2018-02-22 11:23:50

by Miles Chen

Subject: [PATCH] lib/dma-debug.c: fix memory leakage

From: Miles Chen <[email protected]>

Marty reported a memory leakage introduced by commit 3aaabbf1c39e
("lib/dma-debug.c: fix incorrect pfn calculation"). Fix it
by checking the virtual address before allocating the entry.

This patch also use virt_addr_valid() instead of virt_to_page()
to check if a virtual address is linear.

Reported-by: Marty Faltesek <[email protected]>
Signed-off-by: Miles Chen <[email protected]>
---
lib/dma-debug.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 1b34d210452c..7f5cdc1e6b29 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -1491,12 +1491,12 @@ void debug_dma_alloc_coherent(struct device *dev, size_t size,
if (unlikely(virt == NULL))
return;

- entry = dma_entry_alloc();
- if (!entry)
+ /* handle vmalloc and linear addresses */
+ if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
return;

- /* handle vmalloc and linear addresses */
- if (!is_vmalloc_addr(virt) && !virt_to_page(virt))
+ entry = dma_entry_alloc();
+ if (!entry)
return;

entry->type = dma_debug_coherent;
@@ -1528,7 +1528,7 @@ void debug_dma_free_coherent(struct device *dev, size_t size,
};

/* handle vmalloc and linear addresses */
- if (!is_vmalloc_addr(virt) && !virt_to_page(virt))
+ if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
return;

if (is_vmalloc_addr(virt))
--
2.12.5

2018-02-22 14:05:56

by Robin Murphy

Subject: Re: [PATCH] lib/dma-debug.c: fix memory leakage

On 22/02/18 11:22, [email protected] wrote:
> From: Miles Chen <[email protected]>
>
> Marty reported a memory leakage introduced by commit 3aaabbf1c39e
> ("lib/dma-debug.c: fix incorrect pfn calculation"). Fix it
> by checking the virtual address before allocating the entry.

Oops, seems I failed to look closely enough at the surrounding diff
context when I reviewed the original patch... :(

> This patch also use virt_addr_valid() instead of virt_to_page()
> to check if a virtual address is linear.

That's an area I happen to have been looking at lately and now
understand a lot better, so fully agreed there as well.

Acked-by: Robin Murphy <[email protected]>

Maybe also worth having a proper Fixes: tag instead of just naming the
commit in prose?

Thanks,
Robin.

> Reported-by: Marty Faltesek <[email protected]>
> Signed-off-by: Miles Chen <[email protected]>
> ---
> lib/dma-debug.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/lib/dma-debug.c b/lib/dma-debug.c
> index 1b34d210452c..7f5cdc1e6b29 100644
> --- a/lib/dma-debug.c
> +++ b/lib/dma-debug.c
> @@ -1491,12 +1491,12 @@ void debug_dma_alloc_coherent(struct device *dev, size_t size,
> if (unlikely(virt == NULL))
> return;
>
> - entry = dma_entry_alloc();
> - if (!entry)
> + /* handle vmalloc and linear addresses */
> + if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
> return;
>
> - /* handle vmalloc and linear addresses */
> - if (!is_vmalloc_addr(virt) && !virt_to_page(virt))
> + entry = dma_entry_alloc();
> + if (!entry)
> return;
>
> entry->type = dma_debug_coherent;
> @@ -1528,7 +1528,7 @@ void debug_dma_free_coherent(struct device *dev, size_t size,
> };
>
> /* handle vmalloc and linear addresses */
> - if (!is_vmalloc_addr(virt) && !virt_to_page(virt))
> + if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
> return;
>
> if (is_vmalloc_addr(virt))
>

2018-02-22 23:05:13

by Christoph Hellwig

Subject: Re: [PATCH] lib/dma-debug.c: fix memory leakage

Thanks, applied to the dma mapping tree for 4.16, including the Fixes
tag.