Messages in this thread Patches in this message | | | Date | Mon, 13 Apr 2015 08:33:33 +0800 | From | Honggang LI <> | Subject | Re: [linux-next PATCH] mlx5: wrong page mask if CONFIG_ARCH_DMA_ADDR_T_64BIT enabled for 32Bit architectures |
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On Sun, Apr 12, 2015 at 03:04:16PM +0000, Eli Cohen wrote: > Good catch, thanks! > > There are more places in this file where PAGE_MASK is wrongly used. Need to fix them as well. >
Yes, replaced all of the PAGE_MASK in the file. Please see attched new patch.
> Also, see below [Eli] > > @@ -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) { > struct page *page; > - u64 addr; > + u64 addr = 0; [Eli] Why is this required?
For 32bit architectures, if CONFIG_ARCH_DMA_ADDR_T_64BIT disabled and physical memory is less than 4GB, dma_map_page will return an u32 integer less than 0xffff_ffff. And if addr had been initialized with random rubbish in the stack of alloc_system_page, the high four bytes is unpredictable. The new mask, MLX5_NUM_4K_IN_PAGE, will reserve the high four bytes. So, free_4k/find_fw_page will randomly failed.
thanks
> int err; > int nid = dev_to_node(&dev->pdev->dev); > > -- > 1.8.3.1 > From 393cfb80c10e8e3a89baf7d235dde7aa3c64837d Mon Sep 17 00:00:00 2001 From: Honggang Li <honli@redhat.com> Date: Mon, 13 Apr 2015 08:10:10 +0800 Subject: [PATCH linux-next v2] 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 | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c b/drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c index df22383..595b507 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) { @@ -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) { struct page *page; - u64 addr; + u64 addr = 0; int err; int nid = dev_to_node(&dev->pdev->dev); -- 1.8.3.1
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