kernel/linux.git/mm/debug_vm_pgtable.c, branch v6.19.11

mm: softdirty: add pgtable_supports_soft_dirty()

2025-11-24T23:08:54+00:00

Patch series "mm: Add soft-dirty and uffd-wp support for RISC-V", v15. This patchset adds support for Svrsw60t59b [1] extension which is ratified now, also add soft dirty and userfaultfd write protect tracking for RISC-V. The patches 1 and 2 add macros to allow architectures to define their own checks if the soft-dirty / uffd_wp PTE bits are available, in other words for RISC-V, the Svrsw60t59b extension is supported on which device the kernel is running. Also patch1-2 are removing "ifdef CONFIG_MEM_SOFT_DIRTY" "ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP" and "ifdef CONFIG_PTE_MARKER_UFFD_WP" in favor of checks which if not overridden by the architecture, no change in behavior is expected. This patchset has been tested with kselftest mm suite in which soft-dirty, madv_populate, test_unmerge_uffd_wp, and uffd-unit-tests run and pass, and no regressions are observed in any of the other tests. This patch (of 6): Some platforms can customize the PTE PMD entry soft-dirty bit making it unavailable even if the architecture provides the resource. Add an API which architectures can define their specific implementations to detect if soft-dirty bit is available on which device the kernel is running. This patch is removing "ifdef CONFIG_MEM_SOFT_DIRTY" in favor of pgtable_supports_soft_dirty() checks that defaults to IS_ENABLED(CONFIG_MEM_SOFT_DIRTY), if not overridden by the architecture, no change in behavior is expected. We make sure to never set VM_SOFTDIRTY if !pgtable_supports_soft_dirty(), so we will never run into VM_SOFTDIRTY checks. [lorenzo.stoakes@oracle.com: fix VMA selftests] Link: https://lkml.kernel.org/r/dac6ddfe-773a-43d5-8f69-021b9ca4d24b@lucifer.local Link: https://lkml.kernel.org/r/20251113072806.795029-1-zhangchunyan@iscas.ac.cn Link: https://lkml.kernel.org/r/20251113072806.795029-2-zhangchunyan@iscas.ac.cn Link: https://github.com/riscv-non-isa/riscv-iommu/pull/543 [1] Signed-off-by: Chunyan Zhang Acked-by: David Hildenbrand Cc: Albert Ou Cc: Alexandre Ghiti Cc: Al Viro Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Christian Brauner Cc: Conor Dooley Cc: Deepak Gupta Cc: Jan Kara Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Xu Cc: Rob Herring Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Yuanchu Xie Cc: Alexandre Ghiti Cc: Andrew Jones Cc: Conor Dooley Signed-off-by: Andrew Morton

mm: replace remaining pte_to_swp_entry() with softleaf_from_pte()

2025-11-24T23:08:52+00:00

There are straggler invocations of pte_to_swp_entry() lying around, replace all of these with the software leaf entry equivalent - softleaf_from_pte(). With those removed, eliminate pte_to_swp_entry() altogether. No functional change intended. Link: https://lkml.kernel.org/r/d8ee5ccefe4c42d7c4fe1a2e46f285ac40421cd3.1762812360.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Cc: Alexander Gordeev Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Byungchul Park Cc: Chengming Zhou Cc: Chris Li Cc: Christian Borntraeger Cc: Christian Brauner Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: Dev Jain Cc: Gerald Schaefer Cc: Gregory Price Cc: Heiko Carstens Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Jan Kara Cc: Jann Horn Cc: Janosch Frank Cc: Jason Gunthorpe Cc: Joshua Hahn Cc: Kairui Song Cc: Kemeng Shi Cc: Lance Yang Cc: Leon Romanovsky Cc: Liam Howlett Cc: Mathew Brost Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Naoya Horiguchi Cc: Nhat Pham Cc: Nico Pache Cc: Oscar Salvador Cc: Pasha Tatashin Cc: Peter Xu Cc: Rakie Kim Cc: Rik van Riel Cc: Ryan Roberts Cc: SeongJae Park Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: Wei Xu Cc: xu xin Cc: Yuanchu Xie Cc: Zi Yan Signed-off-by: Andrew Morton

