On 7/25/22 11:49, Andrew Morton wrote:
On Fri, 22 Jul 2022 15:56:32 -0700 Ralph Campbell <rcampbell@xxxxxxxxxx> wrote:
If hmm_range_fault() is called with the HMM_PFN_REQ_FAULT flag and a
device private PTE is found, the hmm_range::dev_private_owner page is
used to determine if the device private page should not be faulted in.
However, if the device private page is not owned by the caller,
hmm_range_fault() returns an error instead of calling migrate_to_ram()
to fault in the page.
Could we please include here a description of the end-user visible
effects of the bug?
Cc: stable@xxxxxxxxxxxxxxx
Especially when proposing a -stable backport.
If I add the following, would that be sufficient?
Should I post a v3?
For example, if a page is migrated to GPU private
memory and a RDMA fault capable NIC tries to read the migrated page,
without this patch it will get an error. With this patch, the page will
be migrated back to system memory and the NIC will be able to read the
data.
