kernel/git/next/linux-next.git/tools/testing/vma/tests, branch master

mm: remove VMA_IO_BIT check in vma[_flags]_is_kernel_owned()

2026-09-21T23:32:57+00:00

We have now made it such that every driver which sets VMA_IO_BIT marks it as kernel-owned. However, vma_flags_is_kernel_owned() currently checks for VMA_IO_BIT. This was a product of drivers previously marking a range as kernel-owned by setting VMA_IO_BIT alone. Fix this by removing the VMA_IO_BIT check in vma_flags_is_kernel_owned(), and update mmap_validate_vma_flags() to use vma_flags_is_kernel_owned() rather than open-coding the VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT check. This change means that vma[_flags]_can_merge() doesn't check VMA_IO_BIT any longer (which is now redundant) as it calls vma_flags_is_kernel_owned(). Now that the predicate means precisely VMA_PFNMAP_BIT or VMA_MIXEDMAP_BIT, also use it at the other sites which open-code that pair, so the intent is stated rather than the flags, with no functional change: zap_special_vma_range() only zaps kernel-owned mappings, as drivers use it to tear down ranges they established themselves. The mprotect() arch PFN modification check applies to kernel-owned mappings, which may map PFNs without struct pages. NUMA balancing skips VM_MIXEDMAP mappings having already excluded VM_IO and VM_PFNMAP mappings via vma_migratable(), so it skips exactly the kernel-owned mappings - say so. Finally, update the VMA userland merge 'special' flag tests to no longer assert that VMA_IO_BIT prevents merge as VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT now suffices. Link: https://lore.kernel.org/20260917-b4-mmap-prepare-vma-flag-sanify-v3-26-4583d8a23bca@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Andrew Morton Cc: Albert Ou Cc: Alexander Gordeev Cc: Alexei Starovoitov Cc: Alistair Popple Cc: Al Viro Cc: Andreas Larsson Cc: Andrii Nakryiko Cc: "Aneesh Kumar K.V" Cc: Anup Patel Cc: Arnaldo Carvalho de Melo Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: "Borislav Petkov (AMD)" Cc: Byungchul Park Cc: Catalin Marinas Cc: Chengming Zhou Cc: Chris Li Cc: Christian Borntraeger Cc: Christian Brauner Cc: Claudio Imbrenda Cc: Dave Airlie Cc: Dave Hansen Cc: David Hildenbrand Cc: David S. Miller Cc: Dennis Dalessandro Cc: Dev Jain Cc: Doug Gilbert Cc: Eduard Zingerman Cc: Emil Tsalapatis Cc: Gerald Schaefer Cc: Greg Kroah-Hartman Cc: Gregory Price Cc: Harry Yoo Cc: Heiko Carstens Cc: Helge Deller Cc: "Huang, Ying" Cc: Ingo Molnar Cc: James Bottomley Cc: Jan Kara Cc: Jann Horn Cc: Janosch Frank Cc: Jaroslav Kysela Cc: Jason Gunthorpe Cc: Jaya Kumar Cc: Johannes Weiner Cc: John Hubbard Cc: Jonathan Corbet Cc: Joshua Hahn Cc: Juri Lelli Cc: Kairui Song Cc: Kemeng Shi Cc: Kiryl Shutsemau Cc: Kumar Kartikeya Dwivedi Cc: Lance Yang Cc: Leon Romanovsky Cc: Liam R. Howlett Cc: Maarten Lankhorst Cc: Madhavan Srinivasan Cc: Marc Rutland Cc: Marc Zyngier Cc: "Masami Hiramatsu (Google)" Cc: Matthew Brost Cc: Matthew Wilcox (Oracle) Cc: Maxime Ripard Cc: Michal Hocko Cc: Michal Hocko Cc: Mike Rapoport Cc: Miklos Szeredi Cc: Muchun Song Cc: Namhyung kim Cc: Nhat Pham Cc: Nicholas Piggin Cc: Oleg Nesterov Cc: Oscar Salvador Cc: Palmer Dabbelt Cc: Paul Moore Cc: Pedro Falcato Cc: Peter Xu Cc: Peter Zijlstra Cc: Rakie Kim Cc: Rik van Riel Cc: Ryan Roberts Cc: Sebastian Reichel Cc: Shakeel Butt Cc: Stephen Smalley Cc: Suren Baghdasaryan Cc: Takashi Iwai (SUSE) Cc: Takashi Iwai Cc: Thomas Zimemrmann Cc: Vasily Gorbik Cc: Vincent Guittot Cc: Vlastimil Babka Cc: Wei Xu Cc: Will Deacon Cc: Yuanchu Xie Cc: Zi Yan

tools/testing/vma: cover hole filling through __mmap_region()