mm: eliminate further swapops predicates

2025-11-24T23:08:52+00:00

Having converted so much of the code base to software leaf entries, we can mop up some remaining cases. We replace is_pfn_swap_entry(), pfn_swap_entry_to_page(), is_writable_device_private_entry(), is_device_exclusive_entry(), is_migration_entry(), is_writable_migration_entry(), is_readable_migration_entry(), swp_offset_pfn() and pfn_swap_entry_folio() with softleaf equivalents. No functional change intended. Link: https://lkml.kernel.org/r/956bc9c031604811c0070d2f4bf2f1373f230213.1762812360.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Cc: Alexander Gordeev Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Byungchul Park Cc: Chengming Zhou Cc: Chris Li Cc: Christian Borntraeger Cc: Christian Brauner Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: Dev Jain Cc: Gerald Schaefer Cc: Gregory Price Cc: Heiko Carstens Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Jan Kara Cc: Jann Horn Cc: Janosch Frank Cc: Jason Gunthorpe Cc: Joshua Hahn Cc: Kairui Song Cc: Kemeng Shi Cc: Lance Yang Cc: Leon Romanovsky Cc: Liam Howlett Cc: Mathew Brost Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Naoya Horiguchi Cc: Nhat Pham Cc: Nico Pache Cc: Oscar Salvador Cc: Pasha Tatashin Cc: Peter Xu Cc: Rakie Kim Cc: Rik van Riel Cc: Ryan Roberts Cc: SeongJae Park Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: Wei Xu Cc: xu xin Cc: Yuanchu Xie Cc: Zi Yan Signed-off-by: Andrew Morton

mm: remove remaining is_swap_pmd() users and is_swap_pmd()

2025-11-24T23:08:51+00:00

Update copy_huge_pmd() and change_huge_pmd() to use pmd_is_valid_softleaf() - as this checks for the only valid non-present huge PMD states. Also update mm/debug_vm_pgtable.c to explicitly test for a valid leaf PMD entry (which it was not before, which was incorrect), and have it test against pmd_is_huge() and pmd_is_valid_softleaf() rather than is_swap_pmd(). With these changes done there are no further users of is_swap_pmd(), so remove it. Link: https://lkml.kernel.org/r/1628b00b00c8498bbd2c20b82117ee87845fb738.1762812360.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Cc: Alexander Gordeev Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Byungchul Park Cc: Chengming Zhou Cc: Chris Li Cc: Christian Borntraeger Cc: Christian Brauner Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: Dev Jain Cc: Gerald Schaefer Cc: Gregory Price Cc: Heiko Carstens Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Jan Kara Cc: Jann Horn Cc: Janosch Frank Cc: Jason Gunthorpe Cc: Joshua Hahn Cc: Kairui Song Cc: Kemeng Shi Cc: Lance Yang Cc: Leon Romanovsky Cc: Liam Howlett Cc: Mathew Brost Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Naoya Horiguchi Cc: Nhat Pham Cc: Nico Pache Cc: Oscar Salvador Cc: Pasha Tatashin Cc: Peter Xu Cc: Rakie Kim Cc: Rik van Riel Cc: Ryan Roberts Cc: SeongJae Park Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: Wei Xu Cc: xu xin Cc: Yuanchu Xie Cc: Zi Yan Signed-off-by: Andrew Morton

mm: use leaf entries in debug pgtable + remove is_swap_pte()

