+ mm-debug_vm_pgtable-more-pte_swp_exclusive-sanity-checks-fix.patch added to mm-unstable branch

+ mm-debug_vm_pgtable-more-pte_swp_exclusive-sanity-checks-fix.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: fixup: mm/debug_vm_pgtable: more pte_swp_exclusive() sanity checks
has been added to the -mm mm-unstable branch.  Its filename is
     mm-debug_vm_pgtable-more-pte_swp_exclusive-sanity-checks-fix.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-debug_vm_pgtable-more-pte_swp_exclusive-sanity-checks-fix.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: David Hildenbrand <david@redhat.com>
Subject: fixup: mm/debug_vm_pgtable: more pte_swp_exclusive() sanity checks
Date: Sat, 14 Jan 2023 16:47:12 +0100

generic_max_swapfile_size() is only available with CONFIG_SWAP -- which
makes sense, because without SWAP there are no swap files. Let's
simply probe manually which bits we can obtain after storing them in a
PTE, and properly call it "max swap offset", which is more generic for
a swap entry.

Link: https://lkml.kernel.org/r/6aaad548-cf48-77fa-9d6c-db83d724b2eb@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---


--- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-more-pte_swp_exclusive-sanity-checks-fix
+++ a/mm/debug_vm_pgtable.c
@@ -811,15 +811,17 @@ static void __init pmd_swap_soft_dirty_t
 static void __init pte_swap_exclusive_tests(struct pgtable_debug_args *args)
 {
 #ifdef __HAVE_ARCH_PTE_SWP_EXCLUSIVE
-	unsigned long max_swapfile_size = generic_max_swapfile_size();
+	unsigned long max_swap_offset;
 	swp_entry_t entry, entry2;
 	pte_t pte;
 
 	pr_debug("Validating PTE swap exclusive\n");
 
+	/* See generic_max_swapfile_size(): probe the maximum offset */
+	max_swap_offset = swp_offset(pte_to_swp_entry(swp_entry_to_pte(swp_entry(0, ~0UL))));
+
 	/* Create a swp entry with all possible bits set */
-	entry = swp_entry((1 << MAX_SWAPFILES_SHIFT) - 1,
-			  max_swapfile_size - 1);
+	entry = swp_entry((1 << MAX_SWAPFILES_SHIFT) - 1, max_swap_offset);
 
 	pte = swp_entry_to_pte(entry);
 	WARN_ON(pte_swp_exclusive(pte));
_

Patches currently in -mm which might be from david@redhat.com are

mm-userfaultfd-rely-on-vma-vm_page_prot-in-uffd_wp_range.patch
mm-userfaultfd-rely-on-vma-vm_page_prot-in-uffd_wp_range-fix.patch
mm-mprotect-drop-pgprot_t-parameter-from-change_protection.patch
mm-mprotect-drop-pgprot_t-parameter-from-change_protection-fix.patch
selftests-vm-cow-add-cow-tests-for-collapsing-of-pte-mapped-anon-thp.patch
mm-nommu-factor-out-check-for-nommu-shared-mappings-into-is_nommu_shared_mapping.patch
mm-nommu-dont-use-vm_mayshare-for-map_private-mappings.patch
drivers-misc-open-dice-dont-touch-vm_mayshare.patch
selftests-mm-define-madv_pageout-to-fix-compilation-issues.patch
mm-debug_vm_pgtable-more-pte_swp_exclusive-sanity-checks.patch
mm-debug_vm_pgtable-more-pte_swp_exclusive-sanity-checks-fix.patch
alpha-mm-support-__have_arch_pte_swp_exclusive.patch
arc-mm-support-__have_arch_pte_swp_exclusive.patch
arm-mm-support-__have_arch_pte_swp_exclusive.patch
csky-mm-support-__have_arch_pte_swp_exclusive.patch
hexagon-mm-support-__have_arch_pte_swp_exclusive.patch
ia64-mm-support-__have_arch_pte_swp_exclusive.patch
loongarch-mm-support-__have_arch_pte_swp_exclusive.patch
m68k-mm-remove-dummy-__swp-definitions-for-nommu.patch
m68k-mm-support-__have_arch_pte_swp_exclusive.patch
microblaze-mm-support-__have_arch_pte_swp_exclusive.patch
mips-mm-support-__have_arch_pte_swp_exclusive.patch
nios2-mm-refactor-swap-pte-layout.patch
nios2-mm-support-__have_arch_pte_swp_exclusive.patch
openrisc-mm-support-__have_arch_pte_swp_exclusive.patch
parisc-mm-support-__have_arch_pte_swp_exclusive.patch
powerpc-mm-support-__have_arch_pte_swp_exclusive-on-32bit-book3s.patch
powerpc-nohash-mm-support-__have_arch_pte_swp_exclusive.patch
riscv-mm-support-__have_arch_pte_swp_exclusive.patch
sh-mm-support-__have_arch_pte_swp_exclusive.patch
sparc-mm-support-__have_arch_pte_swp_exclusive-on-32bit.patch
sparc-mm-support-__have_arch_pte_swp_exclusive-on-64bit.patch
um-mm-support-__have_arch_pte_swp_exclusive.patch
x86-mm-support-__have_arch_pte_swp_exclusive-also-on-32bit.patch
xtensa-mm-support-__have_arch_pte_swp_exclusive.patch
mm-remove-__have_arch_pte_swp_exclusive.patch