kernel/linux.git/mm/vma.c, branch v6.18.22

mm/vma: enforce VMA fork limit on unfaulted,faulted mremap merge too

2026-01-30T09:32:28+00:00

[ Upstream commit 3b617fd3d317bf9dd7e2c233e56eafef05734c9d ] The is_mergeable_anon_vma() function uses vmg->middle as the source VMA. However when merging a new VMA, this field is NULL. In all cases except mremap(), the new VMA will either be newly established and thus lack an anon_vma, or will be an expansion of an existing VMA thus we do not care about whether VMA is CoW'd or not. In the case of an mremap(), we can end up in a situation where we can accidentally allow an unfaulted/faulted merge with a VMA that has been forked, violating the general rule that we do not permit this for reasons of anon_vma lock scalability. Now we have the ability to be aware of the fact we are copying a VMA and also know which VMA that is, we can explicitly check for this, so do so. This is pertinent since commit 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA merges"), as this patch permits unfaulted/faulted merges that were previously disallowed running afoul of this issue. While we are here, vma_had_uncowed_parents() is a confusing name, so make it simple and rename it to vma_is_fork_child(). Link: https://lkml.kernel.org/r/6e2b9b3024ae1220961c8b81d74296d4720eaf2b.1767638272.git.lorenzo.stoakes@oracle.com Fixes: 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA merges") Signed-off-by: Lorenzo Stoakes Reviewed-by: Harry Yoo Reviewed-by: Jeongjun Park Acked-by: Vlastimil Babka Cc: David Hildenbrand (Red Hat) Cc: Jann Horn Cc: Liam Howlett Cc: Pedro Falcato Cc: Rik van Riel Cc: Yeoreum Yun Cc: Signed-off-by: Andrew Morton [ with upstream commit 61f67c230a5e backported, this simply applied correctly. Built + tested ] Signed-off-by: Lorenzo Stoakes Signed-off-by: Greg Kroah-Hartman

mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted merge

2026-01-30T09:32:28+00:00

[ upstream commit 61f67c230a5e7c741c352349ea80147fbe65bfae ] Patch series "mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted merge", v2. Commit 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA merges") introduced the ability to merge previously unavailable VMA merge scenarios. However, it is handling merges incorrectly when it comes to mremap() of a faulted VMA adjacent to an unfaulted VMA. The issues arise in three cases: 1. Previous VMA unfaulted: copied -----| v |-----------|.............| | unfaulted |(faulted VMA)| |-----------|.............| prev 2. Next VMA unfaulted: copied -----| v |.............|-----------| |(faulted VMA)| unfaulted | |.............|-----------| next 3. Both adjacent VMAs unfaulted: copied -----| v |-----------|.............|-----------| | unfaulted |(faulted VMA)| unfaulted | |-----------|.............|-----------| prev next This series fixes each of these cases, and introduces self tests to assert that the issues are corrected. I also test a further case which was already handled, to assert that my changes continues to correctly handle it: 4. prev unfaulted, next faulted: copied -----| v |-----------|.............|-----------| | unfaulted |(faulted VMA)| faulted | |-----------|.............|-----------| prev next This bug was discovered via a syzbot report, linked to in the first patch in the series, I confirmed that this series fixes the bug. I also discovered that we are failing to check that the faulted VMA was not forked when merging a copied VMA in cases 1-3 above, an issue this series also addresses. I also added self tests to assert that this is resolved (and confirmed that the tests failed prior to this). I also cleaned up vma_expand() as part of this work, renamed vma_had_uncowed_parents() to vma_is_fork_child() as the previous name was unduly confusing, and simplified the comments around this function. This patch (of 4): Commit 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA merges") introduced the ability to merge previously unavailable VMA merge scenarios. The key piece of logic introduced was the ability to merge a faulted VMA immediately next to an unfaulted VMA, which relies upon dup_anon_vma() to correctly handle anon_vma state. In the case of the merge of an existing VMA (that is changing properties of a VMA and then merging if those properties are shared by adjacent VMAs), dup_anon_vma() is invoked correctly. However in the case of the merge of a new VMA, a corner case peculiar to mremap() was missed. The issue is that vma_expand() only performs dup_anon_vma() if the target (the VMA that will ultimately become the merged VMA): is not the next VMA, i.e. the one that appears after the range in which the new VMA is to be established. A key insight here is that in all other cases other than mremap(), a new VMA merge either expands an existing VMA, meaning that the target VMA will be that VMA, or would have anon_vma be NULL. Specifically: * __mmap_region() - no anon_vma in place, initial mapping. * do_brk_flags() - expanding an existing VMA. * vma_merge_extend() - expanding an existing VMA. * relocate_vma_down() - no anon_vma in place, initial mapping. In addition, we are in the unique situation of needing to duplicate anon_vma state from a VMA that is neither the previous or next VMA being merged with. dup_anon_vma() deals exclusively with the target=unfaulted, src=faulted case. This leaves four possibilities, in each case where the copied VMA is faulted: 1. Previous VMA unfaulted: copied -----| v |-----------|.............| | unfaulted |(faulted VMA)| |-----------|.............| prev target = prev, expand prev to cover. 2. Next VMA unfaulted: copied -----| v |.............|-----------| |(faulted VMA)| unfaulted | |.............|-----------| next target = next, expand next to cover. 3. Both adjacent VMAs unfaulted: copied -----| v |-----------|.............|-----------| | unfaulted |(faulted VMA)| unfaulted | |-----------|.............|-----------| prev next target = prev, expand prev to cover. 4. prev unfaulted, next faulted: copied -----| v |-----------|.............|-----------| | unfaulted |(faulted VMA)| faulted | |-----------|.............|-----------| prev next target = prev, expand prev to cover. Essentially equivalent to 3, but with additional requirement that next's anon_vma is the same as the copied VMA's. This is covered by the existing logic. To account for this very explicitly, we introduce vma_merge_copied_range(), which sets a newly introduced vmg->copied_from field, then invokes vma_merge_new_range() which handles the rest of the logic. We then update the key vma_expand() function to clean up the logic and make what's going on clearer, making the 'remove next' case less special, before invoking dup_anon_vma() unconditionally should we be copying from a VMA. Note that in case 3, the if (remove_next) ... branch will be a no-op, as next=src in this instance and src is unfaulted. In case 4, it won't be, but since in this instance next=src and it is faulted, this will have required tgt=faulted, src=faulted to be compatible, meaning that next->anon_vma == vmg->copied_from->anon_vma, and thus a single dup_anon_vma() of next suffices to copy anon_vma state for the copied-from VMA also. If we are copying from a VMA in a successful merge we must _always_ propagate anon_vma state. This issue can be observed most directly by invoked mremap() to move around a VMA and cause this kind of merge with the MREMAP_DONTUNMAP flag specified. This will result in unlink_anon_vmas() being called after failing to duplicate anon_vma state to the target VMA, which results in the anon_vma itself being freed with folios still possessing dangling pointers to the anon_vma and thus a use-after-free bug. This bug was discovered via a syzbot report, which this patch resolves. We further make a change to update the mergeable anon_vma check to assert the copied-from anon_vma did not have CoW parents, as otherwise dup_anon_vma() might incorrectly propagate CoW ancestors from the next VMA in case 4 despite the anon_vma's being identical for both VMAs. Link: https://lkml.kernel.org/r/cover.1767638272.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/b7930ad2b1503a657e29fe928eb33061d7eadf5b.1767638272.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Fixes: 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA merges") Reported-by: syzbot+b165fc2e11771c66d8ba@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/694a2745.050a0220.19928e.0017.GAE@google.com/ Reported-by: syzbot+5272541ccbbb14e2ec30@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/694e3dc6.050a0220.35954c.0066.GAE@google.com/ Reviewed-by: Harry Yoo Reviewed-by: Jeongjun Park Acked-by: Vlastimil Babka Cc: David Hildenbrand (Red Hat) Cc: Jann Horn Cc: Yeoreum Yun Cc: Liam Howlett Cc: Liam R. Howlett Cc: Pedro Falcato Cc: Rik van Riel Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton [ updated to account for lack of sticky VMA flags + built, tested confirmed working ] Signed-off-by: Lorenzo Stoakes Signed-off-by: Greg Kroah-Hartman

