[PATCH -stable] modules fix incorrect percpu usage

[PATCH -stable] modules fix incorrect percpu usage

[Mathieu Desnoyers]

Should use per_cpu_ptr() to obfuscate the per cpu pointers (RELOC_HIDE is needed
for per cpu pointers).

Introduced by commit:

module.c: commit 6b588c18f8dacfa6d7957c33c5ff832096e752d3

This patch should be queued for the stable branch, for kernels 2.6.29.x to
2.6.33.x.
(tested on 2.6.33.1 x86_64)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Randy Dunlap <randy.dunlap@oracle.com>
CC: Eric Dumazet <dada1@cosmosbay.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Tejun Heo <tj@kernel.org>
CC: Ingo Molnar <mingo@elte.hu>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Greg Kroah-Hartman <gregkh@suse.de>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: stable <stable@kernel.org>
---
 kernel/module.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6-lttng/kernel/module.c
===================================================================
--- linux-2.6-lttng.orig/kernel/module.c	2010-03-29 23:47:05.000000000 -0400
+++ linux-2.6-lttng/kernel/module.c	2010-03-29 23:47:27.000000000 -0400
@@ -412,7 +412,7 @@ static void percpu_modcopy(void *pcpudes
 	int cpu;
 
 	for_each_possible_cpu(cpu)
-		memcpy(pcpudest + per_cpu_offset(cpu), from, size);
+		memcpy(per_cpu_ptr(pcpudest, cpu), from, size);
 }
 
 #else /* ... !CONFIG_SMP */

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

Re: [PATCH] modules fix incorrect percpu usage

[Mathieu Desnoyers]

* Mathieu Desnoyers (mathieu.desnoyers@efficios.com) wrote:
> Should use per_cpu_ptr() to obfuscate the per cpu pointers (RELOC_HIDE is needed
> for per cpu pointers).
> 
> Introduced by commit:
> 
> module.c: commit 6b588c18f8dacfa6d7957c33c5ff832096e752d3
> 
> This patch should be queued for the stable branch, for kernels 2.6.29.x to
> 2.6.33.x.
> (tested on 2.6.33.1 x86_64)

It's actually needed for mainline too (2.6.34-rc2).

Thanks,

Mathieu

> 
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> CC: Randy Dunlap <randy.dunlap@oracle.com>
> CC: Eric Dumazet <dada1@cosmosbay.com>
> CC: Rusty Russell <rusty@rustcorp.com.au>
> CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
> CC: Tejun Heo <tj@kernel.org>
> CC: Ingo Molnar <mingo@elte.hu>
> CC: Andrew Morton <akpm@linux-foundation.org>
> CC: Linus Torvalds <torvalds@linux-foundation.org>
> CC: Greg Kroah-Hartman <gregkh@suse.de>
> CC: Steven Rostedt <rostedt@goodmis.org>
> CC: stable <stable@kernel.org>
> ---
>  kernel/module.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> Index: linux-2.6-lttng/kernel/module.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/module.c	2010-03-29 23:47:05.000000000 -0400
> +++ linux-2.6-lttng/kernel/module.c	2010-03-29 23:47:27.000000000 -0400
> @@ -412,7 +412,7 @@ static void percpu_modcopy(void *pcpudes
>  	int cpu;
>  
>  	for_each_possible_cpu(cpu)
> -		memcpy(pcpudest + per_cpu_offset(cpu), from, size);
> +		memcpy(per_cpu_ptr(pcpudest, cpu), from, size);
>  }
>  
>  #else /* ... !CONFIG_SMP */
> 
> -- 
> Mathieu Desnoyers
> Operating System Efficiency R&D Consultant
> EfficiOS Inc.
> http://www.efficios.com

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

Re: [PATCH] modules fix incorrect percpu usage

[Steven Rostedt]

On Mon, 2010-03-29 at 23:36 -0400, Mathieu Desnoyers wrote:
> * Mathieu Desnoyers (mathieu.desnoyers@efficios.com) wrote:
> > Should use per_cpu_ptr() to obfuscate the per cpu pointers (RELOC_HIDE is needed
> > for per cpu pointers).
> > 
> > Introduced by commit:
> > 
> > module.c: commit 6b588c18f8dacfa6d7957c33c5ff832096e752d3
> > 
> > This patch should be queued for the stable branch, for kernels 2.6.29.x to
> > 2.6.33.x.
> > (tested on 2.6.33.1 x86_64)
> 
> It's actually needed for mainline too (2.6.34-rc2).

Then all you need to do is submit it for mainline with a 
"Cc: stable@kernel.org" as you did below. It will then automatically be
added to the stable queue when Linus pulls it.

