| Message ID | 20220120042513.1648831-2-pasha.tatashin@soleen.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | page table check fixes and cleanups | expand |
On 19 Jan 2022, at 23:25, Pasha Tatashin wrote: > The pte entry that is used in pte_advanced_tests() is never removed from > the page table at the end of the test. > > The issue is detected by page_table_check, to repro compile kernel with > the following configs: > > CONFIG_DEBUG_VM_PGTABLE=y > CONFIG_PAGE_TABLE_CHECK=y > CONFIG_PAGE_TABLE_CHECK_ENFORCED=y > > During the boot the following BUG is printed: > > [ 7.483050][ T1] debug_vm_pgtable: [debug_vm_pgtable ]: > Validating architecture page tabs > [ 7.490930][ T1] ------------[ cut here ]------------ > [ 7.494926][ T1] kernel BUG at mm/page_table_check.c:194! > [ 7.499172][ T1] invalid opcode: 0000 [#1] PREEMPT SMP KASAN > [ 7.503610][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.16.0+ > [ 7.508600][ T1] Hardware name: QEMU Standard PC (i440FX + PIIX, > ... > > The entry should be properly removed from the page table before the page > is released to the free list. > > Fixes: a5c3b9ffb0f4 ("mm/debug_vm_pgtable: add tests validating advanced arch page table helpers") > > Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> > --- > mm/debug_vm_pgtable.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c > index a7ac97c76762..f7c5970f1719 100644 > --- a/mm/debug_vm_pgtable.c > +++ b/mm/debug_vm_pgtable.c > @@ -171,6 +171,7 @@ static void __init pte_advanced_tests(struct pgtable_debug_args *args) > ptep_test_and_clear_young(args->vma, args->vaddr, args->ptep); > pte = ptep_get(args->ptep); > WARN_ON(pte_young(pte)); > + ptep_get_and_clear_full(args->mm, args->vaddr, args->ptep, 1); > } > > static void __init pte_savedwrite_tests(struct pgtable_debug_args *args) > -- > 2.34.1.703.g22d0c6ccf7-goog LGTM. Thanks. Reviewed-by: Zi Yan <ziy@nvidia.com> and Tested-by: Zi Yan <ziy@nvidia.com> -- Best Regards, Yan, Zi
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index a7ac97c76762..f7c5970f1719 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -171,6 +171,7 @@ static void __init pte_advanced_tests(struct pgtable_debug_args *args) ptep_test_and_clear_young(args->vma, args->vaddr, args->ptep); pte = ptep_get(args->ptep); WARN_ON(pte_young(pte)); + ptep_get_and_clear_full(args->mm, args->vaddr, args->ptep, 1); } static void __init pte_savedwrite_tests(struct pgtable_debug_args *args)
The pte entry that is used in pte_advanced_tests() is never removed from the page table at the end of the test. The issue is detected by page_table_check, to repro compile kernel with the following configs: CONFIG_DEBUG_VM_PGTABLE=y CONFIG_PAGE_TABLE_CHECK=y CONFIG_PAGE_TABLE_CHECK_ENFORCED=y During the boot the following BUG is printed: [ 7.483050][ T1] debug_vm_pgtable: [debug_vm_pgtable ]: Validating architecture page tabs [ 7.490930][ T1] ------------[ cut here ]------------ [ 7.494926][ T1] kernel BUG at mm/page_table_check.c:194! [ 7.499172][ T1] invalid opcode: 0000 [#1] PREEMPT SMP KASAN [ 7.503610][ T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.16.0+ [ 7.508600][ T1] Hardware name: QEMU Standard PC (i440FX + PIIX, ... The entry should be properly removed from the page table before the page is released to the free list. Fixes: a5c3b9ffb0f4 ("mm/debug_vm_pgtable: add tests validating advanced arch page table helpers") Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> --- mm/debug_vm_pgtable.c | 1 + 1 file changed, 1 insertion(+)