2025-11-24T23:08:50+00:00

Remove invocations of is_swap_pte() in mm/debug_vm_pgtable.c and use softleaf_from_pte() and softleaf_is_swap() as necessary to replace this usage. We update the test code to use a 'true' swap entry throughout so we are guaranteed this is not a non-swap entry, so all asserts continue to operate correctly. With this change in place, we no longer use is_swap_pte() anywhere, so remove it. Link: https://lkml.kernel.org/r/222f352e7a99191b4bdfa77e835f2fc0dd83fa72.1762812360.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Vlastimil Babka Cc: Alexander Gordeev Cc: Alistair Popple Cc: Al Viro Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Byungchul Park Cc: Chengming Zhou Cc: Chris Li Cc: Christian Borntraeger Cc: Christian Brauner Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: Dev Jain Cc: Gerald Schaefer Cc: Gregory Price Cc: Heiko Carstens Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Jan Kara Cc: Jann Horn Cc: Janosch Frank Cc: Jason Gunthorpe Cc: Joshua Hahn Cc: Kairui Song Cc: Kemeng Shi Cc: Lance Yang Cc: Leon Romanovsky Cc: Liam Howlett Cc: Mathew Brost Cc: Matthew Wilcox (Oracle) Cc: Miaohe Lin Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Naoya Horiguchi Cc: Nhat Pham Cc: Nico Pache Cc: Oscar Salvador Cc: Pasha Tatashin Cc: Peter Xu Cc: Rakie Kim Cc: Rik van Riel Cc: Ryan Roberts Cc: SeongJae Park Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Vasily Gorbik Cc: Wei Xu Cc: xu xin Cc: Yuanchu Xie Cc: Zi Yan Signed-off-by: Andrew Morton

treewide: include linux/pgalloc.h instead of asm/pgalloc.h

2025-11-17T01:28:25+00:00

For now, including instead of is technically fine unless the .c file calls p*d_populate_kernel() helper functions. But it is a better practice to always include . Include instead of outside arch/. Link: https://lkml.kernel.org/r/20251024113047.119058-3-harry.yoo@oracle.com Signed-off-by: Harry Yoo Acked-by: David Hildenbrand Reviewed-by: Lorenzo Stoakes Reviewed-by: Mike Rapoport (Microsoft) Cc: Liam Howlett Cc: Michal Hocko Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: SeongJae Park Signed-off-by: Andrew Morton

mm/debug_vm_pgtable: add [pte|pmd]_mkwrite_novma() tests

2025-11-17T01:28:18+00:00

Add some [pte|pmd]_mkwrite_novma() relevant tests. [anshuman.khandual@arm.com: add a new test combination per Huang Ying] Link: https://lkml.kernel.org/r/20251024013137.136926-1-anshuman.khandual@arm.com Link: https://lkml.kernel.org/r/20251022032951.3498553-1-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual Suggested-by: Catalin Marinas Reviewed-by: Catalin Marinas Reviewed-by: Huang Ying Acked-by: David Hildenbrand Signed-off-by: Andrew Morton

mm/debug_vm_pgtable: clear page table entries at destroy_args()

