| Message ID | 20220126060514.1574935-2-pasha.tatashin@soleen.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | page table check fixes and cleanups | expand |
On Wed, 26 Jan 2022, 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: > > [ 2.262821] debug_vm_pgtable: [debug_vm_pgtable ]: Validating > architecture page table helpers > [ 2.276826] ------------[ cut here ]------------ > [ 2.280426] kernel BUG at mm/page_table_check.c:162! > [ 2.284118] invalid opcode: 0000 [#1] PREEMPT SMP PTI > [ 2.287787] CPU: 0 PID: 1 Comm: swapper/0 Not tainted > 5.16.0-11413-g2c271fe77d52 #3 > [ 2.293226] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), > BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org > 04/01/2014 > ... > > 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> > Reviewed-by: Zi Yan <ziy@nvidia.com> > Tested-by: Zi Yan <ziy@nvidia.com> Acked-by: David Rientjes <rientjes@google.com> I think we also likely want: Cc: stable@vger.kernel.org # 5.9+
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index a7ac97c76762..db2abd9e415b 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -171,6 +171,8 @@ 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: [ 2.262821] debug_vm_pgtable: [debug_vm_pgtable ]: Validating architecture page table helpers [ 2.276826] ------------[ cut here ]------------ [ 2.280426] kernel BUG at mm/page_table_check.c:162! [ 2.284118] invalid opcode: 0000 [#1] PREEMPT SMP PTI [ 2.287787] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.16.0-11413-g2c271fe77d52 #3 [ 2.293226] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 ... 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> Reviewed-by: Zi Yan <ziy@nvidia.com> Tested-by: Zi Yan <ziy@nvidia.com> --- mm/debug_vm_pgtable.c | 2 ++ 1 file changed, 2 insertions(+)