diff mbox

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

Message ID DB4PR05MB4487E0A2EDB25BF090A9742C5F80@DB4PR05MB448.eurprd05.prod.outlook.com
State RFC, archived
Delegated to: David Miller
Headers show

Commit Message

Eli Cohen April 12, 2015, 3:04 p.m. UTC 
Good catch, thanks!

There are more places in this file where PAGE_MASK is wrongly used. Need to fix them as well.

Also, see below [Eli]



-----Original Message-----
From: Honggang Li [mailto:honli@redhat.com] 
Sent: Sunday, April 12, 2015 2:06 PM
To: Eli Cohen; netdev@vger.kernel.org; linux-rdma@vger.kernel.org; linux-kernel@vger.kernel.org
Cc: Honggang Li
Subject: [linux-next PATCH] mlx5: wrong page mask if CONFIG_ARCH_DMA_ADDR_T_64BIT enabled for 32Bit architectures

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 -----------------

Signed-off-by: Honggang Li <honli@redhat.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

 	struct page *page;
-	u64 addr;
+	u64 addr = 0; [Eli] Why is this required?
 	int err;
 	int nid = dev_to_node(&dev->pdev->dev);
 
--
1.8.3.1

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c b/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
index df22383..27c72da 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c
@@ -211,12 +211,14 @@  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;
@@ -241,7 +243,7 @@  static void free_4k(struct mlx5_core_dev *dev, u64 addr)  static int alloc_system_page(struct mlx5_core_dev *dev, u16 func_id)  {