2025-08-19T23:35:54+00:00

The mm/debug_vm_pagetable test allocates manually page table entries for the tests it runs, using also its manually allocated mm_struct. That in itself is ok, but when it exits, at destroy_args() it fails to clear those entries with the *_clear functions. The problem is that leaves stale entries. If another process allocates an mm_struct with a pgd at the same address, it may end up running into the stale entry. This is happening in practice on a debug kernel with CONFIG_DEBUG_VM_PGTABLE=y, for example this is the output with some extra debugging I added (it prints a warning trace if pgtables_bytes goes negative, in addition to the warning at check_mm() function): [ 2.539353] debug_vm_pgtable: [get_random_vaddr ]: random_vaddr is 0x7ea247140000 [ 2.539366] kmem_cache info [ 2.539374] kmem_cachep 0x000000002ce82385 - freelist 0x0000000000000000 - offset 0x508 [ 2.539447] debug_vm_pgtable: [init_args ]: args->mm is 0x000000002267cc9e (...) [ 2.552800] WARNING: CPU: 5 PID: 116 at include/linux/mm.h:2841 free_pud_range+0x8bc/0x8d0 [ 2.552816] Modules linked in: [ 2.552843] CPU: 5 UID: 0 PID: 116 Comm: modprobe Not tainted 6.12.0-105.debug_vm2.el10.ppc64le+debug #1 VOLUNTARY [ 2.552859] Hardware name: IBM,9009-41A POWER9 (architected) 0x4e0202 0xf000005 of:IBM,FW910.00 (VL910_062) hv:phyp pSeries [ 2.552872] NIP: c0000000007eef3c LR: c0000000007eef30 CTR: c0000000003d8c90 [ 2.552885] REGS: c0000000622e73b0 TRAP: 0700 Not tainted (6.12.0-105.debug_vm2.el10.ppc64le+debug) [ 2.552899] MSR: 800000000282b033 CR: 24002822 XER: 0000000a [ 2.552954] CFAR: c0000000008f03f0 IRQMASK: 0 [ 2.552954] GPR00: c0000000007eef30 c0000000622e7650 c000000002b1ac00 0000000000000001 [ 2.552954] GPR04: 0000000000000008 0000000000000000 c0000000007eef30 ffffffffffffffff [ 2.552954] GPR08: 00000000ffff00f5 0000000000000001 0000000000000048 0000000000004000 [ 2.552954] GPR12: 00000003fa440000 c000000017ffa300 c0000000051d9f80 ffffffffffffffdb [ 2.552954] GPR16: 0000000000000000 0000000000000008 000000000000000a 60000000000000e0 [ 2.552954] GPR20: 4080000000000000 c0000000113af038 00007fffcf130000 0000700000000000 [ 2.552954] GPR24: c000000062a6a000 0000000000000001 8000000062a68000 0000000000000001 [ 2.552954] GPR28: 000000000000000a c000000062ebc600 0000000000002000 c000000062ebc760 [ 2.553170] NIP [c0000000007eef3c] free_pud_range+0x8bc/0x8d0 [ 2.553185] LR [c0000000007eef30] free_pud_range+0x8b0/0x8d0 [ 2.553199] Call Trace: [ 2.553207] [c0000000622e7650] [c0000000007eef30] free_pud_range+0x8b0/0x8d0 (unreliable) [ 2.553229] [c0000000622e7750] [c0000000007f40b4] free_pgd_range+0x284/0x3b0 [ 2.553248] [c0000000622e7800] [c0000000007f4630] free_pgtables+0x450/0x570 [ 2.553274] [c0000000622e78e0] [c0000000008161c0] exit_mmap+0x250/0x650 [ 2.553292] [c0000000622e7a30] [c0000000001b95b8] __mmput+0x98/0x290 [ 2.558344] [c0000000622e7a80] [c0000000001d1018] exit_mm+0x118/0x1b0 [ 2.558361] [c0000000622e7ac0] [c0000000001d141c] do_exit+0x2ec/0x870 [ 2.558376] [c0000000622e7b60] [c0000000001d1ca8] do_group_exit+0x88/0x150 [ 2.558391] [c0000000622e7bb0] [c0000000001d1db8] sys_exit_group+0x48/0x50 [ 2.558407] [c0000000622e7be0] [c00000000003d810] system_call_exception+0x1e0/0x4c0 [ 2.558423] [c0000000622e7e50] [c00000000000d05c] system_call_vectored_common+0x15c/0x2ec (...) [ 2.558892] ---[ end trace 0000000000000000 ]--- [ 2.559022] BUG: Bad rss-counter state mm:000000002267cc9e type:MM_ANONPAGES val:1 [ 2.559037] BUG: non-zero pgtables_bytes on freeing mm: -6144 Here the modprobe process ended up with an allocated mm_struct from the mm_struct slab that was used before by the debug_vm_pgtable test. That is not a problem, since the mm_struct is initialized again etc., however, if it ends up using the same pgd table, it bumps into the old stale entry when clearing/freeing the page table entries, so it tries to free an entry already gone (that one which was allocated by the debug_vm_pgtable test), which also explains the negative pgtables_bytes since it's accounting for not allocated entries in the current process. As far as I looked pgd_{alloc,free} etc. does not clear entries, and clearing of the entries is explicitly done in the free_pgtables-> free_pgd_range->free_p4d_range->free_pud_range->free_pmd_range-> free_pte_range path. However, the debug_vm_pgtable test does not call free_pgtables, since it allocates mm_struct and entries manually for its test and eg. not goes through page faults. So it also should clear manually the entries before exit at destroy_args(). This problem was noticed on a reboot X number of times test being done on a powerpc host, with a debug kernel with CONFIG_DEBUG_VM_PGTABLE enabled. Depends on the system, but on a 100 times reboot loop the problem could manifest once or twice, if a process ends up getting the right mm->pgd entry with the stale entries used by mm/debug_vm_pagetable. After using this patch, I couldn't reproduce/experience the problems anymore. I was able to reproduce the problem as well on latest upstream kernel (6.16). I also modified destroy_args() to use mmput() instead of mmdrop(), there is no reason to hold mm_users reference and not release the mm_struct entirely, and in the output above with my debugging prints I already had patched it to use mmput, it did not fix the problem, but helped in the debugging as well. Link: https://lkml.kernel.org/r/20250731214051.4115182-1-herton@redhat.com Fixes: 3c9b84f044a9 ("mm/debug_vm_pgtable: introduce struct pgtable_debug_args") Signed-off-by: Herton R. Krzesinski Cc: Anshuman Khandual Cc: Christophe Leroy Cc: Gavin Shan Cc: Gerald Schaefer Cc: Signed-off-by: Andrew Morton

