The patch titled
Subject: mm/debug_vm_pgtable: fix corrupted page flag
has been added to the -mm tree. Its filename is
mm-debug_vm_pgtable-fix-corrupted-page-flag.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-debug_vm_pgtable-fix-corrupted-page-flag.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-debug_vm_pgtable-fix-corrupted-page-flag.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Gavin Shan <gshan@xxxxxxxxxx>
Subject: mm/debug_vm_pgtable: fix corrupted page flag
In page table entry modifying tests, set_xxx_at() are used to populate the
page table entries. On ARM64, PG_arch_1 is set to the target page flag if
execution permission is given. The page flag is kept when the page is
free'd to buddy's free area list. However, it will trigger page checking
failure when it's pulled from the buddy's free area list, as the following
warning messages indicate.
BUG: Bad page state in process memhog pfn:08000
page:0000000015c0a628 refcount:0 mapcount:0 \
mapping:0000000000000000 index:0x1 pfn:0x8000
flags: 0x7ffff8000000800(arch_1|node=0|zone=0|lastcpupid=0xfffff)
raw: 07ffff8000000800 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag(s) set
This fixes the issue by clearing PG_arch_1 through flush_dcache_page()
after set_xxx_at() is called.
Link: https://lkml.kernel.org/r/20210719130613.334901-13-gshan@xxxxxxxxxx
Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/debug_vm_pgtable.c | 32 ++++++++++++++++++++++++++++----
1 file changed, 28 insertions(+), 4 deletions(-)
--- a/mm/debug_vm_pgtable.c~mm-debug_vm_pgtable-fix-corrupted-page-flag
+++ a/mm/debug_vm_pgtable.c
@@ -29,6 +29,8 @@
#include <linux/start_kernel.h>
#include <linux/sched/mm.h>
#include <linux/io.h>
+
+#include <asm/cacheflush.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
@@ -118,6 +120,7 @@ static void __init pte_basic_tests(struc
static void __init pte_advanced_tests(struct pgtable_debug_args *args)
{
+ struct page *page;
pte_t pte;
/*
@@ -127,13 +130,16 @@ static void __init pte_advanced_tests(st
*/
pr_debug("Validating PTE advanced\n");
- if (args->pte_pfn == ULONG_MAX) {
+ page = (args->pte_pfn != ULONG_MAX) ?
+ pfn_to_page(args->pte_pfn) : NULL;
+ if (!page) {
pr_debug("%s: Skipped\n", __func__);
return;
}
pte = pfn_pte(args->pte_pfn, args->page_prot);
set_pte_at(args->mm, args->vaddr, args->ptep, pte);
+ flush_dcache_page(page);
ptep_set_wrprotect(args->mm, args->vaddr, args->ptep);
pte = ptep_get(args->ptep);
WARN_ON(pte_write(pte));
@@ -145,6 +151,7 @@ static void __init pte_advanced_tests(st
pte = pte_wrprotect(pte);
pte = pte_mkclean(pte);
set_pte_at(args->mm, args->vaddr, args->ptep, pte);
+ flush_dcache_page(page);
pte = pte_mkwrite(pte);
pte = pte_mkdirty(pte);
ptep_set_access_flags(args->vma, args->vaddr, args->ptep, pte, 1);
@@ -157,6 +164,7 @@ static void __init pte_advanced_tests(st
pte = pfn_pte(args->pte_pfn, args->page_prot);
pte = pte_mkyoung(pte);
set_pte_at(args->mm, args->vaddr, args->ptep, pte);
+ flush_dcache_page(page);
ptep_test_and_clear_young(args->vma, args->vaddr, args->ptep);
pte = ptep_get(args->ptep);
WARN_ON(pte_young(pte));
@@ -215,6 +223,7 @@ static void __init pmd_basic_tests(struc
static void __init pmd_advanced_tests(struct pgtable_debug_args *args)
{
+ struct page *page;
pmd_t pmd;
unsigned long vaddr = (args->vaddr & HPAGE_PMD_MASK);
@@ -222,7 +231,9 @@ static void __init pmd_advanced_tests(st
return;
pr_debug("Validating PMD advanced\n");
- if (args->pmd_pfn == ULONG_MAX) {
+ page = (args->pmd_pfn != ULONG_MAX) ?
