For builts with CONFIG_DEBUG_OBJECTS_WORK=y kernels, the sscs.work
defined using INIT_WORK_ONSTACK() will be initialized by
debug_object_init_on_stack() for debug check in __init_work().
This commit therefore invoke destroy_work_on_stack() to free
sscs.work debug objects before smp_call_on_cpu() returns.

Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
---
 kernel/smp.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/smp.c b/kernel/smp.c
index cc13e73a887c..61f10f982341 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -1135,6 +1135,7 @@ int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
 
 	queue_work_on(cpu, system_wq, &sscs.work);
 	wait_for_completion(&sscs.done);
+	destroy_work_on_stack(&sscs.work);
 
 	return sscs.ret;
 }
-- 
2.17.1

On Thu, Jul 04, 2024 at 02:52:13PM +0800, Zqiang wrote:
> For builts with CONFIG_DEBUG_OBJECTS_WORK=y kernels, the sscs.work
> defined using INIT_WORK_ONSTACK() will be initialized by
> debug_object_init_on_stack() for debug check in __init_work().
> This commit therefore invoke destroy_work_on_stack() to free
> sscs.work debug objects before smp_call_on_cpu() returns.
> 
> Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>

I have queued this for testing.  My guess is that it should go to
mainline some other way, so:

Tested-by: Paul E. McKenney <paulmck@kernel.org>

> ---
>  kernel/smp.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/smp.c b/kernel/smp.c
> index cc13e73a887c..61f10f982341 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -1135,6 +1135,7 @@ int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
>  
>  	queue_work_on(cpu, system_wq, &sscs.work);
>  	wait_for_completion(&sscs.done);
> +	destroy_work_on_stack(&sscs.work);
>  
>  	return sscs.ret;
>  }
> -- 
> 2.17.1
>

>
> On Thu, Jul 04, 2024 at 02:52:13PM +0800, Zqiang wrote:
> > For builts with CONFIG_DEBUG_OBJECTS_WORK=y kernels, the sscs.work
> > defined using INIT_WORK_ONSTACK() will be initialized by
> > debug_object_init_on_stack() for debug check in __init_work().
> > This commit therefore invoke destroy_work_on_stack() to free
> > sscs.work debug objects before smp_call_on_cpu() returns.
> >
> > Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
>
> I have queued this for testing.  My guess is that it should go to
> mainline some other way, so:
>
> Tested-by: Paul E. McKenney <paulmck@kernel.org>

Thanks Paul for testing this change ;) .

>
> > ---
> >  kernel/smp.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/kernel/smp.c b/kernel/smp.c
> > index cc13e73a887c..61f10f982341 100644
> > --- a/kernel/smp.c
> > +++ b/kernel/smp.c
> > @@ -1135,6 +1135,7 @@ int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
> >
> >       queue_work_on(cpu, system_wq, &sscs.work);
> >       wait_for_completion(&sscs.done);
> > +     destroy_work_on_stack(&sscs.work);
> >
> >       return sscs.ret;
> >  }
> > --
> > 2.17.1
> >

The following commit has been merged into the smp/core branch of tip:

Commit-ID:     77aeb1b685f9db73d276bad4bb30d48505a6fd23
Gitweb:        https://git.kernel.org/tip/77aeb1b685f9db73d276bad4bb30d48505a6fd23
Author:        Zqiang <qiang.zhang1211@gmail.com>
AuthorDate:    Thu, 04 Jul 2024 14:52:13 +08:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 10 Jul 2024 22:40:39 +02:00

smp: Add missing destroy_work_on_stack() call in smp_call_on_cpu()

For CONFIG_DEBUG_OBJECTS_WORK=y kernels sscs.work defined by
INIT_WORK_ONSTACK() is initialized by debug_object_init_on_stack() for
the debug check in __init_work() to work correctly.

But this lacks the counterpart to remove the tracked object from debug
objects again, which will cause a debug object warning once the stack is
freed.

Add the missing destroy_work_on_stack() invocation to cure that.

[ tglx: Massaged changelog ]

Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20240704065213.13559-1-qiang.zhang1211@gmail.com

---
 kernel/smp.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/smp.c b/kernel/smp.c
index 1848357..aaffecd 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -1119,6 +1119,7 @@ int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)
 
 	queue_work_on(cpu, system_wq, &sscs.work);
 	wait_for_completion(&sscs.done);
+	destroy_work_on_stack(&sscs.work);
 
 	return sscs.ret;
 }