The patch titled
Subject: mm: apply_to_pte_range warn and fail if a large pte is encountered
has been added to the -mm tree. Its filename is
mm-apply_to_pte_range-warn-and-fail-if-a-large-pte-is-encountered.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-apply_to_pte_range-warn-and-fail-if-a-large-pte-is-encountered.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-apply_to_pte_range-warn-and-fail-if-a-large-pte-is-encountered.patch
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The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Nicholas Piggin <npiggin@xxxxxxxxx>
Subject: mm: apply_to_pte_range warn and fail if a large pte is encountered
apply_to_pte_range might mistake a large pte for bad, or treat it as a
page table, resulting in a crash or corruption. Add a test to warn and
return error if large entries are found.
Link: https://lkml.kernel.org/r/20210317062402.533919-4-npiggin@xxxxxxxxx
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
Reviewed-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Ding Tianhong <dingtianhong@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 66 +++++++++++++++++++++++++++++++++++++-------------
1 file changed, 49 insertions(+), 17 deletions(-)
--- a/mm/memory.c~mm-apply_to_pte_range-warn-and-fail-if-a-large-pte-is-encountered
+++ a/mm/memory.c
@@ -2446,13 +2446,21 @@ static int apply_to_pmd_range(struct mm_
}
do {
next = pmd_addr_end(addr, end);
- if (create || !pmd_none_or_clear_bad(pmd)) {
- err = apply_to_pte_range(mm, pmd, addr, next, fn, data,
- create, mask);
- if (err)
- break;
+ if (pmd_none(*pmd) && !create)
+ continue;
+ if (WARN_ON_ONCE(pmd_leaf(*pmd)))
+ return -EINVAL;
+ if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) {
+ if (!create)
+ continue;
+ pmd_clear_bad(pmd);
}
+ err = apply_to_pte_range(mm, pmd, addr, next,
+ fn, data, create, mask);
+ if (err)
+ break;
} while (pmd++, addr = next, addr != end);
+
return err;
}
@@ -2474,13 +2482,21 @@ static int apply_to_pud_range(struct mm_
}
do {
next = pud_addr_end(addr, end);
- if (create || !pud_none_or_clear_bad(pud)) {
- err = apply_to_pmd_range(mm, pud, addr, next, fn, data,
- create, mask);
- if (err)
- break;
+ if (pud_none(*pud) && !create)
+ continue;
+ if (WARN_ON_ONCE(pud_leaf(*pud)))
+ return -EINVAL;
+ if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) {
+ if (!create)
+ continue;
+ pud_clear_bad(pud);
}
+ err = apply_to_pmd_range(mm, pud, addr, next,
+ fn, data, create, mask);
+ if (err)
+ break;
} while (pud++, addr = next, addr != end);
+
return err;
}
@@ -2502,13 +2518,21 @@ static int apply_to_p4d_range(struct mm_
}
do {
next = p4d_addr_end(addr, end);
- if (create || !p4d_none_or_clear_bad(p4d)) {
- err = apply_to_pud_range(mm, p4d, addr, next, fn, data,
- create, mask);
- if (err)
- break;
+ if (p4d_none(*p4d) && !create)
+ continue;
+ if (WARN_ON_ONCE(p4d_leaf(*p4d)))
+ return -EINVAL;
+ if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) {
+ if (!create)
+ continue;
+ p4d_clear_bad(p4d);
}
+ err = apply_to_pud_range(mm, p4d, addr, next,
+ fn, data, create, mask);
+ if (err)
+ break;
} while (p4d++, addr = next, addr != end);
+
return err;
}
@@ -2528,9 +2552,17 @@ static int __apply_to_page_range(struct
pgd = pgd_offset(mm, addr);
do {
next = pgd_addr_end(addr, end);
- if (!create && pgd_none_or_clear_bad(pgd))
+ if (pgd_none(*pgd) && !create)
continue;
- err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create, &mask);
+ if (WARN_ON_ONCE(pgd_leaf(*pgd)))
+ return -EINVAL;
+ if (!pgd_none(*pgd) && WARN_ON_ONCE(pgd_bad(*pgd))) {
+ if (!create)
+ continue;
+ pgd_clear_bad(pgd);
+ }
+ err = apply_to_p4d_range(mm, pgd, addr, next,
+ fn, data, create, &mask);
if (err)
break;
} while (pgd++, addr = next, addr != end);
_
Patches currently in -mm which might be from npiggin@xxxxxxxxx are
arm-mm-add-missing-pud_page-define-to-2-level-page-tables.patch
mm-vmalloc-fix-huge_vmap-regression-by-enabling-huge-pages-in-vmalloc_to_page.patch
mm-apply_to_pte_range-warn-and-fail-if-a-large-pte-is-encountered.patch
mm-vmalloc-rename-vmap__range-vmap_pages__range.patch
mm-ioremap-rename-ioremap__range-to-vmap__range.patch
mm-huge_vmap-arch-support-cleanup.patch
powerpc-inline-huge-vmap-supported-functions.patch
arm64-inline-huge-vmap-supported-functions.patch
x86-inline-huge-vmap-supported-functions.patch
mm-vmalloc-provide-fallback-arch-huge-vmap-support-functions.patch
mm-move-vmap_range-from-mm-ioremapc-to-mm-vmallocc.patch
mm-vmalloc-add-vmap_range_noflush-variant.patch
mm-vmalloc-hugepage-vmalloc-mappings.patch
powerpc-64s-radix-enable-huge-vmalloc-mappings.patch
