From: Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>
Sent: Tuesday, September 5, 2023 1:24 PM
Hi Kevin,
I am trying to address this issue in below patch. Does it looks sane to
you?
iommu: Consolidate per-device fault data management
The per-device fault data is a data structure that is used to store
information about faults that occur on a device. This data is allocated
when IOPF is enabled on the device and freed when IOPF is disabled. The
data is used in the paths of iopf reporting, handling, responding, and
draining.
The fault data is protected by two locks:
- dev->iommu->lock: This lock is used to protect the allocation and
freeing of the fault data.
- dev->iommu->fault_parameter->lock: This lock is used to protect the
fault data itself.
Improve the iopf code to enforce this lock mechanism and add a reference
counter in the fault data to avoid use-after-free issue.
Can you elaborate the use-after-free issue and why a new user count
is required?
btw a Fix tag is required given this mislocking issue has been there for
quite some time...