2026-09-21T23:32:30+00:00

The mmap tests extend existing mappings one neighbor at a time, while merge tests construct merge state directly. Neither exercises filling a hole between compatible mappings through the mmap setup and completion path. Fill a gap through __mmap_region() and require both neighbors to merge into one VMA. Repeat with only the new mapping's execute permission set and require three separate VMAs. Check boundaries, permissions, page offsets, map_count and cleanup. Link: https://lore.kernel.org/178886112560.138404.17741948638665342936.vma-v2@tychen.cc Signed-off-by: Tianyi Chen Signed-off-by: Andrew Morton Reviewed-by: Lorenzo Stoakes (ARM) Cc: Jann Horn Cc: Liam R. Howlett Cc: Pedro Falcato Cc: Vlastimil Babka Assisted-by: Codex:GPT-6

tools/testing/vma: add test to assert MAP_PRIVATE-/dev/zero is anon

2026-09-21T23:31:51+00:00

Now we've made MAP_PRIVATE-mapped /dev/zero mappings truly anonymous, add a VMA userland test to assert that this is the case and everything is as we would expect for an anonymous mapping. Link: https://lore.kernel.org/20260908-map-private-dev-zero-v2-5-acc7b5625305@kernel.org Acked-by: David Hildenbrand (Arm) Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Andrew Morton Cc: Arnd Bergmann Cc: Baolin Wang Cc: Greg Kroah-Hartman Cc: Hugh Dickins Cc: Jan Kara Cc: Jann Horn Cc: Liam R. Howlett Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Rapoport (Microsoft) Cc: Pedro Falcato Cc: Suren Baghdasaryan Cc: Vlastimil Babka

mm/mremap: fix locked_vm leak from MREMAP_DONTUNMAP self-merge

2026-09-21T23:30:06+00:00

Patch series "mm/mremap: fix two issues with MREMAP_DONTUNMAP". The MREMAP_DONTUNMAP feature is highly unusual in that it permits mremap() operations that keep the original VMA in place. Historically this has led to a lot of bugs where non-obvious interactions occur between existing mremap() operations and the original VMA. Commit 397432cab17b ("mm/mremap: account mm->locked_vm correctly for MREMAP_DONTUNMAP") fixed an accidentally introduced bug around mm->locked_vm accounting, but this wasn't the only issue. And thus history repeats itself, as it turns out that mm->locked_vm accounting is broken by MREMAP_DONTUNMAP yet again by two further cases, and has been broken ever since the feature was introduced. Both relate to the fact that VMA_LOCKED_BIT is cleared on the source VMA (it has to be as all page tables are moved): 1. If an unfaulted VMA_LOCKONFAULT_BIT anonymous VMA self-merges it clears the VMA_LOCKED_BIT flag and permanently leaks mm->locked_vm pages. 2. If a partial mremap() is performed on a locked VMA there is a leak equal to the number of pages not copied. (Both for MREMAP_DONTUNMAP operations only) Both issues can be fixed by treating the source range as distinct from the destination range, which is the definition of what MREMAP_DONTUNMAP does so is appropriate. In case 1, simply disallow the self-merge, keeping adjacent source and destination VMAs distinct. In case 2, split the source range ahead of time, so accounting is always correct. Both changes were tested locally and confirmed to fix the issues. For the purposes of a backport, the fixes are kept distinct, a follow-up series can add self-tests. This patch (of 2): The MREMAP_DONTUNMAP feature is highly unusual in that it permits mremap() operations that keep the original VMA in place. Historically this has led to a lot of bugs where non-obvious interactions occur between existing mremap() operations and the original VMA. Fix another of these - self-merge. Self-merge occurs when a VMA is moved in front of or behind itself and the attributes of the VMA permit such a merge. Practically this can only happen for unfaulted anonymous VMAs due to the page offset equality requirement for merge: |------------| | | | v |...........||-----------||...........| | || unfaulted || | |...........||-----------||...........| ^ | | | |------------| This becomes problematic if the VMA is configured by the user to mlock-on-fault, i.e. the VMA_LOCKED_BIT, VMA_LOCKONFAULT_BIT VMA flags are set. MREMAP_DONTUNMAP clears mlock flags for the source VMA and maintains them for the destination VMA. Self-merge makes this impossible (there is only one VMA) and incorrectly clears the destination VMA's mlock flags. This causes a leak in mm->locked_vm as clearing this flag does not decrement the counter and the VMA no longer has VMA_LOCKED_BIT set so it is not decremented on unmap. Resolve this by simply disallowing a self-merge in this case - the source and destination VMAs are kept distinct and then are able to have distinct mlock() flags. Update dontunmap_complete() to make the now-redundant self-merge check a VM_WARN_ON_ONCE() instead to guard against future regressions. Also update the VMA userland tests to reflect the change. Link: https://lore.kernel.org/20260920-fix-dontunmap-partial-self-merge-v1-0-6ffb556f8f8b@kernel.org Link: https://lore.kernel.org/20260920-fix-dontunmap-partial-self-merge-v1-1-6ffb556f8f8b@kernel.org Fixes: e346b3813067 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()") Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Andrew Morton Cc: Brian Geffon Cc: Jann Horn Cc: Kirill A. Shutemov Cc: Liam Howlett Cc: Minchan Kim Cc: Pedro Falcato Cc: "Vlastimil Babka (SUSE)" Cc:

