The patch titled
Subject: mm: call arch_swap_restore() from do_swap_page()
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-call-arch_swap_restore-from-do_swap_page.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-call-arch_swap_restore-from-do_swap_page.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Peter Collingbourne <pcc@xxxxxxxxxx>
Subject: mm: call arch_swap_restore() from do_swap_page()
Date: Mon, 22 May 2023 17:43:08 -0700
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>
---
mm/memory.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/mm/memory.c~mm-call-arch_swap_restore-from-do_swap_page
+++ a/mm/memory.c
@@ -3954,6 +3954,13 @@ 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.
_
Patches currently in -mm which might be from pcc@xxxxxxxxxx are
mm-call-arch_swap_restore-from-do_swap_page.patch
