The patch titled
Subject: mm: vmalloc must set pte via arch code
has been added to the -mm mm-unstable branch. Its filename is
mm-vmalloc-must-set-pte-via-arch-code.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmalloc-must-set-pte-via-arch-code.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Ryan Roberts <ryan.roberts@xxxxxxx>
Subject: mm: vmalloc must set pte via arch code
Date: Fri, 2 Jun 2023 10:29:46 +0100
Patch series "Fixes for pte encapsulation bypasses", v3.
A series to improve the encapsulation of pte entries by disallowing
non-arch code from directly dereferencing pte_t pointers.
This patch (of 4):
It is bad practice to directly set pte entries within a pte table.
Instead all modifications must go through arch-provided helpers such as
set_pte_at() to give the arch code visibility and allow it to check (and
potentially modify) the operation.
Link: https://lkml.kernel.org/r/20230602092949.545577-1-ryan.roberts@xxxxxxx
Link: https://lkml.kernel.org/r/20230602092949.545577-2-ryan.roberts@xxxxxxx
Fixes: 3e9a9e256b1e ("mm: add a vmap_pfn function")
Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx>
Reviewed-by: Zi Yan <ziy@xxxxxxxxxx>
Acked-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Reviewed-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: SeongJae Park <sj@xxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmalloc.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/mm/vmalloc.c~mm-vmalloc-must-set-pte-via-arch-code
+++ a/mm/vmalloc.c
@@ -2944,10 +2944,16 @@ struct vmap_pfn_data {
static int vmap_pfn_apply(pte_t *pte, unsigned long addr, void *private)
{
struct vmap_pfn_data *data = private;
+ unsigned long pfn = data->pfns[data->idx];
+ pte_t ptent;
- if (WARN_ON_ONCE(pfn_valid(data->pfns[data->idx])))
+ if (WARN_ON_ONCE(pfn_valid(pfn)))
return -EINVAL;
- *pte = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot));
+
+ ptent = pte_mkspecial(pfn_pte(pfn, data->prot));
+ set_pte_at(&init_mm, addr, pte, ptent);
+
+ data->idx++;
return 0;
}
_
Patches currently in -mm which might be from ryan.roberts@xxxxxxx are
mm-vmalloc-must-set-pte-via-arch-code.patch
mm-damon-ops-common-atomically-test-and-clear-young-on-ptes-and-pmds.patch
mm-damon-ops-common-refactor-to-use-ptepmdp_clear_young_notify.patch
mm-fix-failure-to-unmap-pte-on-highmem-systems.patch
