From: Peter Collingbourne <pcc@xxxxxxxxxx>
commit 6dca4ac6fc91fd41ea4d6c4511838d37f4e0eab2 upstream.
Commit c145e0b47c77 ("mm: streamline COW logic in do_swap_page()") moved
the call to swap_free() before the call to set_pte_at(), which meant that
the MTE tags could end up being freed before set_pte_at() had a chance to
restore them. Fix it by adding a call to the arch_swap_restore() hook
before the call to swap_free().
Link: https://lkml.kernel.org/r/20230523004312.1807357-2-pcc@xxxxxxxxxx
Link: https://linux-review.googlesource.com/id/I6470efa669e8bd2f841049b8c61020c510678965
Fixes: c145e0b47c77 ("mm: streamline COW logic in do_swap_page()")
Signed-off-by: Peter Collingbourne <pcc@xxxxxxxxxx>
Reported-by: Qun-wei Lin <Qun-wei.Lin@xxxxxxxxxxxx>
Closes: https://lore.kernel.org/all/5050805753ac469e8d727c797c2218a9d780d434.camel@xxxxxxxxxxxx/
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Acked-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Reviewed-by: Steven Price <steven.price@xxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [6.1+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3915,6 +3915,13 @@ vm_fault_t do_swap_page(struct vm_fault
}
/*
+ * Some architectures may have to restore extra metadata to the page
+ * when reading from swap. This metadata may be indexed by swap entry
+ * so this must be called before swap_free().
+ */
+ arch_swap_restore(entry, folio);
+
+ /*
* Remove the swap entry and conditionally try to free up the swapcache.
* We're already holding a reference on the page but haven't mapped it
* yet.
