user/sven/linux.git/mm/debug_vm_pgtable.c, branch v6.3.12

mm: remove __HAVE_ARCH_PTE_SWP_EXCLUSIVE

2023-02-03T06:33:11Z

__HAVE_ARCH_PTE_SWP_EXCLUSIVE is now supported by all architectures that support swp PTEs, so let's drop it. Link: https://lkml.kernel.org/r/20230113171026.582290-27-david@redhat.com Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton

mm/debug_vm_pgtable: more pte_swp_exclusive() sanity checks

2023-02-03T06:33:05Z

Patch series "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap PTEs". This is the follow-up on [1]: [PATCH v2 0/8] mm: COW fixes part 3: reliable GUP R/W FOLL_GET of anonymous pages After we implemented __HAVE_ARCH_PTE_SWP_EXCLUSIVE on most prominent enterprise architectures, implement __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all remaining architectures that support swap PTEs. This makes sure that exclusive anonymous pages will stay exclusive, even after they were swapped out -- for example, making GUP R/W FOLL_GET of anonymous pages reliable. Details can be found in [1]. This primarily fixes remaining known O_DIRECT memory corruptions that can happen on concurrent swapout, whereby we can lose DMA reads to a page (modifying the user page by writing to it). To verify, there are two test cases (requiring swap space, obviously): (1) The O_DIRECT+swapout test case [2] from Andrea. This test case tries triggering a race condition. (2) My vmsplice() test case [3] that tries to detect if the exclusive marker was lost during swapout, not relying on a race condition. For example, on 32bit x86 (with and without PAE), my test case fails without these patches: $ ./test_swp_exclusive FAIL: page was replaced during COW But succeeds with these patches: $ ./test_swp_exclusive PASS: page was not replaced during COW Why implement __HAVE_ARCH_PTE_SWP_EXCLUSIVE for all architectures, even the ones where swap support might be in a questionable state? This is the first step towards removing "readable_exclusive" migration entries, and instead using pte_swp_exclusive() also with (readable) migration entries instead (as suggested by Peter). The only missing piece for that is supporting pmd_swp_exclusive() on relevant architectures with THP migration support. As all relevant architectures now implement __HAVE_ARCH_PTE_SWP_EXCLUSIVE,, we can drop __HAVE_ARCH_PTE_SWP_EXCLUSIVE in the last patch. I tried cross-compiling all relevant setups and tested on x86 and sparc64 so far. CCing arch maintainers only on this cover letter and on the respective patch(es). [1] https://lkml.kernel.org/r/20220329164329.208407-1-david@redhat.com [2] https://gitlab.com/aarcange/kernel-testcases-for-v5.11/-/blob/main/page_count_do_wp_page-swap.c [3] https://gitlab.com/davidhildenbrand/scratchspace/-/blob/main/test_swp_exclusive.c This patch (of 26): We want to implement __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures. Let's extend our sanity checks, especially testing that our PTE bit does not affect: * is_swap_pte() -> pte_present() and pte_none() * the swap entry + type * pte_swp_soft_dirty() Especially, the pfn_pte() is dodgy when the swap PTE layout differs heavily from ordinary PTEs. Let's properly construct a swap PTE from swap type+offset. [david@redhat.com: fix build] Link: https://lkml.kernel.org/r/6aaad548-cf48-77fa-9d6c-db83d724b2eb@redhat.com Link: https://lkml.kernel.org/r/20230113171026.582290-1-david@redhat.com Link: https://lkml.kernel.org/r/20230113171026.582290-2-david@redhat.com Signed-off-by: David Hildenbrand Cc: Andrea Arcangeli Cc: Anton Ivanov Cc: Cc: Borislav Petkov (AMD) Cc: Brian Cain Cc: Christophe Leroy Cc: Chris Zankel Cc: Dave Hansen Cc: David S. Miller Cc: Dinh Nguyen Cc: Geert Uytterhoeven Cc: Greg Ungerer Cc: Guo Ren Cc: Helge Deller Cc: H. Peter Anvin (Intel) Cc: Huacai Chen Cc: Hugh Dickins Cc: Ingo Molnar Cc: Ivan Kokshaysky Cc: James Bottomley Cc: Jason Gunthorpe Cc: Johannes Berg Cc: John Hubbard Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Mike Rapoport Cc: Nadav Amit Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Xu Cc: Richard Henderson Cc: Richard Weinberger Cc: Rich Felker Cc: Russell King Cc: Stafford Horne Cc: Stefan Kristiansson Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Vineet Gupta Cc: Vlastimil Babka Cc: Xuerui Wang Cc: Yang Shi Cc: Yoshinori Sato Signed-off-by: Andrew Morton

