[PATCH linux-next v3] mlx5: wrong page mask if CONFIG_ARCH_DMA_ADDR_T_64BIT enabled for 32Bit architectures

[PATCH linux-next v3] mlx5: wrong page mask if CONFIG_ARCH_DMA_ADDR_T_64BIT enabled for 32Bit architectures

[Honggang Li]

If CONFIG_ARCH_DMA_ADDR_T_64BIT enabled for x86 systems and physical
memory is more than 4GB, dma_map_page may return a valid memory
address which greater than 0xffffffff. As a result, the mlx5 device page
allocator RB tree will be initialized with valid addresses greater than
0xfffffff.

However, (addr & PAGE_MASK) set the high four bytes to zeros. So, it's
impossible for the function, free_4k, to release the pages whose
addresses greater than 4GB. Memory leaks. And mlx5_ib module can't
release the pages when user try to remove the module, as a result,
system hang.

[root@rdma05 root]# dmesg  | grep addr | head
addr             = 3fe384000
addr & PAGE_MASK =  fe384000
[root@rdma05 root]# rmmod mlx5_ib   <---- hang on

---------------------- cosnole log -----------------
mlx5_ib 0000:04:00.0: irq 138 for MSI/MSI-X
  alloc irq_desc for 139 on node -1
  alloc kstat_irqs on node -1
mlx5_ib 0000:04:00.0: irq 139 for MSI/MSI-X
0000:04:00.0:free_4k:221:(pid 1519): page not found
0000:04:00.0:free_4k:221:(pid 1519): page not found
0000:04:00.0:free_4k:221:(pid 1519): page not found
0000:04:00.0:free_4k:221:(pid 1519): page not found
---------------------- cosnole log -----------------

Fix(bf0bf77 mlx5: Support communicating arbitrary host page size to
firmware)

Signed-off-by: Honggang Li <honli-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 .../net/ethernet/mellanox/mlx5/core/pagealloc.c    |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c b/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
index df22383..8a64542 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
@@ -211,26 +211,28 @@ static int alloc_4k(struct mlx5_core_dev *dev, u64 *addr)
 	return 0;
 }
 
+#define MLX5_U64_4K_PAGE_MASK ((~(u64)0U) << PAGE_SHIFT)
+
 static void free_4k(struct mlx5_core_dev *dev, u64 addr)
 {
 	struct fw_page *fwp;
 	int n;
 
-	fwp = find_fw_page(dev, addr & PAGE_MASK);
+	fwp = find_fw_page(dev, addr & MLX5_U64_4K_PAGE_MASK);
 	if (!fwp) {
 		mlx5_core_warn(dev, "page not found\n");
 		return;
 	}
 
-	n = (addr & ~PAGE_MASK) >> MLX5_ADAPTER_PAGE_SHIFT;
+	n = (addr & ~MLX5_U64_4K_PAGE_MASK) >> MLX5_ADAPTER_PAGE_SHIFT;
 	fwp->free_count++;
 	set_bit(n, &fwp->bitmask);
 	if (fwp->free_count == MLX5_NUM_4K_IN_PAGE) {
 		rb_erase(&fwp->rb_node, &dev->priv.page_root);
 		if (fwp->free_count != 1)
 			list_del(&fwp->list);
-		dma_unmap_page(&dev->pdev->dev, addr & PAGE_MASK, PAGE_SIZE,
-			       DMA_BIDIRECTIONAL);
+		dma_unmap_page(&dev->pdev->dev, addr & MLX5_U64_4K_PAGE_MASK,
+			       PAGE_SIZE, DMA_BIDIRECTIONAL);
 		__free_page(fwp->page);
 		kfree(fwp);
 	} else if (fwp->free_count == 1) {
-- 
1.7.1

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Re: [PATCH linux-next v3] mlx5: wrong page mask if CONFIG_ARCH_DMA_ADDR_T_64BIT enabled for 32Bit architectures

[Eli Cohen]