tools/testing/vma: expand VMA merge tests to assert anon pgoff

2026-08-25T01:42:53+00:00

Now we have introduced the VMA anonymous page offset attribute and update it when VMAs are manipulated, update VMA merge tests to assert that the anonymous page offset is as expected. Also update instances where we could use vma_start_pgoff() to do so. Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-15-c21581c0c3c8@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Acked-by: David Hildenbrand (Arm) Cc: Adrian Hunter Cc: Alexander Deucher Cc: Alexander Gordeev Cc: Alexander Shishkin Cc: Alistair Popple Cc: Arnaldo Carvalho de Melo Cc: Arnd Bergmann Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Boris Brezillon Cc: Byungchul Park Cc: Chengming Zhou Cc: Chris Li Cc: Christan König Cc: Christian Borntraeger Cc: Claudio Imbrenda Cc: Dave Airlie Cc: Dev Jain Cc: Gerald Schaefer Cc: Greg Kroah-Hartman Cc: Gregory Price (Meta) Cc: Harry Yoo Cc: Heiko Carstens Cc: Huang Ray Cc: "Huang, Ying" Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jan Kara Cc: Jann Horn Cc: Janosch Frank Cc: Jason Gunthorpe Cc: Jiri Olsa Cc: John Hubbard Cc: Joshua Hahn Cc: Kairui Song Cc: Kees Cook Cc: Kemeng Shi Cc: Lance Yang Cc: Liam R. Howlett Cc: Liviu Dudau Cc: Maarten Lankhorst Cc: Marc Rutland Cc: "Masami Hiramatsu (Google)" Cc: Matthew Auld Cc: Matthew Brost Cc: Matthew Wilcox (Oracle) Cc: Maxime Ripard Cc: Miaohe Lin Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Namhyung kim Cc: Naoya Horiguchi Cc: Nhat Pham Cc: Nico Pache Cc: Oleg Nesterov Cc: Oscar Salvador Cc: Pedro Falcato Cc: Peter Xu Cc: Peter Zijlstra Cc: Rakie Kim Cc: Rik van Riel Cc: Rodrigo Vivi Cc: Ryan Roberts Cc: Steven Price Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Thomas Hellström Cc: Thomas Zimemrmann Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: xu xin Cc: Zi Yan Signed-off-by: Andrew Morton

