On September 18, 2021 6:20:10 AM PDT, Len Baker len.baker@gmx.com wrote:
Hi,
On Sat, Sep 11, 2021 at 12:28:18PM +0200, Len Baker wrote:
As noted in the "Deprecated Interfaces, Language Features, Attributes, and Conventions" documentation [1], size calculations (especially multiplication) should not be performed in memory allocator (or similar) function arguments due to the risk of them overflowing. This could lead to values wrapping around and a smaller allocation being made than the caller was expecting. Using those allocations could lead to linear overflows of heap memory and other misbehaviors.
So, use the struct_size() helper to do the arithmetic instead of the argument "size + count * size" in the kzalloc() function.
[1] https://www.kernel.org/doc/html/v5.14/process/deprecated.html#open-coded-ari...
Signed-off-by: Len Baker len.baker@gmx.com
drivers/net/ethernet/microsoft/mana/hw_channel.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/microsoft/mana/hw_channel.c b/drivers/net/ethernet/microsoft/mana/hw_channel.c index 1a923fd99990..0efdc6c3c32a 100644 --- a/drivers/net/ethernet/microsoft/mana/hw_channel.c +++ b/drivers/net/ethernet/microsoft/mana/hw_channel.c @@ -398,9 +398,7 @@ static int mana_hwc_alloc_dma_buf(struct hw_channel_context *hwc, u16 q_depth, int err; u16 i;
- dma_buf = kzalloc(sizeof(*dma_buf) +
q_depth * sizeof(struct hwc_work_request),GFP_KERNEL);
- dma_buf = kzalloc(struct_size(dma_buf, reqs, q_depth), GFP_KERNEL); if (!dma_buf) return -ENOMEM;
-- 2.25.1
I have received a email from the linux-media subsystem telling that this patch is not applicable. The email is the following:
Hello,
The following patch (submitted by you) has been updated in Patchwork:
- linux-media: net: mana: Prefer struct_size over open coded arithmetic
was: New now: Not Applicable
- http://patchwork.linuxtv.org/project/linux-media/patch/20210911102818.3804-1...
- for: Linux Media kernel patches
This email is a notification only - you do not need to respond.
The question is: Why it is not applicable?. I have no received any bad comment and a "Reviewed-by:" tag from Haiyang Zhang. So, what is the reason for the "Not Applicable" state?.
That is the "Media" subsystem patch tracker. The patch appears to be for networking, so the Media tracker has marked it as "not applicable [to the media subsystem]".
The CC list for this patch seems rather wide (media, dri). I would have expected only netdev. Were you using scripts/get_maintainer.pl for getting addresses?
-Kees