mm: fix some typos in mm module

2026-01-30T09:32:28+00:00

[ Upstream commit b6c46600bfb28b4be4e9cff7bad4f2cf357e0fb7 ] Below are some typos in the code comments: intevals ==> intervals addesses ==> addresses unavaliable ==> unavailable facor ==> factor droping ==> dropping exlusive ==> exclusive decription ==> description confict ==> conflict desriptions ==> descriptions otherwize ==> otherwise vlaue ==> value cheching ==> checking exisitng ==> existing modifed ==> modified differenciate ==> differentiate refernece ==> reference permissons ==> permissions indepdenent ==> independent spliting ==> splitting Just fix it. Link: https://lkml.kernel.org/r/20250929002608.1633825-1-jianyungao89@gmail.com Signed-off-by: jianyun.gao Reviewed-by: SeongJae Park Reviewed-by: Wei Yang Reviewed-by: Dev Jain Reviewed-by: Liam R. Howlett Acked-by: Chris Li Signed-off-by: Andrew Morton Stable-dep-of: 3937027caecb ("mm/hugetlb: fix two comments related to huge_pmd_unshare()") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

mm: specify separate file and vm_file params in vm_area_desc

2025-09-23T03:17:11+00:00

Patch series "mm: do not assume file == vma->vm_file in compat_vma_mmap_prepare()", v2. As part of the efforts to eliminate the problematic f_op->mmap callback, a new callback - f_op->mmap_prepare was provided. While we are converting these callbacks, we must deal with 'stacked' filesystems and drivers - those which in their own f_op->mmap callback invoke an inner f_op->mmap callback. To accomodate for this, a compatibility layer is provided that, via vfs_mmap(), detects if f_op->mmap_prepare is provided and if so, generates a vm_area_desc containing the VMA's metadata and invokes the call. So far, we have provided desc->file equal to vma->vm_file. However this is not necessarily valid, especially in the case of stacked drivers which wish to assign a new file after the inner hook is invoked. To account for this, we adjust vm_area_desc to have both file and vm_file fields. The .vm_file field is strictly set to vma->vm_file (or in the case of a new mapping, what will become vma->vm_file). However, .file is set to whichever file vfs_mmap() is invoked with when using the compatibilty layer. Therefore, if the VMA's file needs to be updated in .mmap_prepare, desc->vm_file should be assigned, whilst desc->file should be read. No current f_op->mmap_prepare users assign desc->file so this is safe to do. This makes the .mmap_prepare callback in the context of a stacked filesystem or driver completely consistent with the existing .mmap implementations. While we're here, we do a few small cleanups, and ensure that we const-ify things correctly in the vm_area_desc struct to avoid hooks accidentally trying to assign fields they should not. This patch (of 2): Stacked filesystems and drivers may invoke mmap hooks with a struct file pointer that differs from the overlying file. We will make this functionality possible in a subsequent patch. In order to prepare for this, let's update vm_area_struct to separately provide desc->file and desc->vm_file parameters. The desc->file parameter is the file that the hook is expected to operate upon, and is not assignable (though the hok may wish to e.g. update the file's accessed time for instance). The desc->vm_file defaults to what will become vma->vm_file and is what the hook must reassign should it wish to change the VMA"s vma->vm_file. For now we keep desc->file, vm_file the same to remain consistent. No f_op->mmap_prepare() callback sets a new vma->vm_file currently, so this is safe to change. While we're here, make the mm_struct desc->mm pointers at immutable as well as the desc->mm field itself. As part of this change, also update the single hook which this would otherwise break - mlock_future_ok(), invoked by secretmem_mmap_prepare()). We additionally update set_vma_from_desc() to compare fields in a more logical fashion, checking the (possibly) user-modified fields as the first operand against the existing value as the second one. Additionally, update VMA tests to accommodate changes. Link: https://lkml.kernel.org/r/cover.1756920635.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/3fa15a861bb7419f033d22970598aa61850ea267.1756920635.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Cc: Al Viro Cc: Christian Brauner Cc: David Hildenbrand Cc: Jan Kara Cc: Jann Horn Cc: Liam Howlett Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Pedro Falcato Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2025-08-03-12-35' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-08-05T13:02:07+00:00

