[PATCH 1/6] arch/ia64/kernel: remove null pointer dereference

[PATCH 1/6] arch/ia64/kernel: remove null pointer dereference

[Julia Lawall]

From: Julia Lawall <julia@diku.dk>

If data is NULL, it is not possible to access data->ret.

The problem was detected using the following semantic match
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression E, E1;
identifier f;
statement S1,S2,S3;
@@

* if (E = NULL)
{
  ... when != if (E = NULL) S1 else S2
      when != E = E1
* E->f
  ... when any
  return ...;
}
else S3
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---

diff -u -p a/arch/ia64/kernel/palinfo.c b/arch/ia64/kernel/palinfo.c
--- a/arch/ia64/kernel/palinfo.c	2008-05-09 16:46:57.000000000 +0200
+++ b/arch/ia64/kernel/palinfo.c	2008-05-12 08:43:35.000000000 +0200
@@ -902,7 +902,6 @@ palinfo_smp_call(void *info)
 	palinfo_smp_data_t *data = (palinfo_smp_data_t *)info;
 	if (data = NULL) {
 		printk(KERN_ERR "palinfo: data pointer is NULL\n");
-		data->ret = 0; /* no output */
 		return;
 	}
 	/* does this actual call */

Re: [PATCH 1/6] arch/ia64/kernel: remove null pointer dereference

[Simon Holm Thøgersen]

man, 12 05 2008 kl. 15:37 +0200, skrev Julia Lawall:
> From: Julia Lawall <julia@diku.dk>
> 
> If data is NULL, it is not possible to access data->ret.
> 
> The problem was detected using the following semantic match
> (http://www.emn.fr/x-info/coccinelle/)
> 
> // <smpl>
> @@
> expression E, E1;
> identifier f;
> statement S1,S2,S3;
> @@
> 
> * if (E = NULL)
> {
>   ... when != if (E = NULL) S1 else S2
>       when != E = E1
> * E->f
>   ... when any
>   return ...;
> }
> else S3
> // </smpl>
> 
> Signed-off-by: Julia Lawall <julia@diku.dk>
> 
> ---
> 
> diff -u -p a/arch/ia64/kernel/palinfo.c b/arch/ia64/kernel/palinfo.c
> --- a/arch/ia64/kernel/palinfo.c	2008-05-09 16:46:57.000000000 +0200
> +++ b/arch/ia64/kernel/palinfo.c	2008-05-12 08:43:35.000000000 +0200
> @@ -902,7 +902,6 @@ palinfo_smp_call(void *info)
>  	palinfo_smp_data_t *data = (palinfo_smp_data_t *)info;
>  	if (data = NULL) {
>  		printk(KERN_ERR "palinfo: data pointer is NULL\n");
> -		data->ret = 0; /* no output */
>  		return;
>  	}
>  	/* does this actual call */
> --

The whole if block should just be deleted, as info is never NULL. There
is only palinfo_handle_smp as (indirect) user of palinfo_smp_call (by
way of smp_call_function_single) and surely palinfo_smp_call never pass
NULL.


Simon Holm Th√∏gersen

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Re: [PATCH 1/6] arch/ia64/kernel: remove null pointer dereference

[Julia Lawall]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 1504 bytes --]

On Mon, 12 May 2008, Simon Holm Thøgersen wrote:

> man, 12 05 2008 kl. 15:37 +0200, skrev Julia Lawall:
> > From: Julia Lawall <julia@diku.dk>
> > 
> > If data is NULL, it is not possible to access data->ret.
> > 
> > The problem was detected using the following semantic match
> > (http://www.emn.fr/x-info/coccinelle/)
> > 
> > // <smpl>
> > @@
> > expression E, E1;
> > identifier f;
> > statement S1,S2,S3;
> > @@
> > 
> > * if (E == NULL)
> > {
> >   ... when != if (E == NULL) S1 else S2
> >       when != E = E1
> > * E->f
> >   ... when any
> >   return ...;
> > }
> > else S3
> > // </smpl>
> > 
> > Signed-off-by: Julia Lawall <julia@diku.dk>
> > 
> > ---
> > 
> > diff -u -p a/arch/ia64/kernel/palinfo.c b/arch/ia64/kernel/palinfo.c
> > --- a/arch/ia64/kernel/palinfo.c	2008-05-09 16:46:57.000000000 +0200
> > +++ b/arch/ia64/kernel/palinfo.c	2008-05-12 08:43:35.000000000 +0200
> > @@ -902,7 +902,6 @@ palinfo_smp_call(void *info)
> >  	palinfo_smp_data_t *data = (palinfo_smp_data_t *)info;
> >  	if (data == NULL) {
> >  		printk(KERN_ERR "palinfo: data pointer is NULL\n");
> > -		data->ret = 0; /* no output */
> >  		return;
> >  	}
> >  	/* does this actual call */
> > --
> 
> The whole if block should just be deleted, as info is never NULL. There
> is only palinfo_handle_smp as (indirect) user of palinfo_smp_call (by
> way of smp_call_function_single) and surely palinfo_smp_call never pass
> NULL.

OK.  Will you fix it?

julia

[PATCH] Remove NULL pointer check for argument never passed as

[Simon Holm Thøgersen]

There is only palinfo_handle_smp as (indirect) user of palinfo_smp_call (by
way of smp_call_function_single) and surely palinfo_handle_smp never pass
NULL as parameter for info.

Signed-off-by: Simon Holm Th√∏gersen <odie@cs.aau.dk>
---
 arch/ia64/kernel/palinfo.c |    6 ------
 1 files changed, 0 insertions(+), 6 deletions(-)

diff --git a/arch/ia64/kernel/palinfo.c b/arch/ia64/kernel/palinfo.c
index 4547a20..9dc00f7 100644
--- a/arch/ia64/kernel/palinfo.c
+++ b/arch/ia64/kernel/palinfo.c
@@ -900,12 +900,6 @@ static void
 palinfo_smp_call(void *info)
 {
 	palinfo_smp_data_t *data = (palinfo_smp_data_t *)info;
-	if (data = NULL) {
-		printk(KERN_ERR "palinfo: data pointer is NULL\n");
-		data->ret = 0; /* no output */
-		return;
-	}
-	/* does this actual call */
 	data->ret = (*data->func)(data->page);
 }
 
-- 
1.5.5.1.125.gc697a

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