On 20.03.21 10:36, Miaohe Lin wrote:
If the zone device page does not belong to un-addressable device memory,
the variable entry will be uninitialized and lead to indeterminate pte
entry ultimately. Fix this unexpectant case and warn about it.
s/unexpectant/unexpected/
Fixes: df6ad69838fc ("mm/device-public-memory: device memory cache coherent with CPU")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
mm/migrate.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/mm/migrate.c b/mm/migrate.c
index 20a3bf75270a..271081b014cb 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2972,6 +2972,13 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
swp_entry = make_device_private_entry(page, vma->vm_flags & VM_WRITE);
entry = swp_entry_to_pte(swp_entry);
+ } else {
+ /*
+ * For now we only support migrating to un-addressable
+ * device memory.
+ */
+ WARN_ON(1);
+ goto abort;
Fix it by crashing the kernel with panic_on_warn? :)
If this case can actual happen, than no WARN_ON() - rather a
pr_warn_once(). If this case cannot happen, why do we even care (it's
not a fix then)?
--
Thanks,
David / dhildenb