mm/debug: use valid physical memory for pmd/pud tests

2023-01-19T01:12:59Z

The page table debug tests need a physical address to validate low-level page table manipulation with. The memory at this address is not actually touched, it just encoded in the page table entries at various levels during the tests only. Since the memory is not used, the code just picks the physical address of the start_kernel symbol. This value is then truncated to get a properly aligned address that is to be used for various tests. Because of the truncation, the address might not actually exist, or might not describe a complete huge page. That's not a problem for most tests, but the arch-specific code may check for attribute validity and consistency. The x86 version of {pud,pmd}_set_huge actually validates the MTRRs for the PMD/PUD range. This may fail with an address derived from start_kernel, depending on where the kernel was loaded and what the physical memory layout of the system is. This then leads to false negatives for the {pud,pmd}_set_huge tests. Avoid this by finding a properly aligned memory range that exists and is usable. If such a range is not found, skip the tests that needed it. [fvdl@google.com: v3] Link: https://lkml.kernel.org/r/20230110181208.1633879-1-fvdl@google.com Link: https://lkml.kernel.org/r/20230109174332.329366-1-fvdl@google.com Fixes: 399145f9eb6c ("mm/debug: add tests validating architecture page table helpers") Signed-off-by: Frank van der Linden Reviewed-by: Anshuman Khandual Signed-off-by: Andrew Morton

mm: remove unused savedwrite infrastructure

2022-11-30T23:58:49Z

NUMA hinting no longer uses savedwrite, let's rip it out. ... and while at it, drop __pte_write() and __pmd_write() on ppc64. Link: https://lkml.kernel.org/r/20221108174652.198904-7-david@redhat.com Signed-off-by: David Hildenbrand Cc: Andrea Arcangeli Cc: Anshuman Khandual Cc: Dave Chinner Cc: Hugh Dickins Cc: Linus Torvalds Cc: Mel Gorman Cc: Michael Ellerman Cc: Mike Rapoport Cc: Nadav Amit Cc: Nicholas Piggin Cc: Peter Xu Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: debug_vm_pgtable: use VM_ACCESS_FLAGS

2022-11-09T01:37:19Z

Directly use VM_ACCESS_FLAGS instead VMFLAGS. Link: https://lkml.kernel.org/r/20221019034945.93081-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: Alex Deucher Cc: "Christian König" Cc: Daniel Vetter Cc: Dave Hansen Cc: David Airlie Cc: Dinh Nguyen Cc: Jarkko Sakkinen Cc: "Pan, Xinhui" Signed-off-by: Andrew Morton

docs: rename Documentation/vm to Documentation/mm

2022-06-27T19:52:53Z

so it will be consistent with code mm directory and with Documentation/admin-guide/mm and won't be confused with virtual machines. Signed-off-by: Mike Rapoport Suggested-by: Matthew Wilcox Tested-by: Ira Weiny Acked-by: Jonathan Corbet Acked-by: Wu XiangCheng

mm/debug_vm_pgtable: add tests for __HAVE_ARCH_PTE_SWP_EXCLUSIVE

2022-05-10T01:20:45Z

Let's test that __HAVE_ARCH_PTE_SWP_EXCLUSIVE works as expected. Link: https://lkml.kernel.org/r/20220329164329.208407-3-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Vlastimil Babka Cc: Andrea Arcangeli Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Christoph Hellwig Cc: Dave Hansen Cc: Don Dutile Cc: Gerald Schaefer Cc: Heiko Carstens Cc: Hugh Dickins Cc: Ingo Molnar Cc: Jan Kara Cc: Jann Horn Cc: Jason Gunthorpe Cc: John Hubbard Cc: "Kirill A. Shutemov" Cc: Liang Zhang Cc: Matthew Wilcox (Oracle) Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Kravetz Cc: Mike Rapoport Cc: Nadav Amit Cc: Oded Gabbay Cc: Oleg Nesterov Cc: Paul Mackerras Cc: Pedro Demarchi Gomes Cc: Peter Xu Cc: Rik van Riel Cc: Roman Gushchin Cc: Shakeel Butt Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Will Deacon Signed-off-by: Andrew Morton

mm/debug_vm_pgtable: drop protection_map[] usage

2022-04-29T06:16:12Z

Patch series "mm: protection_map[] cleanups". This patch (of 2): Although protection_map[] contains the platform defined page protection map for a given vm_flags combination, vm_get_page_prot() is the right interface to use. This will also reduce dependency on protection_map[] which is going to be dropped off completely later on. Link: https://lkml.kernel.org/r/20220404031840.588321-1-anshuman.khandual@arm.com Link: https://lkml.kernel.org/r/20220404031840.588321-2-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual Reviewed-by: Christoph Hellwig Signed-off-by: Andrew Morton

mm/debug_vm_pgtable: remove pte entry from the page table

2022-02-04T17:25:04Z

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

mm: ptep_clear() page table helper

2022-01-15T14:30:28Z

We have ptep_get_and_clear() and ptep_get_and_clear_full() helpers to clear PTE from user page tables, but there is no variant for simple clear of a present PTE from user page tables without using a low level pte_clear() which can be either native or para-virtualised. Add a new ptep_clear() that can be used in common code to clear PTEs from page table. We will need this call later in order to add a hook for page table check. Link: https://lkml.kernel.org/r/20211221154650.1047963-3-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin Cc: Aneesh Kumar K.V Cc: Dave Hansen Cc: David Rientjes Cc: Frederic Weisbecker Cc: Greg Thelen Cc: "H. Peter Anvin" Cc: Hugh Dickins Cc: Ingo Molnar Cc: Jiri Slaby Cc: Jonathan Corbet Cc: Kees Cook Cc: Masahiro Yamada Cc: Mike Rapoport Cc: Muchun Song Cc: Paul Turner Cc: Peter Zijlstra Cc: Sami Tolvanen Cc: Thomas Gleixner Cc: Wei Xu Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds