* [PATCH] misc/genwqe: ensure zero initialization
@ 2016-09-12 18:09 Sebastian Ott
2016-09-22 13:19 ` Frank Haverkamp
0 siblings, 1 reply; 3+ messages in thread
From: Sebastian Ott @ 2016-09-12 18:09 UTC (permalink / raw)
To: Frank Haverkamp, Greg Kroah-Hartman; +Cc: linux-kernel
Genwqe uses dma_alloc_coherent and depends on zero initialized memory. On
one occasion it ueses an explicit memset on others it uses un-initialized
memory.
This bug was covered because some archs actually return zero initialized
memory when using dma_alloc_coherent but this is by no means guaranteed.
Simply switch to dma_zalloc_coherent.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
---
drivers/misc/genwqe/card_ddcb.c | 2 --
drivers/misc/genwqe/card_utils.c | 4 ++--
2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/misc/genwqe/card_ddcb.c b/drivers/misc/genwqe/card_ddcb.c
index 353ee0c..ddfeefe 100644
--- a/drivers/misc/genwqe/card_ddcb.c
+++ b/drivers/misc/genwqe/card_ddcb.c
@@ -1048,8 +1048,6 @@ static int setup_ddcb_queue(struct genwqe_dev *cd, struct ddcb_queue *queue)
"[%s] **err: could not allocate DDCB **\n", __func__);
return -ENOMEM;
}
- memset(queue->ddcb_vaddr, 0, queue_size);
-
queue->ddcb_req = kzalloc(sizeof(struct ddcb_requ *) *
queue->ddcb_max, GFP_KERNEL);
if (!queue->ddcb_req) {
diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c
index 222367c..8a679ec 100644
--- a/drivers/misc/genwqe/card_utils.c
+++ b/drivers/misc/genwqe/card_utils.c
@@ -220,8 +220,8 @@ void *__genwqe_alloc_consistent(struct genwqe_dev *cd, size_t size,
if (get_order(size) > MAX_ORDER)
return NULL;
- return dma_alloc_coherent(&cd->pci_dev->dev, size, dma_handle,
- GFP_KERNEL);
+ return dma_zalloc_coherent(&cd->pci_dev->dev, size, dma_handle,
+ GFP_KERNEL);
}
void __genwqe_free_consistent(struct genwqe_dev *cd, size_t size,
--
2.5.5
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] misc/genwqe: ensure zero initialization
2016-09-12 18:09 [PATCH] misc/genwqe: ensure zero initialization Sebastian Ott
@ 2016-09-22 13:19 ` Frank Haverkamp
2016-09-23 10:06 ` Sebastian Ott
0 siblings, 1 reply; 3+ messages in thread
From: Frank Haverkamp @ 2016-09-22 13:19 UTC (permalink / raw)
To: Sebastian Ott; +Cc: Greg Kroah-Hartman, linux-kernel
Hi Sebastian,
> On 12.09.2016, at 20:09, Sebastian Ott <sebott@linux.vnet.ibm.com> wrote:
>
>
> Genwqe uses dma_alloc_coherent and depends on zero initialized memory. On
> one occasion it ueses an explicit memset on others it uses un-initialized
> memory.
>
> This bug was covered because some archs actually return zero initialized
> memory when using dma_alloc_coherent but this is by no means guaranteed.
> Simply switch to dma_zalloc_coherent.
Thanks for figuring this out. I hope you found all spots where this misassumption is done.
>
> Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
> ---
> drivers/misc/genwqe/card_ddcb.c | 2 --
> drivers/misc/genwqe/card_utils.c | 4 ++--
> 2 files changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/misc/genwqe/card_ddcb.c b/drivers/misc/genwqe/card_ddcb.c
> index 353ee0c..ddfeefe 100644
> --- a/drivers/misc/genwqe/card_ddcb.c
> +++ b/drivers/misc/genwqe/card_ddcb.c
> @@ -1048,8 +1048,6 @@ static int setup_ddcb_queue(struct genwqe_dev *cd, struct ddcb_queue *queue)
> "[%s] **err: could not allocate DDCB **\n", __func__);
> return -ENOMEM;
> }
> - memset(queue->ddcb_vaddr, 0, queue_size);
> -
> queue->ddcb_req = kzalloc(sizeof(struct ddcb_requ *) *
> queue->ddcb_max, GFP_KERNEL);
> if (!queue->ddcb_req) {
> diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c
> index 222367c..8a679ec 100644
> --- a/drivers/misc/genwqe/card_utils.c
> +++ b/drivers/misc/genwqe/card_utils.c
> @@ -220,8 +220,8 @@ void *__genwqe_alloc_consistent(struct genwqe_dev *cd, size_t size,
> if (get_order(size) > MAX_ORDER)
> return NULL;
>
> - return dma_alloc_coherent(&cd->pci_dev->dev, size, dma_handle,
> - GFP_KERNEL);
> + return dma_zalloc_coherent(&cd->pci_dev->dev, size, dma_handle,
> + GFP_KERNEL);
> }
>
> void __genwqe_free_consistent(struct genwqe_dev *cd, size_t size,
> --
> 2.5.5
>
I think this should be fine.