mm/debug_vm_pgtable: use a swp_entry_t input value for swap tests

2025-07-13T23:38:21+00:00

The various __pte/pmd_to_swp_entry and __swp_entry_to_pte/pmd helper functions are expected to operate on swap PTE/PMD entries, not on present and mapped entries. Reflect this in the swap tests by using a swp_entry_t as input value, and convert it to a swap PTE/PMD for testing, similar to how it is already done in pte_swap_exclusive_tests(). Move the swap entry creation from there to init_args() and store it in args, so it can also be used in other functions. The pte/pmd_swap_tests() are also changed to compare entries instead of pfn values, again similar to pte_swap_exclusive_tests(). pte/pmd_pfn() helpers are also not expected to operate on swap PTE/PMD entries at all. Also update documentation, to reflect that the helpers operate on swap PTE/PMD entries and not present and mapped entries, and use correct names, i.e. __swp_to_pte/pmd_entry -> __swp_entry_to_pte/pmd. For consistency, also change pte/pmd_swap_soft_dirty_tests() to use args->swp_entry instead of a present and mapped PTE/PMD. Link: https://lore.kernel.org/all/20250623184321.927418-1-gerald.schaefer@linux.ibm.com Link: https://lkml.kernel.org/r/20250630164726.930405-1-gerald.schaefer@linux.ibm.com Signed-off-by: Gerald Schaefer Acked-by: David Hildenbrand Reviewed-by: Anshuman Khandual Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton

mm: remove callers of pfn_t functionality

2025-07-10T05:42:19+00:00

All PFN_* pfn_t flags have been removed. Therefore there is no longer a need for the pfn_t type and all uses can be replaced with normal pfns. Link: https://lkml.kernel.org/r/bbedfa576c9822f8032494efbe43544628698b1f.1750323463.git-series.apopple@nvidia.com Signed-off-by: Alistair Popple Reviewed-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Acked-by: David Hildenbrand Cc: Balbir Singh Cc: Björn Töpel Cc: Björn Töpel Cc: Chunyan Zhang Cc: Dan Williams Cc: Deepak Gupta Cc: Gerald Schaefer Cc: Inki Dae Cc: John Groves Cc: John Hubbard Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Will Deacon Signed-off-by: Andrew Morton