[PATCH] Use the tsk argument in init_new_context()

[PATCH] Use the tsk argument in init_new_context()

[Diego Woitasen]

Signed-off-by: Diego Woitasen <diego@woitasen.com.ar>
---
 arch/i386/kernel/ldt.c   |    2 +-
 arch/x86_64/kernel/ldt.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/i386/kernel/ldt.c b/arch/i386/kernel/ldt.c
index e0b2d17..c2eb4fb 100644
--- a/arch/i386/kernel/ldt.c
+++ b/arch/i386/kernel/ldt.c
@@ -96,7 +96,7 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 
 	init_MUTEX(&mm->context.sem);
 	mm->context.size = 0;
-	old_mm = current->mm;
+	old_mm = tsk->mm;
 	if (old_mm && old_mm->context.size > 0) {
 		down(&old_mm->context.sem);
 		retval = copy_ldt(&mm->context, &old_mm->context);
diff --git a/arch/x86_64/kernel/ldt.c b/arch/x86_64/kernel/ldt.c
index bc9ffd5..99a92ed 100644
--- a/arch/x86_64/kernel/ldt.c
+++ b/arch/x86_64/kernel/ldt.c
@@ -100,7 +100,7 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 
 	init_MUTEX(&mm->context.sem);
 	mm->context.size = 0;
-	old_mm = current->mm;
+	old_mm = tsk->mm;
 	if (old_mm && old_mm->context.size > 0) {
 		down(&old_mm->context.sem);
 		retval = copy_ldt(&mm->context, &old_mm->context);
-- 
1.5.2.3

Re: [PATCH] Use the tsk argument in init_new_context()

[Andrew Morton]

On Sun,  8 Jul 2007 22:55:08 -0300
Diego Woitasen <diego@woitasen.com.ar> wrote:

> Signed-off-by: Diego Woitasen <diego@woitasen.com.ar>
> ---
>  arch/i386/kernel/ldt.c   |    2 +-
>  arch/x86_64/kernel/ldt.c |    2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/i386/kernel/ldt.c b/arch/i386/kernel/ldt.c
> index e0b2d17..c2eb4fb 100644
> --- a/arch/i386/kernel/ldt.c
> +++ b/arch/i386/kernel/ldt.c
> @@ -96,7 +96,7 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
>  
>  	init_MUTEX(&mm->context.sem);
>  	mm->context.size = 0;
> -	old_mm = current->mm;
> +	old_mm = tsk->mm;
>  	if (old_mm && old_mm->context.size > 0) {
>  		down(&old_mm->context.sem);
>  		retval = copy_ldt(&mm->context, &old_mm->context);
> diff --git a/arch/x86_64/kernel/ldt.c b/arch/x86_64/kernel/ldt.c
> index bc9ffd5..99a92ed 100644
> --- a/arch/x86_64/kernel/ldt.c
> +++ b/arch/x86_64/kernel/ldt.c
> @@ -100,7 +100,7 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
>  
>  	init_MUTEX(&mm->context.sem);
>  	mm->context.size = 0;
> -	old_mm = current->mm;
> +	old_mm = tsk->mm;
>  	if (old_mm && old_mm->context.size > 0) {
>  		down(&old_mm->context.sem);
>  		retval = copy_ldt(&mm->context, &old_mm->context);


When called from dup_mm(), `tsk' refers to the new task and `current'
refers to the old one.  I'd have expected this to crash during your testing?

Re: [PATCH] Use the tsk argument in init_new_context()

[Diego Woitasen]

On Thu, Jul 19, 2007 at 05:42:38PM -0700, Andrew Morton wrote:
> On Sun,  8 Jul 2007 22:55:08 -0300
> Diego Woitasen <diego@woitasen.com.ar> wrote:
> 
> > Signed-off-by: Diego Woitasen <diego@woitasen.com.ar>
> > ---
> >  arch/i386/kernel/ldt.c   |    2 +-
> >  arch/x86_64/kernel/ldt.c |    2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/i386/kernel/ldt.c b/arch/i386/kernel/ldt.c
> > index e0b2d17..c2eb4fb 100644
> > --- a/arch/i386/kernel/ldt.c
> > +++ b/arch/i386/kernel/ldt.c
> > @@ -96,7 +96,7 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
> >  
> >  	init_MUTEX(&mm->context.sem);
> >  	mm->context.size = 0;
> > -	old_mm = current->mm;
> > +	old_mm = tsk->mm;
> >  	if (old_mm && old_mm->context.size > 0) {
> >  		down(&old_mm->context.sem);
> >  		retval = copy_ldt(&mm->context, &old_mm->context);
> > diff --git a/arch/x86_64/kernel/ldt.c b/arch/x86_64/kernel/ldt.c
> > index bc9ffd5..99a92ed 100644
> > --- a/arch/x86_64/kernel/ldt.c
> > +++ b/arch/x86_64/kernel/ldt.c
> > @@ -100,7 +100,7 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
> >  
> >  	init_MUTEX(&mm->context.sem);
> >  	mm->context.size = 0;
> > -	old_mm = current->mm;
> > +	old_mm = tsk->mm;
> >  	if (old_mm && old_mm->context.size > 0) {
> >  		down(&old_mm->context.sem);
> >  		retval = copy_ldt(&mm->context, &old_mm->context);
> 
> 
> When called from dup_mm(), `tsk' refers to the new task and `current'
> refers to the old one.  I'd have expected this to crash during your testing?
> -
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Yes, sorry... that patch is bad. Now my question is, why all
architectures have the task argument and neither use it? I undertand now
that init_new_context() work with current but what about the *tsk arg.



-- 

--------------
Diego Woitasen