Pull more MM updates from Andrew Morton: "Significant patch series in this pull request: - "mseal cleanups" (Lorenzo Stoakes) Some mseal cleaning with no intended functional change. - "Optimizations for khugepaged" (David Hildenbrand) Improve khugepaged throughput by batching PTE operations for large folios. This gain is mainly for arm64. - "x86: enable EXECMEM_ROX_CACHE for ftrace and kprobes" (Mike Rapoport) A bugfix, additional debug code and cleanups to the execmem code. - "mm/shmem, swap: bugfix and improvement of mTHP swap in" (Kairui Song) Bugfixes, cleanups and performance improvememnts to the mTHP swapin code" * tag 'mm-stable-2025-08-03-12-35' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (38 commits) mm: mempool: fix crash in mempool_free() for zero-minimum pools mm: correct type for vmalloc vm_flags fields mm/shmem, swap: fix major fault counting mm/shmem, swap: rework swap entry and index calculation for large swapin mm/shmem, swap: simplify swapin path and result handling mm/shmem, swap: never use swap cache and readahead for SWP_SYNCHRONOUS_IO mm/shmem, swap: tidy up swap entry splitting mm/shmem, swap: tidy up THP swapin checks mm/shmem, swap: avoid redundant Xarray lookup during swapin x86/ftrace: enable EXECMEM_ROX_CACHE for ftrace allocations x86/kprobes: enable EXECMEM_ROX_CACHE for kprobes allocations execmem: drop writable parameter from execmem_fill_trapping_insns() execmem: add fallback for failures in vmalloc(VM_ALLOW_HUGE_VMAP) execmem: move execmem_force_rw() and execmem_restore_rox() before use execmem: rework execmem_cache_free() execmem: introduce execmem_alloc_rw() execmem: drop unused execmem_update_copy() mm: fix a UAF when vma->mm is freed after vma->vm_refcnt got dropped mm/rmap: add anon_vma lifetime debug check mm: remove mm/io-mapping.c ...

mm/mseal: small cleanups

2025-08-02T19:06:09+00:00

Drop the wholly unnecessary set_vma_sealed() helper(), which is used only once, and place VMA_ITERATOR() declarations in the correct place. Retain vma_is_sealed(), and use it instead of the confusingly named can_modify_vma(), so it's abundantly clear what's being tested, rather then a nebulous sense of 'can the VMA be modified'. No functional change intended. Link: https://lkml.kernel.org/r/98cf28d04583d632a6eb698e9ad23733bb6af26b.1753431105.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Liam R. Howlett Reviewed-by: Pedro Falcato Acked-by: David Hildenbrand Acked-by: Jeff Xu Cc: Jann Horn Cc: Kees Cook Cc: Vlastimil Babka Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-07-31T21:57:54+00:00