Acked-by: Eli Cohen <eli-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

On Wed, Apr 15, 2015 at 11:19:17AM +0800, Honggang Li wrote:
> If CONFIG_ARCH_DMA_ADDR_T_64BIT enabled for x86 systems and physical
> memory is more than 4GB, dma_map_page may return a valid memory
> address which greater than 0xffffffff. As a result, the mlx5 device page
> allocator RB tree will be initialized with valid addresses greater than
> 0xfffffff.
> 
> However, (addr & PAGE_MASK) set the high four bytes to zeros. So, it's
> impossible for the function, free_4k, to release the pages whose
> addresses greater than 4GB. Memory leaks. And mlx5_ib module can't
> release the pages when user try to remove the module, as a result,
> system hang.
> 
> [root@rdma05 root]# dmesg  | grep addr | head
> addr             = 3fe384000
> addr & PAGE_MASK =  fe384000
> [root@rdma05 root]# rmmod mlx5_ib   <---- hang on
> 
> ---------------------- cosnole log -----------------
> mlx5_ib 0000:04:00.0: irq 138 for MSI/MSI-X
>   alloc irq_desc for 139 on node -1
>   alloc kstat_irqs on node -1
> mlx5_ib 0000:04:00.0: irq 139 for MSI/MSI-X
> 0000:04:00.0:free_4k:221:(pid 1519): page not found
> 0000:04:00.0:free_4k:221:(pid 1519): page not found
> 0000:04:00.0:free_4k:221:(pid 1519): page not found
> 0000:04:00.0:free_4k:221:(pid 1519): page not found
> ---------------------- cosnole log -----------------
> 
> Fix(bf0bf77 mlx5: Support communicating arbitrary host page size to
> firmware)
> 
> Signed-off-by: Honggang Li <honli-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  .../net/ethernet/mellanox/mlx5/core/pagealloc.c    |   10 ++++++----
>  1 files changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c b/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
> index df22383..8a64542 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
> @@ -211,26 +211,28 @@ static int alloc_4k(struct mlx5_core_dev *dev, u64 *addr)
>  	return 0;
>  }
>  
> +#define MLX5_U64_4K_PAGE_MASK ((~(u64)0U) << PAGE_SHIFT)
> +
>  static void free_4k(struct mlx5_core_dev *dev, u64 addr)
>  {
>  	struct fw_page *fwp;
>  	int n;
>  
> -	fwp = find_fw_page(dev, addr & PAGE_MASK);
> +	fwp = find_fw_page(dev, addr & MLX5_U64_4K_PAGE_MASK);
>  	if (!fwp) {
>  		mlx5_core_warn(dev, "page not found\n");
>  		return;
>  	}
>  
> -	n = (addr & ~PAGE_MASK) >> MLX5_ADAPTER_PAGE_SHIFT;
> +	n = (addr & ~MLX5_U64_4K_PAGE_MASK) >> MLX5_ADAPTER_PAGE_SHIFT;
>  	fwp->free_count++;
>  	set_bit(n, &fwp->bitmask);
>  	if (fwp->free_count == MLX5_NUM_4K_IN_PAGE) {
>  		rb_erase(&fwp->rb_node, &dev->priv.page_root);
>  		if (fwp->free_count != 1)
>  			list_del(&fwp->list);
> -		dma_unmap_page(&dev->pdev->dev, addr & PAGE_MASK, PAGE_SIZE,
> -			       DMA_BIDIRECTIONAL);
> +		dma_unmap_page(&dev->pdev->dev, addr & MLX5_U64_4K_PAGE_MASK,
> +			       PAGE_SIZE, DMA_BIDIRECTIONAL);
>  		__free_page(fwp->page);
>  		kfree(fwp);
>  	} else if (fwp->free_count == 1) {
> -- 
> 1.7.1
> 
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Re: [PATCH linux-next v3] mlx5: wrong page mask if CONFIG_ARCH_DMA_ADDR_T_64BIT enabled for 32Bit architectures

[Or Gerlitz]

On 4/15/2015 6:19 AM, Honggang Li wrote:
> Fix(bf0bf77 mlx5: Support communicating arbitrary host page size to firmware)

This isn't the way to write the fix note, do it that way

Fixes: bf0bf77f6519 ('mlx5: Support communicating arbitrary host page 
size to firmware')

>
> Signed-off-by: Honggang Li<honli-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

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Re: [PATCH linux-next v3] mlx5: wrong page mask if CONFIG_ARCH_DMA_ADDR_T_64BIT enabled for 32Bit architectures

[Honggang LI]

On Wed, Apr 15, 2015 at 08:27:23AM +0300, Or Gerlitz wrote:
> On 4/15/2015 6:19 AM, Honggang Li wrote:
> >Fix(bf0bf77 mlx5: Support communicating arbitrary host page size to firmware)
> 
> This isn't the way to write the fix note, do it that way
> 
> Fixes: bf0bf77f6519 ('mlx5: Support communicating arbitrary host
> page size to firmware')
> 

Fixed it and new patch (v4) had been sent out. Please review it. Hope it
is the final one.

thanks

> >
> >Signed-off-by: Honggang Li<honli@redhat.com>
>