On 9/23/26 16:23, Kees Cook wrote:
On Wed, Sep 23, 2026 at 03:10:08PM +0900, Gustavo A. R. Silva wrote:
On 9/23/26 14:53, Bill Wendling wrote:
Add the "__counted_by_ptr" attribute to the buffer field of "struct
vmbus_gpadl". This allows compilers (GCC and Clang) to perform
compile-time and runtime bounds-checking when KASAN is enabled, preventing
potential out-of-bounds accesses to the GPADL buffer.
The fields "buffer" and "size" of "struct vmbus_gpadl" are assigned
exactly once, during GPADL establishment inside
"__vmbus_establish_gpadl()" in "drivers/hv/channel.c".
To ensure that the count field ("size") is initialized before the
pointer field ("buffer") is assigned, we reorder the assignments in
"__vmbus_establish_gpadl()" so that "gpadl->size" is written before
"gpadl->buffer".
Cc: [email protected]
Assisted-by: LLM
Signed-off-by: Bill Wendling <[email protected]>
---
drivers/hv/channel.c | 2 +-
include/linux/hyperv.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 7e4cc6f55237..7042de2dd481 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -548,8 +548,8 @@ static int __vmbus_establish_gpadl(struct vmbus_channel
*channel,
/* At this point, we received the gpadl created msg */
gpadl->gpadl_handle = gpadlmsg->gpadl;
- gpadl->buffer = kbuffer;
gpadl->size = size;
+ gpadl->buffer = kbuffer;
I think in some cases these subtle changes are worth a short but
informative comment saying that the _counter_ must be initialized
before the first reference to the pointer.
But that's only for dereferencing it... there's no ordering requirement
Ah yes, I got a bit carried away by the change itself.
here at all (and I think swapping order is needless churn). Neither
order is correct: only having them both set before dereferencing
"buffer" is required.
Yes; maybe this is something the LLM should learn.
Thanks
-Gustavo
