[PATCH] memslot check before deferencing

[PATCH] memslot check before deferencing

[Nguyen Anh Quynh]

[-- Attachment #1: Type: text/plain, Size: 169 bytes --]

"memslot" in makr_page_dirty() should be verified before dereferencing
it (kvm_main.c)

Signed-off-by: Nguyen Anh Quynh <aquynh-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

[-- Attachment #2: patch9.patch --]
[-- Type: application/octet-stream, Size: 686 bytes --]

diff --git a/kernel/kvm_main.c b/kernel/kvm_main.c
index 84f95e4..da596fb 100644
--- a/kernel/kvm_main.c
+++ b/kernel/kvm_main.c
@@ -969,16 +969,16 @@ EXPORT_SYMBOL_GPL(gfn_to_page);
 void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
 {
 	int i;
-	struct kvm_memory_slot *memslot = NULL;
+	struct kvm_memory_slot *memslot;
 	unsigned long rel_gfn;
 
 	for (i = 0; i < kvm->nmemslots; ++i) {
 		memslot = &kvm->memslots[i];
 
-		if (gfn >= memslot->base_gfn
+		if (memslot && gfn >= memslot->base_gfn
 		    && gfn < memslot->base_gfn + memslot->npages) {
 
-			if (!memslot || !memslot->dirty_bitmap)
+			if (!memslot->dirty_bitmap)
 				return;
 
 			rel_gfn = gfn - memslot->base_gfn;

[-- Attachment #3: Type: text/plain, Size: 286 bytes --]

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Re: [PATCH] memslot check before deferencing

[Avi Kivity]

Nguyen Anh Quynh wrote:
> "memslot" in makr_page_dirty() should be verified before dereferencing
> it (kvm_main.c)

The patches still don't show up inlined.  This makes them hard to 
review.  Please fix this.

> diff --git a/kernel/kvm_main.c b/kernel/kvm_main.c
> index 84f95e4..da596fb 100644
> --- a/kernel/kvm_main.c
> +++ b/kernel/kvm_main.c
> @@ -969,16 +969,16 @@ EXPORT_SYMBOL_GPL(gfn_to_page);
>  void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
>  {
>      int i;
> -    struct kvm_memory_slot *memslot = NULL;
> +    struct kvm_memory_slot *memslot;
>      unsigned long rel_gfn;
>  
>      for (i = 0; i < kvm->nmemslots; ++i) {
>          memslot = &kvm->memslots[i];
>  
> -        if (gfn >= memslot->base_gfn
> +        if (memslot && gfn >= memslot->base_gfn

memslot can not be NULL here.

>              && gfn < memslot->base_gfn + memslot->npages) {
>  
> -            if (!memslot || !memslot->dirty_bitmap)

this is odd.

> +            if (!memslot->dirty_bitmap)
>                  return;
>  
>              rel_gfn = gfn - memslot->base_gfn;



-- 
error compiling committee.c: too many arguments to function


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Re: [PATCH] memslot check before deferencing

[Nguyen Anh Quynh]

[-- Attachment #1: Type: text/plain, Size: 1643 bytes --]

So take this patch instead. It remove the verification for NULL value
of memslot in mark_page_dirty().

I am trying to send patch in 2 format: .txt and .patch. If your mailer
cannot see them as inline text, I guess that is my gmail problem , and
there is nothing I can do.

So tell me if .txt patch is fine for you, or how do you want to take
patch from gmail.


On 6/4/07, Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org> wrote:
> Nguyen Anh Quynh wrote:
> > "memslot" in makr_page_dirty() should be verified before dereferencing
> > it (kvm_main.c)
>
> The patches still don't show up inlined.  This makes them hard to
> review.  Please fix this.
>
> > diff --git a/kernel/kvm_main.c b/kernel/kvm_main.c
> > index 84f95e4..da596fb 100644
> > --- a/kernel/kvm_main.c
> > +++ b/kernel/kvm_main.c
> > @@ -969,16 +969,16 @@ EXPORT_SYMBOL_GPL(gfn_to_page);
> >  void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
> >  {
> >      int i;
> > -    struct kvm_memory_slot *memslot = NULL;
> > +    struct kvm_memory_slot *memslot;
> >      unsigned long rel_gfn;
> >
> >      for (i = 0; i < kvm->nmemslots; ++i) {
> >          memslot = &kvm->memslots[i];
> >
> > -        if (gfn >= memslot->base_gfn
> > +        if (memslot && gfn >= memslot->base_gfn
>
> memslot can not be NULL here.
>
> >              && gfn < memslot->base_gfn + memslot->npages) {
> >
> > -            if (!memslot || !memslot->dirty_bitmap)
>
> this is odd.
>
> > +            if (!memslot->dirty_bitmap)
> >                  return;
> >
> >              rel_gfn = gfn - memslot->base_gfn;
>
>
>
> --
> error compiling committee.c: too many arguments to function
>
>

[-- Attachment #2: patch10.patch --]
[-- Type: text/x-patch, Size: 696 bytes --]

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 0e6d5d6..d5bb212 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -969,7 +969,7 @@ EXPORT_SYMBOL_GPL(gfn_to_page);
 void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
 {
 	int i;
-	struct kvm_memory_slot *memslot = NULL;
+	struct kvm_memory_slot *memslot;
 	unsigned long rel_gfn;
 
 	for (i = 0; i < kvm->nmemslots; ++i) {
@@ -978,7 +978,7 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
 		if (gfn >= memslot->base_gfn
 		    && gfn < memslot->base_gfn + memslot->npages) {
 
-			if (!memslot || !memslot->dirty_bitmap)
+			if (!memslot->dirty_bitmap)
 				return;
 
 			rel_gfn = gfn - memslot->base_gfn;

[-- Attachment #3: patch10.txt --]
[-- Type: text/plain, Size: 696 bytes --]

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 0e6d5d6..d5bb212 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -969,7 +969,7 @@ EXPORT_SYMBOL_GPL(gfn_to_page);
 void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
 {
 	int i;
-	struct kvm_memory_slot *memslot = NULL;
+	struct kvm_memory_slot *memslot;
 	unsigned long rel_gfn;
 
 	for (i = 0; i < kvm->nmemslots; ++i) {
@@ -978,7 +978,7 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
 		if (gfn >= memslot->base_gfn
 		    && gfn < memslot->base_gfn + memslot->npages) {
 
-			if (!memslot || !memslot->dirty_bitmap)
+			if (!memslot->dirty_bitmap)
 				return;
 
 			rel_gfn = gfn - memslot->base_gfn;

[-- Attachment #4: Type: text/plain, Size: 286 bytes --]

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Re: [PATCH] memslot check before deferencing

[Avi Kivity]

Nguyen Anh Quynh wrote:
> So take this patch instead. It remove the verification for NULL value
> of memslot in mark_page_dirty().
>

Applied, thanks.


> I am trying to send patch in 2 format: .txt and .patch. If your mailer
> cannot see them as inline text, I guess that is my gmail problem , and
> there is nothing I can do.

Well, now I see both of them inlined.

-- 
error compiling committee.c: too many arguments to function


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