> + }
> +
> annotate_starting ();
>
> /* Make sure that output from GDB appears before output from the
>
--
Daniel Jacobowitz
CodeSourcery