Patch "net/mlx5e: Fix dangling page pointer on DMA mapping error" has been added to the 4.12-stable tree

Patch "net/mlx5e: Fix dangling page pointer on DMA mapping error" has been added to the 4.12-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    net/mlx5e: Fix dangling page pointer on DMA mapping error

to the 4.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-mlx5e-fix-dangling-page-pointer-on-dma-mapping-error.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Thu Sep 14 23:20:23 PDT 2017
From: Eran Ben Elisha <eranbe@mellanox.com>
Date: Wed, 16 Aug 2017 14:37:11 +0300
Subject: net/mlx5e: Fix dangling page pointer on DMA mapping error

From: Eran Ben Elisha <eranbe@mellanox.com>


[ Upstream commit 0556ce72ab16156af6c94cdc7964e4310acc97c0 ]

Function mlx5e_dealloc_rx_wqe is using page pointer value as an
indication to valid DMA mapping. In case that the mapping failed, we
released the page but kept the dangling pointer. Store the page pointer
only after the DMA mapping passed to avoid invalid page DMA unmap.

Fixes: bc77b240b3c5 ("net/mlx5e: Add fragmented memory support for RX multi packet WQE")
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_rx.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -216,13 +216,13 @@ static inline int mlx5e_page_alloc_mappe
 	if (unlikely(!page))
 		return -ENOMEM;
 
-	dma_info->page = page;
 	dma_info->addr = dma_map_page(rq->pdev, page, 0,
 				      RQ_PAGE_SIZE(rq), rq->buff.map_dir);
 	if (unlikely(dma_mapping_error(rq->pdev, dma_info->addr))) {
 		put_page(page);
 		return -ENOMEM;
 	}
+	dma_info->page = page;
 
 	return 0;
 }


Patches currently in stable-queue which might be from eranbe@mellanox.com are

queue-4.12/net-mlx5e-fix-dangling-page-pointer-on-dma-mapping-error.patch