mm: propagate VMA anonymous page offset on map, remap, split + merge

2026-08-25T01:42:52+00:00

We must correctly update VMA anonymous page offset state on all VMA operations that would result in it changing, with special attention given to remapping. We cover most cases by simply updating vma_set_range() to do so (with a new anonymous page offset parameter), but also notably must update the merging and mapping logic to propagate this parameter correctly. The remap logic remains the same - we may update the anonymous page offset if the VMA is unfaulted, but now this applies to MAP_PRIVATE file-backed mappings too, so we update the code to reflect this. Note that we use __linear_anon_page_index() upon remap as the VMA may be shared, in order that we update the field consistently regardless of VMA type. Similarly, pass through anon page offset to the merge logic, updating the vma_merge_struct struct to propagate it, and also use __linear_anon_page_index() to obtain the anonymous page index so it can be safely used for both shared and MAP_PRIVATE file-backed mappings. In copy_vma(), the anonymous page offset is updated regardless of whether the mapping is a CoW mapping or not. This is both to keep the anonymous page offset consistent even for non-CoW mappings (it is set so should at least remain correct) and makes the logic cleaner. A self-merge however remains permitted only for mappings which can have a populated vma->anon_vma and do not require alignment on a separate file offset - that is pure anonymous VMAs, so only set can_self_merge if vma_is_anonymous(). Finally, we update insert_vm_struct() to correctly set the anonymous page offset on insertion of a VMA. We simply ensure state is correctly propagated here, so no functional changes are intended. Also update VMA userland tests to reflect this change. Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-9-c21581c0c3c8@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Acked-by: David Hildenbrand (Arm) Cc: Adrian Hunter Cc: Alexander Deucher Cc: Alexander Gordeev Cc: Alexander Shishkin Cc: Alistair Popple Cc: Arnaldo Carvalho de Melo Cc: Arnd Bergmann Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Boris Brezillon Cc: Byungchul Park Cc: Chengming Zhou Cc: Chris Li Cc: Christan König Cc: Christian Borntraeger Cc: Claudio Imbrenda Cc: Dave Airlie Cc: Dev Jain Cc: Gerald Schaefer Cc: Greg Kroah-Hartman Cc: Gregory Price (Meta) Cc: Harry Yoo Cc: Heiko Carstens Cc: Huang Ray Cc: "Huang, Ying" Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jan Kara Cc: Jann Horn Cc: Janosch Frank Cc: Jason Gunthorpe Cc: Jiri Olsa Cc: John Hubbard Cc: Joshua Hahn Cc: Kairui Song Cc: Kees Cook Cc: Kemeng Shi Cc: Lance Yang Cc: Liam R. Howlett Cc: Liviu Dudau Cc: Maarten Lankhorst Cc: Marc Rutland Cc: "Masami Hiramatsu (Google)" Cc: Matthew Auld Cc: Matthew Brost Cc: Matthew Wilcox (Oracle) Cc: Maxime Ripard Cc: Miaohe Lin Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Namhyung kim Cc: Naoya Horiguchi Cc: Nhat Pham Cc: Nico Pache Cc: Oleg Nesterov Cc: Oscar Salvador Cc: Pedro Falcato Cc: Peter Xu Cc: Peter Zijlstra Cc: Rakie Kim Cc: Rik van Riel Cc: Rodrigo Vivi Cc: Ryan Roberts Cc: Steven Price Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Thomas Hellström Cc: Thomas Zimemrmann Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: xu xin Cc: Zi Yan Signed-off-by: Andrew Morton

tools/testing/vma: add tests for copy_vma() self-merge

2026-08-25T01:42:51+00:00

Assert that a VMA can be moved backwards, forwards and between a preceding VMA and its old self. In the cases in which the VMA merges only with itself expect that to be achieved by expanding its old self, so assert that these function correctly. However in the case of a merge between a preceding VMA and itself the original VMA is removed, so assert that the preceding VMA replaces the one passed in as vmap and the merge is as expected. Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-8-c21581c0c3c8@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Acked-by: David Hildenbrand (Arm) Cc: Adrian Hunter Cc: Alexander Deucher Cc: Alexander Gordeev Cc: Alexander Shishkin Cc: Alistair Popple Cc: Arnaldo Carvalho de Melo Cc: Arnd Bergmann Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Boris Brezillon Cc: Byungchul Park Cc: Chengming Zhou Cc: Chris Li Cc: Christan König Cc: Christian Borntraeger Cc: Claudio Imbrenda Cc: Dave Airlie Cc: Dev Jain Cc: Gerald Schaefer Cc: Greg Kroah-Hartman Cc: Gregory Price (Meta) Cc: Harry Yoo Cc: Heiko Carstens Cc: Huang Ray Cc: "Huang, Ying" Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jan Kara Cc: Jann Horn Cc: Janosch Frank Cc: Jason Gunthorpe Cc: Jiri Olsa Cc: John Hubbard Cc: Joshua Hahn Cc: Kairui Song Cc: Kees Cook Cc: Kemeng Shi Cc: Lance Yang Cc: Liam R. Howlett Cc: Liviu Dudau Cc: Maarten Lankhorst Cc: Marc Rutland Cc: "Masami Hiramatsu (Google)" Cc: Matthew Auld Cc: Matthew Brost Cc: Matthew Wilcox (Oracle) Cc: Maxime Ripard Cc: Miaohe Lin Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Namhyung kim Cc: Naoya Horiguchi Cc: Nhat Pham Cc: Nico Pache Cc: Oleg Nesterov Cc: Oscar Salvador Cc: Pedro Falcato Cc: Peter Xu Cc: Peter Zijlstra Cc: Rakie Kim Cc: Rik van Riel Cc: Rodrigo Vivi Cc: Ryan Roberts Cc: Steven Price Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Thomas Hellström Cc: Thomas Zimemrmann Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: xu xin Cc: Zi Yan Signed-off-by: Andrew Morton