Pull MM updates from Andrew Morton: "As usual, many cleanups. The below blurbiage describes 42 patchsets. 21 of those are partially or fully cleanup work. "cleans up", "cleanup", "maintainability", "rationalizes", etc. I never knew the MM code was so dirty. "mm: ksm: prevent KSM from breaking merging of new VMAs" (Lorenzo Stoakes) addresses an issue with KSM's PR_SET_MEMORY_MERGE mode: newly mapped VMAs were not eligible for merging with existing adjacent VMAs. "mm/damon: introduce DAMON_STAT for simple and practical access monitoring" (SeongJae Park) adds a new kernel module which simplifies the setup and usage of DAMON in production environments. "stop passing a writeback_control to swap/shmem writeout" (Christoph Hellwig) is a cleanup to the writeback code which removes a couple of pointers from struct writeback_control. "drivers/base/node.c: optimization and cleanups" (Donet Tom) contains largely uncorrelated cleanups to the NUMA node setup and management code. "mm: userfaultfd: assorted fixes and cleanups" (Tal Zussman) does some maintenance work on the userfaultfd code. "Readahead tweaks for larger folios" (Ryan Roberts) implements some tuneups for pagecache readahead when it is reading into order>0 folios. "selftests/mm: Tweaks to the cow test" (Mark Brown) provides some cleanups and consistency improvements to the selftests code. "Optimize mremap() for large folios" (Dev Jain) does that. A 37% reduction in execution time was measured in a memset+mremap+munmap microbenchmark. "Remove zero_user()" (Matthew Wilcox) expunges zero_user() in favor of the more modern memzero_page(). "mm/huge_memory: vmf_insert_folio_*() and vmf_insert_pfn_pud() fixes" (David Hildenbrand) addresses some warts which David noticed in the huge page code. These were not known to be causing any issues at this time. "mm/damon: use alloc_migrate_target() for DAMOS_MIGRATE_{HOT,COLD" (SeongJae Park) provides some cleanup and consolidation work in DAMON. "use vm_flags_t consistently" (Lorenzo Stoakes) uses vm_flags_t in places where we were inappropriately using other types. "mm/memfd: Reserve hugetlb folios before allocation" (Vivek Kasireddy) increases the reliability of large page allocation in the memfd code. "mm: Remove pXX_devmap page table bit and pfn_t type" (Alistair Popple) removes several now-unneeded PFN_* flags. "mm/damon: decouple sysfs from core" (SeongJae Park) implememnts some cleanup and maintainability work in the DAMON sysfs layer. "madvise cleanup" (Lorenzo Stoakes) does quite a lot of cleanup/maintenance work in the madvise() code. "madvise anon_name cleanups" (Vlastimil Babka) provides additional cleanups on top or Lorenzo's effort. "Implement numa node notifier" (Oscar Salvador) creates a standalone notifier for NUMA node memory state changes. Previously these were lumped under the more general memory on/offline notifier. "Make MIGRATE_ISOLATE a standalone bit" (Zi Yan) cleans up the pageblock isolation code and fixes a potential issue which doesn't seem to cause any problems in practice. "selftests/damon: add python and drgn based DAMON sysfs functionality tests" (SeongJae Park) adds additional drgn- and python-based DAMON selftests which are more comprehensive than the existing selftest suite. "Misc rework on hugetlb faulting path" (Oscar Salvador) fixes a rather obscure deadlock in the hugetlb fault code and follows that fix with a series of cleanups. "cma: factor out allocation logic from __cma_declare_contiguous_nid" (Mike Rapoport) rationalizes and cleans up the highmem-specific code in the CMA allocator. "mm/migration: rework movable_ops page migration (part 1)" (David Hildenbrand) provides cleanups and future-preparedness to the migration code. "mm/damon: add trace events for auto-tuned monitoring intervals and DAMOS quota" (SeongJae Park) adds some tracepoints to some DAMON auto-tuning code. "mm/damon: fix misc bugs in DAMON modules" (SeongJae Park) does that. "mm/damon: misc cleanups" (SeongJae Park) also does what it claims. "mm: folio_pte_batch() improvements" (David Hildenbrand) cleans up the large folio PTE batching code. "mm/damon/vaddr: Allow interleaving in migrate_{hot,cold} actions" (SeongJae Park) facilitates dynamic alteration of DAMON's inter-node allocation policy. "Remove unmap_and_put_page()" (Vishal Moola) provides a couple of page->folio conversions. "mm: per-node proactive reclaim" (Davidlohr Bueso) implements a per-node control of proactive reclaim - beyond the current memcg-based implementation. "mm/damon: remove damon_callback" (SeongJae Park) replaces the damon_callback interface with a more general and powerful damon_call()+damos_walk() interface. "mm/mremap: permit mremap() move of multiple VMAs" (Lorenzo Stoakes) implements a number of mremap cleanups (of course) in preparation for adding new mremap() functionality: newly permit the remapping of multiple VMAs when the user is specifying MREMAP_FIXED. It still excludes some specialized situations where this cannot be performed reliably. "drop hugetlb_free_pgd_range()" (Anthony Yznaga) switches some sparc hugetlb code over to the generic version and removes the thus-unneeded hugetlb_free_pgd_range(). "mm/damon/sysfs: support periodic and automated stats update" (SeongJae Park) augments the present userspace-requested update of DAMON sysfs monitoring files. Automatic update is now provided, along with a tunable to control the update interval. "Some randome fixes and cleanups to swapfile" (Kemeng Shi) does what is claims. "mm: introduce snapshot_page" (Luiz Capitulino and David Hildenbrand) provides (and uses) a means by which debug-style functions can grab a copy of a pageframe and inspect it locklessly without tripping over the races inherent in operating on the live pageframe directly. "use per-vma locks for /proc/pid/maps reads" (Suren Baghdasaryan) addresses the large contention issues which can be triggered by reads from that procfs file. Latencies are reduced by more than half in some situations. The series also introduces several new selftests for the /proc/pid/maps interface. "__folio_split() clean up" (Zi Yan) cleans up __folio_split()! "Optimize mprotect() for large folios" (Dev Jain) provides some quite large (>3x) speedups to mprotect() when dealing with large folios. "selftests/mm: reuse FORCE_READ to replace "asm volatile("" : "+r" (XXX));" and some cleanup" (wang lian) does some cleanup work in the selftests code. "tools/testing: expand mremap testing" (Lorenzo Stoakes) extends the mremap() selftest in several ways, including adding more checking of Lorenzo's recently added "permit mremap() move of multiple VMAs" feature. "selftests/damon/sysfs.py: test all parameters" (SeongJae Park) extends the DAMON sysfs interface selftest so that it tests all possible user-requested parameters. Rather than the present minimal subset" * tag 'mm-stable-2025-07-30-15-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (370 commits) MAINTAINERS: add missing headers to mempory policy & migration section MAINTAINERS: add missing file to cgroup section MAINTAINERS: add MM MISC section, add missing files to MISC and CORE MAINTAINERS: add missing zsmalloc file MAINTAINERS: add missing files to page alloc section MAINTAINERS: add missing shrinker files MAINTAINERS: move memremap.[ch] to hotplug section MAINTAINERS: add missing mm_slot.h file THP section MAINTAINERS: add missing interval_tree.c to memory mapping section MAINTAINERS: add missing percpu-internal.h file to per-cpu section mm/page_alloc: remove trace_mm_alloc_contig_migrate_range_info() selftests/damon: introduce _common.sh to host shared function selftests/damon/sysfs.py: test runtime reduction of DAMON parameters selftests/damon/sysfs.py: test non-default parameters runtime commit selftests/damon/sysfs.py: generalize DAMON context commit assertion selftests/damon/sysfs.py: generalize monitoring attributes commit assertion selftests/damon/sysfs.py: generalize DAMOS schemes commit assertion selftests/damon/sysfs.py: test DAMOS filters commitment selftests/damon/sysfs.py: generalize DAMOS scheme commit assertion selftests/damon/sysfs.py: test DAMOS destinations commitment ...

