[PATCH] x86: call stop_machine_text_poke() on all CPUs

[PATCH] x86: call stop_machine_text_poke() on all CPUs

[Rabin Vincent]

It appears that stop_machine_text_poke() wants to be called on all CPUs,
like it's done from text_poke_smp().  Fix text_poke_smp_batch() to do
this.

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Rabin Vincent <rabin@rab.in>
---
 arch/x86/kernel/alternative.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index c638228..1f84794 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -738,5 +738,5 @@ void __kprobes text_poke_smp_batch(struct text_poke_param *params, int n)
 
 	atomic_set(&stop_machine_first, 1);
 	wrote_text = 0;
-	__stop_machine(stop_machine_text_poke, (void *)&tpp, NULL);
+	__stop_machine(stop_machine_text_poke, (void *)&tpp, cpu_online_mask);
 }
-- 
1.7.7

Re: [PATCH] x86: call stop_machine_text_poke() on all CPUs

[Masami Hiramatsu]

(2011/10/27 16:54), Rabin Vincent wrote:
> It appears that stop_machine_text_poke() wants to be called on all CPUs,
> like it's done from text_poke_smp().  Fix text_poke_smp_batch() to do
> this.

cpu_mask==NULL finally falls back to cpu_online_mask, but even though
it should be specified correctly.

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thank you!

> 
> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Jason Baron <jbaron@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Signed-off-by: Rabin Vincent <rabin@rab.in>
> ---
>  arch/x86/kernel/alternative.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
> index c638228..1f84794 100644
> --- a/arch/x86/kernel/alternative.c
> +++ b/arch/x86/kernel/alternative.c
> @@ -738,5 +738,5 @@ void __kprobes text_poke_smp_batch(struct text_poke_param *params, int n)
>  
>  	atomic_set(&stop_machine_first, 1);
>  	wrote_text = 0;
> -	__stop_machine(stop_machine_text_poke, (void *)&tpp, NULL);
> +	__stop_machine(stop_machine_text_poke, (void *)&tpp, cpu_online_mask);
>  }


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com

Re: [PATCH] x86: call stop_machine_text_poke() on all CPUs

[Rabin Vincent]

On Fri, Oct 28, 2011 at 11:28:39AM +0900, Masami Hiramatsu wrote:
> (2011/10/27 16:54), Rabin Vincent wrote:
> > It appears that stop_machine_text_poke() wants to be called on all CPUs,
> > like it's done from text_poke_smp().  Fix text_poke_smp_batch() to do
> > this.
> 
> cpu_mask==NULL finally falls back to cpu_online_mask, but even though
> it should be specified correctly.

Not quite.  Passing NULL to __stop_machine means that the function will
be called on any one CPU only, while passing cpu_online_mask means that
the function will be called on all CPUs.  So this patch is a behaviour
change/bug fix, not just a clarification.

Re: [PATCH] x86: call stop_machine_text_poke() on all CPUs

[Masami Hiramatsu]

(2011/10/28 21:30), Rabin Vincent wrote:
> On Fri, Oct 28, 2011 at 11:28:39AM +0900, Masami Hiramatsu wrote:
>> (2011/10/27 16:54), Rabin Vincent wrote:
>>> It appears that stop_machine_text_poke() wants to be called on all CPUs,
>>> like it's done from text_poke_smp().  Fix text_poke_smp_batch() to do
>>> this.
>>
>> cpu_mask==NULL finally falls back to cpu_online_mask, but even though
>> it should be specified correctly.
> 
> Not quite.  Passing NULL to __stop_machine means that the function will
> be called on any one CPU only, while passing cpu_online_mask means that
> the function will be called on all CPUs.  So this patch is a behaviour
> change/bug fix, not just a clarification.

Aah, Right! I just misunderstood.
Then this must be a bugfix!

Thanks!

-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com

[tip:x86/urgent] x86: Call stop_machine_text_poke() on all CPUs

[tip-bot for Rabin Vincent]

Commit-ID:  78345d2edc25e001558f3b7c85906f645d38d23c
Gitweb:     http://git.kernel.org/tip/78345d2edc25e001558f3b7c85906f645d38d23c
Author:     Rabin Vincent <rabin@rab.in>
AuthorDate: Thu, 27 Oct 2011 13:24:32 +0530
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Mon, 14 Nov 2011 13:05:15 +0100

x86: Call stop_machine_text_poke() on all CPUs

It appears that stop_machine_text_poke() wants to be called on all CPUs,
like it's done from text_poke_smp().  Fix text_poke_smp_batch() to do
this.

Signed-off-by: Rabin Vincent <rabin@rab.in>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Jason Baron <jbaron@redhat.com>
Link: http://lkml.kernel.org/r/1319702072-32676-1-git-send-email-rabin@rab.in
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/alternative.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index c638228..1f84794 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -738,5 +738,5 @@ void __kprobes text_poke_smp_batch(struct text_poke_param *params, int n)
 
 	atomic_set(&stop_machine_first, 1);
 	wrote_text = 0;
-	__stop_machine(stop_machine_text_poke, (void *)&tpp, NULL);
+	__stop_machine(stop_machine_text_poke, (void *)&tpp, cpu_online_mask);
 }