[PATCH -mm] bugfix: pass aggr_kprobe to arch_remove_kprobe

[PATCH -mm] bugfix: pass aggr_kprobe to arch_remove_kprobe

[Masami Hiramatsu]

Hi Andrew,

akpm@linux-foundation.org wrote:
> The patch titled
>      kprobes: support probing module __exit function
> has been added to the -mm tree.  Its filename is
>      kprobes-support-probing-module-__exit-function.patch

I found that one bug was still alive. Here is the bugfix.

Thank you,

Call arch_remove_kprobe() with aggr_kprobe instead of user specific kprobe,
because the user specific kprobe on the gone or reused aggr_kprobe may have
invalid arch_specific_insn.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
---
 kernel/kprobes.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

Index: 2.6-rc/kernel/kprobes.c
===================================================================
--- 2.6-rc.orig/kernel/kprobes.c
+++ 2.6-rc/kernel/kprobes.c
@@ -766,14 +766,14 @@ static void __kprobes __unregister_kprob
 {
 	struct kprobe *old_p;

-	if (list_empty(&p->list) || list_is_singular(&p->list)) {
-		if (!list_empty(&p->list)) {
-			/* "p" is the last child of an aggr_kprobe */
-			old_p = list_entry(p->list.next, struct kprobe, list);
-			list_del(&p->list);
-			kfree(old_p);
-		}
+	if (list_empty(&p->list))
 		arch_remove_kprobe(p);
+	else if (list_is_singular(&p->list)) {
+		/* "p" is the last child of an aggr_kprobe */
+		old_p = list_entry(p->list.next, struct kprobe, list);
+		list_del(&p->list);
+		arch_remove_kprobe(old_p);
+		kfree(old_p);
 	}
 }


-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com

Re: [PATCH -mm] bugfix: pass aggr_kprobe to arch_remove_kprobe

[Ananth N Mavinakayanahalli]

On Tue, Nov 18, 2008 at 11:29:01AM -0500, Masami Hiramatsu wrote:
> Hi Andrew,
> 
> akpm@linux-foundation.org wrote:
> > The patch titled
> >      kprobes: support probing module __exit function
> > has been added to the -mm tree.  Its filename is
> >      kprobes-support-probing-module-__exit-function.patch
> 
> I found that one bug was still alive. Here is the bugfix.
> 
> Thank you,
> 
> Call arch_remove_kprobe() with aggr_kprobe instead of user specific kprobe,
> because the user specific kprobe on the gone or reused aggr_kprobe may have
> invalid arch_specific_insn.
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>

Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>

> ---
>  kernel/kprobes.c |   14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> Index: 2.6-rc/kernel/kprobes.c
> ===================================================================
> --- 2.6-rc.orig/kernel/kprobes.c
> +++ 2.6-rc/kernel/kprobes.c
> @@ -766,14 +766,14 @@ static void __kprobes __unregister_kprob
>  {
>  	struct kprobe *old_p;
> 
> -	if (list_empty(&p->list) || list_is_singular(&p->list)) {
> -		if (!list_empty(&p->list)) {
> -			/* "p" is the last child of an aggr_kprobe */
> -			old_p = list_entry(p->list.next, struct kprobe, list);
> -			list_del(&p->list);
> -			kfree(old_p);
> -		}
> +	if (list_empty(&p->list))
>  		arch_remove_kprobe(p);
> +	else if (list_is_singular(&p->list)) {
> +		/* "p" is the last child of an aggr_kprobe */
> +		old_p = list_entry(p->list.next, struct kprobe, list);
> +		list_del(&p->list);
> +		arch_remove_kprobe(old_p);
> +		kfree(old_p);
>  	}
>  }
> 
> 
> -- 
> Masami Hiramatsu
> 
> Software Engineer
> Hitachi Computer Products (America) Inc.
> Software Solutions Division
> 
> e-mail: mhiramat@redhat.com
>