Re: [patch] s390*: watchpoints regression [repost]

Pedro Alves
2011-12-17T20:13:20Z

On Saturday 17 December 2011 19:56:32, Pedro Alves wrote:
> On Saturday 17 December 2011 19:44:54, Jan Kratochvil wrote:
> > On Sat, 17 Dec 2011 20:40:13 +0100, Pedro Alves wrote:
> > > In the loop that runs through the shell, fork-child.c:startup_inferior,
> > > nothing inserts breakpoints/watchpoints. So nothing ends up
> > > setting lwp->arch_private->debug_registers_changed, and so we should
> > > not be setting DR_CONTROL to 0 for the wrapper shell. Do you
> > > actually see it happen?
> >
> > I see it happenning. [attached]
>
> Ah, I forgot this:
>
> static void
> i386_linux_new_thread (struct lwp_info *lp)
> {
> struct arch_lwp_info *info = XCNEW (struct arch_lwp_info);
>
> info->debug_registers_changed = 1;
>
> lp->arch_private = info;
> }
>
> Hmm. I'm starting to think that the easiest is jut to
> go back at not calling new_thread for the first thread.
> Let me give that a try.

Seems to work fine. This should obsolete the s390 patch.

I think GDBserver has a similar problem with --wrapper.

--
Pedro Alves

2011-12-17 Pedro Alves <pedro@codesourcery.com>
Jan Kratochvil <jan.kratochvil@redhat.com>

* linux-nat.c (add_lwp): Don't call linux_nat_new_thread on the
first LWP.
* amd64-linux-nat.c (update_debug_registers_callback): Instantiate
`lwp->arch_private' if NULL.
(amd64_linux_prepare_to_resume): Do nothing if `lwp->arch_private'
is NULL.
* i386-linux-nat.c (update_debug_registers_callback): Instantiate
`lwp->arch_private' if NULL.
(i386_linux_prepare_to_resume): Do nothing if `lwp->arch_private'
is NULL.
---

gdb/amd64-linux-nat.c | 8 ++++++++
gdb/i386-linux-nat.c | 8 ++++++++
gdb/linux-nat.c | 2 +-
3 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c
index 288160b..6ee9596 100644
--- a/gdb/amd64-linux-nat.c
+++ b/gdb/amd64-linux-nat.c
@@ -343,6 +343,9 @@ amd64_linux_dr_get_status (void)
static int
update_debug_registers_callback (struct lwp_info *lwp, void *arg)
{
+ if (lwp->arch_private == NULL)
+ lwp->arch_private = XCNEW (struct arch_lwp_info);
+
/* The actual update is done later just before resuming the lwp, we
just mark that the registers need updating. */
lwp->arch_private->debug_registers_changed = 1;
@@ -386,6 +389,11 @@ amd64_linux_prepare_to_resume (struct lwp_info *lwp)
{
int clear_status = 0;

+ /* This is the main thread still going through the shell, or, no
+ watchpoint has been set yet. */
+ if (lwp->arch_private == NULL)
+ return;
+
if (lwp->arch_private->debug_registers_changed)
{
struct i386_debug_reg_state *state = i386_debug_reg_state ();
diff --git a/gdb/i386-linux-nat.c b/gdb/i386-linux-nat.c
index 190979b..3c56a22 100644
--- a/gdb/i386-linux-nat.c
+++ b/gdb/i386-linux-nat.c
@@ -715,6 +715,9 @@ i386_linux_dr_get_status (void)
static int
update_debug_registers_callback (struct lwp_info *lwp, void *arg)
{
+ if (lwp->arch_private == NULL)
+ lwp->arch_private = XCNEW (struct arch_lwp_info);
+
/* The actual update is done later just before resuming the lwp, we
just mark that the registers need updating. */
lwp->arch_private->debug_registers_changed = 1;
@@ -758,6 +761,11 @@ i386_linux_prepare_to_resume (struct lwp_info *lwp)
{
int clear_status = 0;

+ /* This is the main thread still going through the shell, or, no
+ watchpoint has been set yet. */
+ if (lwp->arch_private == NULL)
+ return;
+
if (lwp->arch_private->debug_registers_changed)
{
struct i386_debug_reg_state *state = i386_debug_reg_state ();
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 1cbfc44..2b1ecb7 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -1151,7 +1151,7 @@ add_lwp (ptid_t ptid)
lp->next = lwp_list;
lwp_list = lp;

- if (linux_nat_new_thread != NULL)
+ if (num_lwps (GET_PID (ptid)) > 1 && linux_nat_new_thread != NULL)
linux_nat_new_thread (lp);

return lp;