user/sven/linux.git/mm/debug_vm_pgtable.c, branch v5.15.76

mm/debug_vm_pgtable: remove pte entry from the page table

2022-02-08T17:34:05Z

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 Reviewed-by: Zi Yan Tested-by: Zi Yan Acked-by: David Rientjes Reviewed-by: Anshuman Khandual Cc: Paul Turner Cc: Wei Xu Cc: Greg Thelen Cc: Ingo Molnar Cc: Will Deacon Cc: Mike Rapoport Cc: Dave Hansen Cc: H. Peter Anvin Cc: Aneesh Kumar K.V Cc: Jiri Slaby Cc: Muchun Song Cc: Hugh Dickins Cc: [5.9+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/debug_vm_pgtable: fix corrupted page flag

2021-09-03T16:58:10Z

In page table entry modifying tests, set_xxx_at() are used to populate the page table entries. On ARM64, PG_arch_1 (PG_dcache_clean) flag is set to the target page flag if execution permission is given. The logic exits since commit 4f04d8f00545 ("arm64: MMU definitions"). 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. For architectures other than ARM64, the unexpected overhead of cache flushing is acceptable. Link: https://lkml.kernel.org/r/20210809092631.1888748-13-gshan@redhat.com Fixes: a5c3b9ffb0f4 ("mm/debug_vm_pgtable: add tests validating advanced arch page table helpers") Signed-off-by: Gavin Shan Reviewed-by: Anshuman Khandual Tested-by: Christophe Leroy [powerpc 8xx] Tested-by: Gerald Schaefer [s390] Cc: Aneesh Kumar K.V Cc: Catalin Marinas Cc: Chunyu Hu Cc: Qian Cai Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable: remove unused code

2021-09-03T16:58:10Z

The variables used by old implementation isn't needed as we switched to "struct pgtable_debug_args". Lets remove them and related code in debug_vm_pgtable(). Link: https://lkml.kernel.org/r/20210809092631.1888748-12-gshan@redhat.com Signed-off-by: Gavin Shan Reviewed-by: Anshuman Khandual Tested-by: Christophe Leroy [powerpc 8xx] Tested-by: Gerald Schaefer [s390] Cc: Aneesh Kumar K.V Cc: Catalin Marinas Cc: Chunyu Hu Cc: Qian Cai Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable: use struct pgtable_debug_args in PGD and P4D modifying tests

2021-09-03T16:58:10Z

This uses struct pgtable_debug_args in PGD/P4D modifying tests. No allocated huge page is used in these tests. Besides, the unused variable @saved_p4dp and @saved_pudp are dropped. Link: https://lkml.kernel.org/r/20210809092631.1888748-11-gshan@redhat.com Signed-off-by: Gavin Shan Reviewed-by: Anshuman Khandual Tested-by: Christophe Leroy [powerpc 8xx] Tested-by: Gerald Schaefer [s390] Cc: Aneesh Kumar K.V Cc: Catalin Marinas Cc: Chunyu Hu Cc: Qian Cai Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable: use struct pgtable_debug_args in PUD modifying tests

2021-09-03T16:58:09Z

This uses struct pgtable_debug_args in PUD modifying tests. The allocated huge page is used when set_pud_at() is used. The corresponding tests are skipped if the huge page doesn't exist. Besides, the following unused variables in debug_vm_pgtable() are dropped: @prot, @paddr, @pud_aligned. Link: https://lkml.kernel.org/r/20210809092631.1888748-10-gshan@redhat.com Signed-off-by: Gavin Shan Reviewed-by: Anshuman Khandual Tested-by: Christophe Leroy [powerpc 8xx] Tested-by: Gerald Schaefer [s390] Cc: Aneesh Kumar K.V Cc: Catalin Marinas Cc: Chunyu Hu Cc: Qian Cai Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable: use struct pgtable_debug_args in PMD modifying tests

2021-09-03T16:58:09Z

This uses struct pgtable_debug_args in PMD modifying tests. The allocated huge page is used when set_pmd_at() is used. The corresponding tests are skipped if the huge page doesn't exist. Besides, the unused variable @pmd_aligned in debug_vm_pgtable() is dropped. Link: https://lkml.kernel.org/r/20210809092631.1888748-9-gshan@redhat.com Signed-off-by: Gavin Shan Reviewed-by: Anshuman Khandual Tested-by: Christophe Leroy [powerpc 8xx] Tested-by: Gerald Schaefer [s390] Cc: Aneesh Kumar K.V Cc: Catalin Marinas Cc: Chunyu Hu Cc: Qian Cai Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable: use struct pgtable_debug_args in PTE modifying tests

2021-09-03T16:58:09Z

This uses struct pgtable_debug_args in PTE modifying tests. The allocated page is used as set_pte_at() is used there. The tests are skipped if the allocated page doesn't exist. It's notable that args->ptep need to be mapped before the tests. The reason why we don't map args->ptep at the beginning is PTE entry is only mapped and accessible in atomic context when CONFIG_HIGHPTE is enabled. So we avoid to do that so that atomic context is only enabled if needed. Besides, the unused variable @pte_aligned and @ptep in debug_vm_pgtable() are dropped. Link: https://lkml.kernel.org/r/20210809092631.1888748-8-gshan@redhat.com Signed-off-by: Gavin Shan Reviewed-by: Anshuman Khandual Tested-by: Christophe Leroy [powerpc 8xx] Tested-by: Gerald Schaefer [s390] Cc: Aneesh Kumar K.V Cc: Catalin Marinas Cc: Chunyu Hu Cc: Qian Cai Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable: use struct pgtable_debug_args in migration and thp tests

2021-09-03T16:58:09Z

This uses struct pgtable_debug_args in the migration and thp test functions. It's notable that the pre-allocated page is used in swap_migration_tests() as set_pte_at() is used there. Link: https://lkml.kernel.org/r/20210809092631.1888748-7-gshan@redhat.com Signed-off-by: Gavin Shan Reviewed-by: Anshuman Khandual Tested-by: Christophe Leroy [powerpc 8xx] Tested-by: Gerald Schaefer [s390] Cc: Aneesh Kumar K.V Cc: Catalin Marinas Cc: Chunyu Hu Cc: Qian Cai Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable: use struct pgtable_debug_args in soft_dirty and swap tests

2021-09-03T16:58:09Z

This uses struct pgtable_debug_args in the soft_dirty and swap test functions. Link: https://lkml.kernel.org/r/20210809092631.1888748-6-gshan@redhat.com Signed-off-by: Gavin Shan Reviewed-by: Anshuman Khandual Tested-by: Christophe Leroy [powerpc 8xx] Tested-by: Gerald Schaefer [s390] Cc: Aneesh Kumar K.V Cc: Catalin Marinas Cc: Chunyu Hu Cc: Qian Cai Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/debug_vm_pgtable: use struct pgtable_debug_args in protnone and devmap tests

2021-09-03T16:58:09Z

This uses struct pgtable_debug_args in protnone and devmap test functions. After that, the unused variable @protnone in debug_vm_pgtable() is dropped. Link: https://lkml.kernel.org/r/20210809092631.1888748-5-gshan@redhat.com Signed-off-by: Gavin Shan Reviewed-by: Anshuman Khandual Tested-by: Christophe Leroy [powerpc 8xx] Tested-by: Gerald Schaefer [s390] Cc: Aneesh Kumar K.V Cc: Catalin Marinas Cc: Chunyu Hu Cc: Qian Cai Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds