Hi,
On Friday, 8 December 2006 12:49, Rafael J. Wysocki wrote:
> On Friday, 8 December 2006 12:21, Pavel Machek wrote:
> > Hi!
> >
> > > > > > > ...after resume.
> > > > > >
> > > > > > This is because of how signal_wake_up() works, I think..
> > > > > >
> > > > > > > But I think it is right approach.
> > > > >
> > > > > Okay, with the appended patch applied everything seems to work and I don't
> > > > > see any undesirable side-effects.
> > > >
> > > > I promise to try it... tommorow. Looks very good to me.
> > >
> > > Unfortunately there's one problem with it.
> >
> > Well, IIRC it still had the 'bash reports vi stopped twice' problem.
>
> It doesn't do that for me, but ...
>
> > > To reproduce it I run "gdb /bin/cat", execute "run" in gdb and press ^Z twice
> > > to stop both processes. Next I suspend and resume and run "fg" to get the gdb
> > > back.and press "Enter" to get the prompt. Then, it turns out that the
> > > terminal echo doesn't work and "Enter" doesn't make it go to the next line.
> > > I can recover from this state by typing "fg+Enter" (with no echo) so that
> > > /bin/cat gets the continuation signal and it restores the terminal settings,
> > > apparently.
> >
> > I wonder if we should start a test suite ;-).
> >
> > > This means, however, that with this patch the behavior of a process (gdb)
> > > after the resume may be different to its normal behavior, which is wrong.
> >
> > Yep.
Okay, I think I know what to do so that it works. The above symptoms are not
present with the appended patch.
Greetings,
Rafael
Signed-off-by: Rafael J. Wysocki <rjw at sisk.pl>
---
kernel/power/process.c | 12 ++++++------
kernel/signal.c | 4 +++-
2 files changed, 9 insertions(+), 7 deletions(-)
Index: linux-2.6.19-rc6-mm2/kernel/power/process.c
===================================================================
--- linux-2.6.19-rc6-mm2.orig/kernel/power/process.c 2006-12-08 21:15:18.000000000 +0100
+++ linux-2.6.19-rc6-mm2/kernel/power/process.c 2006-12-08 21:47:23.000000000 +0100
@@ -28,8 +28,7 @@ static inline int freezeable(struct task
if ((p == current) ||
(p->flags & PF_NOFREEZE) ||
(p->exit_state == EXIT_ZOMBIE) ||
- (p->exit_state == EXIT_DEAD) ||
- (p->state == TASK_STOPPED))
+ (p->exit_state == EXIT_DEAD))
return 0;
return 1;
}
@@ -61,9 +60,12 @@ static inline void freeze_process(struct
unsigned long flags;
if (!freezing(p)) {
+ if (p->state == TASK_STOPPED)
+ force_sig_specific(SIGSTOP, p);
+
freeze(p);
spin_lock_irqsave(&p->sighand->siglock, flags);
- signal_wake_up(p, 0);
+ signal_wake_up(p, p->state == TASK_STOPPED);
spin_unlock_irqrestore(&p->sighand->siglock, flags);
}
}
@@ -103,9 +105,7 @@ static unsigned int try_to_freeze_tasks(
if (frozen(p))
continue;
- if (p->state == TASK_TRACED &&
- (frozen(p->parent) ||
- p->parent->state == TASK_STOPPED)) {
+ if (p->state == TASK_TRACED && frozen(p->parent)) {
cancel_freezing(p);
continue;
}
Index: linux-2.6.19-rc6-mm2/kernel/signal.c
===================================================================
--- linux-2.6.19-rc6-mm2.orig/kernel/signal.c 2006-12-08 21:15:18.000000000 +0100
+++ linux-2.6.19-rc6-mm2/kernel/signal.c 2006-12-08 21:15:30.000000000 +0100
@@ -1829,7 +1829,9 @@ finish_stop(int stop_count)
read_unlock(&tasklist_lock);
}
- schedule();
+ do {
+ schedule();
+ } while (try_to_freeze());
/*
* Now we don't run again until continued.
*/