+ pfn_to_page(args->pmd_pfn) : NULL;
+ if (!page) {
pr_debug("%s: Skipped\n", __func__);
return;
}
@@ -231,6 +242,7 @@ static void __init pmd_advanced_tests(st
pmd = pfn_pmd(args->pmd_pfn, args->page_prot);
set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
+ flush_dcache_page(page);
pmdp_set_wrprotect(args->mm, vaddr, args->pmdp);
pmd = READ_ONCE(*(args->pmdp));
WARN_ON(pmd_write(pmd));
@@ -242,6 +254,7 @@ static void __init pmd_advanced_tests(st
pmd = pmd_wrprotect(pmd);
pmd = pmd_mkclean(pmd);
set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
+ flush_dcache_page(page);
pmd = pmd_mkwrite(pmd);
pmd = pmd_mkdirty(pmd);
pmdp_set_access_flags(args->vma, vaddr, args->pmdp, pmd, 1);
@@ -254,6 +267,7 @@ static void __init pmd_advanced_tests(st
pmd = pmd_mkhuge(pfn_pmd(args->pmd_pfn, args->page_prot));
pmd = pmd_mkyoung(pmd);
set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
+ flush_dcache_page(page);
pmdp_test_and_clear_young(args->vma, vaddr, args->pmdp);
pmd = READ_ONCE(*(args->pmdp));
WARN_ON(pmd_young(pmd));
@@ -340,6 +354,7 @@ static void __init pud_basic_tests(struc
static void __init pud_advanced_tests(struct pgtable_debug_args *args)
{
+ struct page *page;
unsigned long vaddr = (args->vaddr & HPAGE_PUD_MASK);
pud_t pud;
@@ -347,13 +362,16 @@ static void __init pud_advanced_tests(st
return;
pr_debug("Validating PUD advanced\n");
- if (args->pud_pfn == ULONG_MAX) {
+ page = (args->pud_pfn != ULONG_MAX) ?
+ pfn_to_page(args->pud_pfn) : NULL;
+ if (!page) {
pr_debug("%s: Skipped\n", __func__);
return;
}
pud = pfn_pud(args->pud_pfn, args->page_prot);
set_pud_at(args->mm, vaddr, args->pudp, pud);
+ flush_dcache_page(page);
pudp_set_wrprotect(args->mm, vaddr, args->pudp);
pud = READ_ONCE(*(args->pudp));
WARN_ON(pud_write(pud));
@@ -367,6 +385,7 @@ static void __init pud_advanced_tests(st
pud = pud_wrprotect(pud);
pud = pud_mkclean(pud);
set_pud_at(args->mm, vaddr, args->pudp, pud);
+ flush_dcache_page(page);
pud = pud_mkwrite(pud);
pud = pud_mkdirty(pud);
pudp_set_access_flags(args->vma, vaddr, args->pudp, pud, 1);
@@ -382,6 +401,7 @@ static void __init pud_advanced_tests(st
pud = pfn_pud(args->pud_pfn, args->page_prot);
pud = pud_mkyoung(pud);
set_pud_at(args->mm, vaddr, args->pudp, pud);
+ flush_dcache_page(page);
pudp_test_and_clear_young(args->vma, vaddr, args->pudp);
pud = READ_ONCE(*(args->pudp));
WARN_ON(pud_young(pud));
@@ -596,10 +616,13 @@ static void __init pgd_populate_tests(st
static void __init pte_clear_tests(struct pgtable_debug_args *args)
{
+ struct page *page;
pte_t pte;
pr_debug("Validating PTE clear\n");
- if (args->pte_pfn == ULONG_MAX) {
+ page = (args->pte_pfn != ULONG_MAX) ?
+ pfn_to_page(args->pte_pfn) : NULL;
+ if (!page) {
pr_debug("%s: Skipped\n", __func__);
return;
}
@@ -609,6 +632,7 @@ static void __init pte_clear_tests(struc
pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
#endif
set_pte_at(args->mm, args->vaddr, args->ptep, pte);
+ flush_dcache_page(page);
barrier();
pte_clear(args->mm, args->vaddr, args->ptep);
pte = ptep_get(args->ptep);
_
Patches currently in -mm which might be from gshan@xxxxxxxxxx are
mm-debug_vm_pgtable-introduce-struct-pgtable_debug_args.patch
mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-basic-tests.patch
mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-leaf-and-savewrite-tests.patch
mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-protnone-and-devmap-tests.patch
mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-soft_dirty-and-swap-tests.patch
mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-migration-and-thp-tests.patch
mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-pte-modifying-tests.patch
mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-pmd-modifying-tests.patch
mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-pud-modifying-tests.patch
mm-debug_vm_pgtable-use-struct-pgtable_debug_args-in-pgd-and-p4d-modifying-tests.patch
mm-debug_vm_pgtable-remove-unused-code.patch
mm-debug_vm_pgtable-fix-corrupted-page-flag.patch
