diff mbox

[RFC,v3,6/6] fix wrong get_user_pages usage in iovlock.c

Message ID 20090414152151.C659.A69D9226@jp.fujitsu.com
State RFC, archived
Delegated to: David Miller
Headers show

Commit Message

KOSAKI Motohiro April 14, 2009, 6:23 a.m. UTC 
I don't have NET-DMA usable device. I hope to get expert review.



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Comments

Nick Piggin April 14, 2009, 6:56 a.m. UTC | #1 
On Tuesday 14 April 2009 16:23:13 KOSAKI Motohiro wrote:
> I don't have NET-DMA usable device. I hope to get expert review.
> 
> =========================
> Subject: [Untested][RFC][PATCH] fix wrong get_user_pages usage in iovlock.c
> 
> 	down_read(mmap_sem)
> 	get_user_pages()
> 	up_read(mmap_sem)
> 
> is fork unsafe.
> fix it.
> 
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
> Cc: Maciej Sosnowski <maciej.sosnowski@intel.com>
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Chris Leech <christopher.leech@intel.com>
> Cc: netdev@vger.kernel.org
> ---
>  drivers/dma/iovlock.c |   18 ++++++------------
>  1 file changed, 6 insertions(+), 12 deletions(-)
> 
> Index: b/drivers/dma/iovlock.c
> ===================================================================
> --- a/drivers/dma/iovlock.c	2009-02-21 16:53:23.000000000 +0900
> +++ b/drivers/dma/iovlock.c	2009-04-13 04:46:02.000000000 +0900
> @@ -94,18 +94,10 @@ struct dma_pinned_list *dma_pin_iovec_pa
>  		pages += page_list->nr_pages;
>  
>  		/* pin pages down */
> -		down_read(&current->mm->mmap_sem);
> -		ret = get_user_pages(
> -			current,
> -			current->mm,
> -			(unsigned long) iov[i].iov_base,
> -			page_list->nr_pages,
> -			1,	/* write */
> -			0,	/* force */
> -			page_list->pages,
> -			NULL);
> -		up_read(&current->mm->mmap_sem);
> -
> +		down_read(&current->mm->mm_pinned_sem);
> +		ret = get_user_pages_fast((unsigned long) iov[i].iov_base,
> +					  page_list->nr_pages, 1,
> +					  page_list->pages);

I would perhaps not fold gup_fast conversions into the same patch as
the fix.


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KOSAKI Motohiro April 14, 2009, 6:58 a.m. UTC | #2 
> On Tuesday 14 April 2009 16:23:13 KOSAKI Motohiro wrote:
> > I don't have NET-DMA usable device. I hope to get expert review.
> > 
> > =========================
> > Subject: [Untested][RFC][PATCH] fix wrong get_user_pages usage in iovlock.c
> > 
> > 	down_read(mmap_sem)
> > 	get_user_pages()
> > 	up_read(mmap_sem)
> > 
> > is fork unsafe.
> > fix it.
> > 
> > Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
> > Cc: Maciej Sosnowski <maciej.sosnowski@intel.com>
> > Cc: David S. Miller <davem@davemloft.net>
> > Cc: Chris Leech <christopher.leech@intel.com>
> > Cc: netdev@vger.kernel.org
> > ---
> >  drivers/dma/iovlock.c |   18 ++++++------------
> >  1 file changed, 6 insertions(+), 12 deletions(-)
> > 
> > Index: b/drivers/dma/iovlock.c
> > ===================================================================
> > --- a/drivers/dma/iovlock.c	2009-02-21 16:53:23.000000000 +0900
> > +++ b/drivers/dma/iovlock.c	2009-04-13 04:46:02.000000000 +0900
> > @@ -94,18 +94,10 @@ struct dma_pinned_list *dma_pin_iovec_pa
> >  		pages += page_list->nr_pages;
> >  
> >  		/* pin pages down */
> > -		down_read(&current->mm->mmap_sem);
> > -		ret = get_user_pages(
> > -			current,
> > -			current->mm,
> > -			(unsigned long) iov[i].iov_base,
> > -			page_list->nr_pages,
> > -			1,	/* write */
> > -			0,	/* force */
> > -			page_list->pages,
> > -			NULL);
> > -		up_read(&current->mm->mmap_sem);
> > -
> > +		down_read(&current->mm->mm_pinned_sem);
> > +		ret = get_user_pages_fast((unsigned long) iov[i].iov_base,
> > +					  page_list->nr_pages, 1,
> > +					  page_list->pages);
> 
> I would perhaps not fold gup_fast conversions into the same patch as
> the fix.

OK. I'll fix.


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diff mbox

Patch

=========================
Subject: [Untested][RFC][PATCH] fix wrong get_user_pages usage in iovlock.c

	down_read(mmap_sem)
	get_user_pages()
	up_read(mmap_sem)

is fork unsafe.
fix it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Maciej Sosnowski <maciej.sosnowski@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Chris Leech <christopher.leech@intel.com>
Cc: netdev@vger.kernel.org
---
 drivers/dma/iovlock.c |   18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

Index: b/drivers/dma/iovlock.c
===================================================================
--- a/drivers/dma/iovlock.c	2009-02-21 16:53:23.000000000 +0900
+++ b/drivers/dma/iovlock.c	2009-04-13 04:46:02.000000000 +0900
@@ -94,18 +94,10 @@  struct dma_pinned_list *dma_pin_iovec_pa
 		pages += page_list->nr_pages;
 
 		/* pin pages down */
-		down_read(&current->mm->mmap_sem);
-		ret = get_user_pages(
-			current,
-			current->mm,
-			(unsigned long) iov[i].iov_base,
-			page_list->nr_pages,
-			1,	/* write */
-			0,	/* force */
-			page_list->pages,
-			NULL);
-		up_read(&current->mm->mmap_sem);
-
+		down_read(&current->mm->mm_pinned_sem);
+		ret = get_user_pages_fast((unsigned long) iov[i].iov_base,
+					  page_list->nr_pages, 1,
+					  page_list->pages);
 		if (ret != page_list->nr_pages)
 			goto unpin;
 
@@ -127,6 +119,8 @@  void dma_unpin_iovec_pages(struct dma_pi
 	if (!pinned_list)
 		return;
 
+	up_read(&current->mm->mm_pinned_sem);
+
 	for (i = 0; i < pinned_list->nr_iovecs; i++) {
 		struct dma_page_list *page_list = &pinned_list->page_list[i];
 		for (j = 0; j < page_list->nr_pages; j++) {