-- Steve

> 
> Thanks,
> 
> Mathieu
> 
> > 
> > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> > CC: Randy Dunlap <randy.dunlap@oracle.com>
> > CC: Eric Dumazet <dada1@cosmosbay.com>
> > CC: Rusty Russell <rusty@rustcorp.com.au>
> > CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > CC: Tejun Heo <tj@kernel.org>
> > CC: Ingo Molnar <mingo@elte.hu>
> > CC: Andrew Morton <akpm@linux-foundation.org>
> > CC: Linus Torvalds <torvalds@linux-foundation.org>
> > CC: Greg Kroah-Hartman <gregkh@suse.de>
> > CC: Steven Rostedt <rostedt@goodmis.org>
> > CC: stable <stable@kernel.org>
> > ---
> >  kernel/module.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > 

Re: [PATCH] modules fix incorrect percpu usage

[Mathieu Desnoyers]

* Steven Rostedt (rostedt@goodmis.org) wrote:
> On Mon, 2010-03-29 at 23:36 -0400, Mathieu Desnoyers wrote:
> > * Mathieu Desnoyers (mathieu.desnoyers@efficios.com) wrote:
> > > Should use per_cpu_ptr() to obfuscate the per cpu pointers (RELOC_HIDE is needed
> > > for per cpu pointers).
> > > 
> > > Introduced by commit:
> > > 
> > > module.c: commit 6b588c18f8dacfa6d7957c33c5ff832096e752d3
> > > 
> > > This patch should be queued for the stable branch, for kernels 2.6.29.x to
> > > 2.6.33.x.
> > > (tested on 2.6.33.1 x86_64)
> > 
> > It's actually needed for mainline too (2.6.34-rc2).
> 
> Then all you need to do is submit it for mainline with a 
> "Cc: stable@kernel.org" as you did below. It will then automatically be
> added to the stable queue when Linus pulls it.

OK, thanks for the info.

Mathieu

> 
> -- Steve
> 
> > 
> > Thanks,
> > 
> > Mathieu
> > 
> > > 
> > > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> > > CC: Randy Dunlap <randy.dunlap@oracle.com>
> > > CC: Eric Dumazet <dada1@cosmosbay.com>
> > > CC: Rusty Russell <rusty@rustcorp.com.au>
> > > CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > > CC: Tejun Heo <tj@kernel.org>
> > > CC: Ingo Molnar <mingo@elte.hu>
> > > CC: Andrew Morton <akpm@linux-foundation.org>
> > > CC: Linus Torvalds <torvalds@linux-foundation.org>
> > > CC: Greg Kroah-Hartman <gregkh@suse.de>
> > > CC: Steven Rostedt <rostedt@goodmis.org>
> > > CC: stable <stable@kernel.org>
> > > ---
> > >  kernel/module.c |    2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > 
> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

Re: [stable] [PATCH] modules fix incorrect percpu usage

[Greg KH]

On Tue, Mar 30, 2010 at 09:50:47AM -0400, Mathieu Desnoyers wrote:
> * Steven Rostedt (rostedt@goodmis.org) wrote:
> > On Mon, 2010-03-29 at 23:36 -0400, Mathieu Desnoyers wrote:
> > > * Mathieu Desnoyers (mathieu.desnoyers@efficios.com) wrote:
> > > > Should use per_cpu_ptr() to obfuscate the per cpu pointers (RELOC_HIDE is needed
> > > > for per cpu pointers).
> > > > 
> > > > Introduced by commit:
> > > > 
> > > > module.c: commit 6b588c18f8dacfa6d7957c33c5ff832096e752d3
> > > > 
> > > > This patch should be queued for the stable branch, for kernels 2.6.29.x to
> > > > 2.6.33.x.
> > > > (tested on 2.6.33.1 x86_64)
> > > 
> > > It's actually needed for mainline too (2.6.34-rc2).
> > 
> > Then all you need to do is submit it for mainline with a 
> > "Cc: stable@kernel.org" as you did below. It will then automatically be
> > added to the stable queue when Linus pulls it.
> 
> OK, thanks for the info.

And I need to wait until it goes into Linus's tree before it can be
applied to the stable tree.  This hasn't happened yet, right?

thanks,

greg k-h

Re: [stable] [PATCH] modules fix incorrect percpu usage

[Mathieu Desnoyers]

