Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.10 17/74] mm/debug_vm_pgtable: remove pte entry from the page table | Date | Mon, 7 Feb 2022 12:06:15 +0100 |
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From: Pasha Tatashin <pasha.tatashin@soleen.com>
commit fb5222aae64fe25e5f3ebefde8214dcf3ba33ca5 upstream.
Patch series "page table check fixes and cleanups", v5.
This patch (of 4):
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:
debug_vm_pgtable: [debug_vm_pgtable ]: Validating architecture page table helpers ------------[ cut here ]------------ kernel BUG at mm/page_table_check.c:162! invalid opcode: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.16.0-11413-g2c271fe77d52 #3 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.
Link: https://lkml.kernel.org/r/20220131203249.2832273-1-pasha.tatashin@soleen.com Link: https://lkml.kernel.org/r/20220131203249.2832273-2-pasha.tatashin@soleen.com 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> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Wei Xu <weixugc@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> [5.9+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- mm/debug_vm_pgtable.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -128,6 +128,8 @@ static void __init pte_advanced_tests(st ptep_test_and_clear_young(vma, vaddr, ptep); pte = ptep_get(ptep); WARN_ON(pte_young(pte)); + + ptep_get_and_clear_full(mm, vaddr, ptep, 1); } static void __init pte_savedwrite_tests(unsigned long pfn, pgprot_t prot)
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