iommufd/driver: Fix counter initialization for counted_by annotation

[PATCH] iommufd/driver: Fix counter initialization for counted_by annotation

Posted by Gustavo A. R. Silva 3 months ago

One of the requirements for counted_by annotations is that the counter
member must be initialized before the first reference to the
flexible-array member.

Move the vevent->data_len = data_len; initialization to before the
first access to flexible array vevent->event_data.

Cc: stable@vger.kernel.org
Fixes: e8e1ef9b77a7 ("iommufd/viommu: Add iommufd_viommu_report_event helper")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/iommu/iommufd/driver.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c
index 6f1010da221c..21d4a35538f6 100644
--- a/drivers/iommu/iommufd/driver.c
+++ b/drivers/iommu/iommufd/driver.c
@@ -161,8 +161,8 @@ int iommufd_viommu_report_event(struct iommufd_viommu *viommu,
 		vevent = &veventq->lost_events_header;
 		goto out_set_header;
 	}
-	memcpy(vevent->event_data, event_data, data_len);
 	vevent->data_len = data_len;
+	memcpy(vevent->event_data, event_data, data_len);
 	veventq->num_events++;
 
 out_set_header:
-- 
2.43.0

Re: [PATCH] iommufd/driver: Fix counter initialization for counted_by annotation

Posted by Jason Gunthorpe 2 months, 3 weeks ago

On Tue, Nov 11, 2025 at 06:01:24PM +0900, Gustavo A. R. Silva wrote:
> One of the requirements for counted_by annotations is that the counter
> member must be initialized before the first reference to the
> flexible-array member.
> 
> Move the vevent->data_len = data_len; initialization to before the
> first access to flexible array vevent->event_data.
> 
> Cc: stable@vger.kernel.org
> Fixes: e8e1ef9b77a7 ("iommufd/viommu: Add iommufd_viommu_report_event helper")
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>  drivers/iommu/iommufd/driver.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied, thanks

Jason

RE: [PATCH] iommufd/driver: Fix counter initialization for counted_by annotation

Posted by Tian, Kevin 2 months, 3 weeks ago

> From: Gustavo A. R. Silva <gustavoars@kernel.org>
> Sent: Tuesday, November 11, 2025 5:01 PM
> 
> One of the requirements for counted_by annotations is that the counter
> member must be initialized before the first reference to the
> flexible-array member.
> 
> Move the vevent->data_len = data_len; initialization to before the
> first access to flexible array vevent->event_data.
> 
> Cc: stable@vger.kernel.org
> Fixes: e8e1ef9b77a7 ("iommufd/viommu: Add
> iommufd_viommu_report_event helper")
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

Re: [PATCH] iommufd/driver: Fix counter initialization for counted_by annotation

Posted by Nicolin Chen 3 months ago

On Tue, Nov 11, 2025 at 06:01:24PM +0900, Gustavo A. R. Silva wrote:
> One of the requirements for counted_by annotations is that the counter
> member must be initialized before the first reference to the
> flexible-array member.
> 
> Move the vevent->data_len = data_len; initialization to before the
> first access to flexible array vevent->event_data.
> 
> Cc: stable@vger.kernel.org
> Fixes: e8e1ef9b77a7 ("iommufd/viommu: Add iommufd_viommu_report_event helper")
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
 
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>