* [PATCH] dma-debug: Avoid NULL dereference when checking sync
@ 2016-10-31 15:11 Maarten ter Huurne
2016-11-08 0:38 ` Andrew Morton
0 siblings, 1 reply; 3+ messages in thread
From: Maarten ter Huurne @ 2016-10-31 15:11 UTC (permalink / raw)
To: Vinod Koul; +Cc: Andrew Morton, dmaengine, linux-kernel, Maarten ter Huurne
check_sync() calls bucket_find_contain(), which in turn calls
dma_get_max_seg_size(), which dereferences the device pointer.
Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
---
lib/dma-debug.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 8971370..84c6e88 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -1223,6 +1223,11 @@ static void check_sync(struct device *dev,
struct hash_bucket *bucket;
unsigned long flags;
+ if (!ref->dev) {
+ err_printk(dev, NULL, "DMA-API: device driver passes NULL for device to DMA sync function; cannot check usage\n");
+ return;
+ }
+
bucket = get_hash_bucket(ref, &flags);
entry = bucket_find_contain(&bucket, ref, &flags);
--
2.6.6
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] dma-debug: Avoid NULL dereference when checking sync
2016-10-31 15:11 [PATCH] dma-debug: Avoid NULL dereference when checking sync Maarten ter Huurne
@ 2016-11-08 0:38 ` Andrew Morton
0 siblings, 0 replies; 3+ messages in thread
From: Andrew Morton @ 2016-11-08 0:38 UTC (permalink / raw)
To: Maarten ter Huurne; +Cc: Vinod Koul, dmaengine, linux-kernel
On Mon, 31 Oct 2016 16:11:41 +0100 Maarten ter Huurne <maarten@treewalker.org> wrote:
> check_sync() calls bucket_find_contain(), which in turn calls
> dma_get_max_seg_size(), which dereferences the device pointer.
>
> ...
>
> --- a/lib/dma-debug.c
> +++ b/lib/dma-debug.c
> @@ -1223,6 +1223,11 @@ static void check_sync(struct device *dev,
> struct hash_bucket *bucket;
> unsigned long flags;
>
> + if (!ref->dev) {
> + err_printk(dev, NULL, "DMA-API: device driver passes NULL for device to DMA sync function; cannot check usage\n");
> + return;
> + }
> +
> bucket = get_hash_bucket(ref, &flags);
>
> entry = bucket_find_contain(&bucket, ref, &flags);
Well.
a) who is calling check_sync() without having filled in ref.dev?
How does this occur? Is this a bug in the caller?
b) why does check_sync() have a `dev' argument anyway? Is there any
situation in which that will differ from ref.dev?
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] dma-debug: Avoid NULL dereference when checking sync
@ 2016-02-28 15:20 Maarten ter Huurne
0 siblings, 0 replies; 3+ messages in thread
From: Maarten ter Huurne @ 2016-02-28 15:20 UTC (permalink / raw)
To: Dan Williams, Jiri Kosina; +Cc: linux-kernel, Maarten ter Huurne
check_sync() calls bucket_find_contain(), which in turn calls
dma_get_max_seg_size(), which dereferences the device pointer.
Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
---
lib/dma-debug.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index 4a1515f..4960402 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -1194,6 +1194,13 @@ static void check_sync(struct device *dev,
struct hash_bucket *bucket;
unsigned long flags;
+ if (!ref->dev) {
+ err_printk(dev, NULL, "DMA-API: device driver passes NULL "
+ "for device to DMA sync function; "
+ "cannot check usage\n");
+ return;
+ }
+
bucket = get_hash_bucket(ref, &flags);
entry = bucket_find_contain(&bucket, ref, &flags);
--
2.6.2
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2016-11-08 0:39 UTC | newest]
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2016-11-08 0:38 ` Andrew Morton
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