* Greg KH (greg@kroah.com) wrote:
> On Tue, Mar 30, 2010 at 09:50:47AM -0400, Mathieu Desnoyers wrote:
> > * Steven Rostedt (rostedt@goodmis.org) wrote:
> > > On Mon, 2010-03-29 at 23:36 -0400, Mathieu Desnoyers wrote:
> > > > * Mathieu Desnoyers (mathieu.desnoyers@efficios.com) wrote:
> > > > > Should use per_cpu_ptr() to obfuscate the per cpu pointers (RELOC_HIDE is needed
> > > > > for per cpu pointers).
> > > > > 
> > > > > Introduced by commit:
> > > > > 
> > > > > module.c: commit 6b588c18f8dacfa6d7957c33c5ff832096e752d3
> > > > > 
> > > > > This patch should be queued for the stable branch, for kernels 2.6.29.x to
> > > > > 2.6.33.x.
> > > > > (tested on 2.6.33.1 x86_64)
> > > > 
> > > > It's actually needed for mainline too (2.6.34-rc2).
> > > 
> > > Then all you need to do is submit it for mainline with a 
> > > "Cc: stable@kernel.org" as you did below. It will then automatically be
> > > added to the stable queue when Linus pulls it.
> > 
> > OK, thanks for the info.
> 
> And I need to wait until it goes into Linus's tree before it can be
> applied to the stable tree.  This hasn't happened yet, right?
> 
> thanks,
> 
> greg k-h

Same here, for module.c fix. Feel free to choose between this fix or the
corresponding refactoring from Tejun.


modules fix incorrect percpu usage

Should use per_cpu_ptr() to obfuscate the per cpu pointers (RELOC_HIDE is needed
for per cpu pointers).

Introduced by commit:

module.c: commit 6b588c18f8dacfa6d7957c33c5ff832096e752d3

This patch should be queued for the stable branch, for kernels 2.6.29.x to
2.6.33.x.  (tested on 2.6.33.1 x86_64)

Mainline does not need this fix, as commit
259354deaaf03d49a02dbb9975d6ec2a54675672 fixed the problem by refactoring.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Randy Dunlap <randy.dunlap@oracle.com>
CC: Eric Dumazet <dada1@cosmosbay.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Tejun Heo <tj@kernel.org>
CC: Ingo Molnar <mingo@elte.hu>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Greg Kroah-Hartman <gregkh@suse.de>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: stable <stable@kernel.org>
---
 kernel/module.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux.trees.git/kernel/module.c
===================================================================
--- linux.trees.git.orig/kernel/module.c	2010-03-27 11:27:23.000000000 -0400
+++ linux.trees.git/kernel/module.c	2010-03-30 09:48:41.000000000 -0400
@@ -405,7 +405,7 @@ static void percpu_modcopy(void *pcpudes
 	int cpu;
 
 	for_each_possible_cpu(cpu)
-		memcpy(pcpudest + per_cpu_offset(cpu), from, size);
+		memcpy(per_cpu_ptr(pcpudest, cpu), from, size);
 }
 
 #else /* ... !CONFIG_SMP */


-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com

Re: [stable] [PATCH] modules fix incorrect percpu usage

[Tejun Heo]

Hello,

On 04/20/2010 04:34 PM, Mathieu Desnoyers wrote:
> Same here, for module.c fix. Feel free to choose between this fix or the
> corresponding refactoring from Tejun.

Please take this one for -stable.  I don't think the percpu
refactoring is worthwhile to backport to -stable.  It only affects
debug feature and the worst outcome is spurious warning messages.

Thanks.

-- 
tejun

Re: [stable] [PATCH] modules fix incorrect percpu usage

[Greg KH]

On Tue, Apr 20, 2010 at 10:34:57AM -0400, Mathieu Desnoyers wrote:
> * Greg KH (greg@kroah.com) wrote:
> > On Tue, Mar 30, 2010 at 09:50:47AM -0400, Mathieu Desnoyers wrote:
> > > * Steven Rostedt (rostedt@goodmis.org) wrote:
> > > > On Mon, 2010-03-29 at 23:36 -0400, Mathieu Desnoyers wrote:
> > > > > * Mathieu Desnoyers (mathieu.desnoyers@efficios.com) wrote:
> > > > > > Should use per_cpu_ptr() to obfuscate the per cpu pointers (RELOC_HIDE is needed
> > > > > > for per cpu pointers).
> > > > > > 
> > > > > > Introduced by commit:
> > > > > > 
> > > > > > module.c: commit 6b588c18f8dacfa6d7957c33c5ff832096e752d3
> > > > > > 
> > > > > > This patch should be queued for the stable branch, for kernels 2.6.29.x to
> > > > > > 2.6.33.x.
> > > > > > (tested on 2.6.33.1 x86_64)
> > > > > 
> > > > > It's actually needed for mainline too (2.6.34-rc2).
> > > > 
> > > > Then all you need to do is submit it for mainline with a 
> > > > "Cc: stable@kernel.org" as you did below. It will then automatically be
> > > > added to the stable queue when Linus pulls it.
> > > 
> > > OK, thanks for the info.
> > 
> > And I need to wait until it goes into Linus's tree before it can be
> > applied to the stable tree.  This hasn't happened yet, right?
> > 
> > thanks,
> > 
> > greg k-h
> 
> Same here, for module.c fix. Feel free to choose between this fix or the
> corresponding refactoring from Tejun.

Thanks, I took this one.

greg k-h