mm/vma: update vma_shrink() to not pass start, pgoff parameters

2026-08-05T02:19:03+00:00

vma_shrink() is only used by relocate_vma_down() to shrink the tail of a VMA. Therefore neither the start nor the pgoff parameters make any sense. It seemed we were passing the pgoff parameter solely to satisfy vma_set_range()'s requirement for pgoff being specified. Since vma_set_range() is now isolated to vma.c, we can simply introduce __vma_set_range() which sets only vma->vm_[start, end], and invoke this instead, removing start and pgoff from vma_shrink() altogether. No functional change intended. Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-26-2a5aa403d977@kernel.org Signed-off-by: Lorenzo Stoakes Reviewed-by: Pedro Falcato Reviewed-by: Gregory Price Reviewed-by: Vlastimil Babka (SUSE) Cc: Ackerley Tng Cc: David Hildenbrand (Arm) Cc: Kai Huang Cc: Marek Szyprowski Cc: SJ Park Cc: Thomas Zimmermann Cc: Liam R. Howlett (Oracle) Cc: Zi Yan Signed-off-by: Andrew Morton

tools/testing/vma: use vma_start_pgoff() in merge tests

2026-08-05T02:18:56+00:00

Now we have the vma_start_pgoff() helper, update the merge tests to make use of it for consistency. No functional change intended. Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-3-2a5aa403d977@kernel.org Signed-off-by: Lorenzo Stoakes Reviewed-by: Pedro Falcato Reviewed-by: Gregory Price Reviewed-by: Vlastimil Babka (SUSE) Reviewed-by: Liam R. Howlett (Oracle) Reviewed-by: Zi Yan Cc: Ackerley Tng Cc: David Hildenbrand (Arm) Cc: Kai Huang Cc: Marek Szyprowski Cc: SJ Park Cc: Thomas Zimmermann Signed-off-by: Andrew Morton

mm/vma: convert __mmap_region() to use vma_flags_t

2026-04-05T20:53:41+00:00

Update the mmap() implementation logic implemented in __mmap_region() and functions invoked by it. The mmap_region() function converts its input vm_flags_t parameter to a vma_flags_t value which it then passes to __mmap_region() which uses the vma_flags_t value consistently from then on. As part of the change, we convert map_deny_write_exec() to using vma_flags_t (it was incorrectly using unsigned long before), and place it in vma.h, as it is only used internal to mm. With this change, we eliminate the legacy is_shared_maywrite_vm_flags() helper function which is now no longer required. We are also able to update the MMAP_STATE() and VMG_MMAP_STATE() macros to use the vma_flags_t value. Finally, we update the VMA tests to reflect the change. Link: https://lkml.kernel.org/r/1fc33a404c962f02da778da100387cc19bd62153.1774034900.git.ljs@kernel.org Signed-off-by: Lorenzo Stoakes (Oracle) Acked-by: Vlastimil Babka (SUSE) Cc: Albert Ou Cc: Alexander Gordeev Cc: Alexandre Ghiti Cc: Al Viro Cc: Anton Ivanov Cc: "Borislav Petkov (AMD)" Cc: Catalin Marinas Cc: Chengming Zhou Cc: Christian Borntraeger Cc: Christian Brauner Cc: David Hildenbrand Cc: Dinh Nguyen Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Huacai Chen Cc: Ingo Molnar Cc: Jan Kara Cc: Jann Horn Cc: Johannes Berg Cc: Kees Cook Cc: Liam Howlett Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Ondrej Mosnacek Cc: Palmer Dabbelt Cc: Paul Moore Cc: Pedro Falcato Cc: Richard Weinberger Cc: Russell King Cc: Stephen Smalley Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Thomas Bogendoerfer Cc: Vasily Gorbik Cc: Vineet Gupta Cc: WANG Xuerui Cc: Will Deacon Cc: xu xin Signed-off-by: Andrew Morton