Signed-off-by: Frank Haverkamp <haver@linux.vnet.ibm.com>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] misc/genwqe: ensure zero initialization
2016-09-22 13:19 ` Frank Haverkamp
@ 2016-09-23 10:06 ` Sebastian Ott
0 siblings, 0 replies; 3+ messages in thread
From: Sebastian Ott @ 2016-09-23 10:06 UTC (permalink / raw)
To: Frank Haverkamp; +Cc: Greg Kroah-Hartman, linux-kernel
On Thu, 22 Sep 2016, Frank Haverkamp wrote:
> > On 12.09.2016, at 20:09, Sebastian Ott <sebott@linux.vnet.ibm.com> wrote:
> > Genwqe uses dma_alloc_coherent and depends on zero initialized memory. On
> > one occasion it ueses an explicit memset on others it uses un-initialized
> > memory.
> >
> > This bug was covered because some archs actually return zero initialized
> > memory when using dma_alloc_coherent but this is by no means guaranteed.
> > Simply switch to dma_zalloc_coherent.
>
> Thanks for figuring this out. I hope you found all spots where this misassumption is done.
Genwqe only uses the dma alloc API via a wrapper
(__genwqe_alloc_consistent) and I changed it there.
> I think this should be fine.
>
> Signed-off-by: Frank Haverkamp <haver@linux.vnet.ibm.com>
I changed that into an Ack. Seems more fitting here. Also I fixed a typo
in the patch description.
Greg, would you please take this one via your drivers/misc tree.
Thanks,
Sebastian
-------->8
misc/genwqe: ensure zero initialization
Genwqe uses dma_alloc_coherent and depends on zero initialized memory. On
one occasion it uses an explicit memset on others it uses un-initialized
memory.
This bug was covered because some archs actually return zero initialized
memory when using dma_alloc_coherent but this is by no means guaranteed.
Simply switch to dma_zalloc_coherent.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Acked-by: Frank Haverkamp <haver@linux.vnet.ibm.com>
---
drivers/misc/genwqe/card_ddcb.c | 2 --
drivers/misc/genwqe/card_utils.c | 4 ++--
2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/misc/genwqe/card_ddcb.c b/drivers/misc/genwqe/card_ddcb.c
index 353ee0c..ddfeefe 100644
--- a/drivers/misc/genwqe/card_ddcb.c
+++ b/drivers/misc/genwqe/card_ddcb.c
@@ -1048,8 +1048,6 @@ static int setup_ddcb_queue(struct genwqe_dev *cd, struct ddcb_queue *queue)
"[%s] **err: could not allocate DDCB **\n", __func__);
return -ENOMEM;
}
- memset(queue->ddcb_vaddr, 0, queue_size);
-
queue->ddcb_req = kzalloc(sizeof(struct ddcb_requ *) *
queue->ddcb_max, GFP_KERNEL);
if (!queue->ddcb_req) {
diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c
index 222367c..8a679ec 100644
--- a/drivers/misc/genwqe/card_utils.c
+++ b/drivers/misc/genwqe/card_utils.c
@@ -220,8 +220,8 @@ void *__genwqe_alloc_consistent(struct genwqe_dev *cd, size_t size,
if (get_order(size) > MAX_ORDER)
return NULL;
- return dma_alloc_coherent(&cd->pci_dev->dev, size, dma_handle,
- GFP_KERNEL);
+ return dma_zalloc_coherent(&cd->pci_dev->dev, size, dma_handle,
+ GFP_KERNEL);
}
void __genwqe_free_consistent(struct genwqe_dev *cd, size_t size,
--
2.5.5
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2016-09-23 10:06 UTC | newest]
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2016-09-12 18:09 [PATCH] misc/genwqe: ensure zero initialization Sebastian Ott
2016-09-22 13:19 ` Frank Haverkamp
2016-09-23 10:06 ` Sebastian Ott
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