mm/vma: refactor vma_modify_flags_name() to vma_modify_name()

2025-07-25T02:12:28+00:00

The single instance in which we use this function doesn't actually need to change VMA flags, so remove this parameter and update the caller accordingly. [lorenzo.stoakes@oracle.com: correct comment] Link: https://lkml.kernel.org/r/77f45b2e-a748-4635-9381-a5051091087f@lucifer.local Link: https://lkml.kernel.org/r/20250714135839.178032-1-lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Vlastimil Babka Acked-by: David Hildenbrand Reviewed-by: Liam R. Howlett Cc: Jann Horn Signed-off-by: Andrew Morton

mm: update core kernel code to use vm_flags_t consistently

2025-07-10T05:42:13+00:00

The core kernel code is currently very inconsistent in its use of vm_flags_t vs. unsigned long. This prevents us from changing the type of vm_flags_t in the future and is simply not correct, so correct this. While this results in rather a lot of churn, it is a critical pre-requisite for a future planned change to VMA flag type. Additionally, update VMA userland tests to account for the changes. To make review easier and to break things into smaller parts, driver and architecture-specific changes is left for a subsequent commit. The code has been adjusted to cascade the changes across all calling code as far as is needed. We will adjust architecture-specific and driver code in a subsequent patch. Overall, this patch does not introduce any functional change. Link: https://lkml.kernel.org/r/d1588e7bb96d1ea3fe7b9df2c699d5b4592d901d.1750274467.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Acked-by: Kees Cook Acked-by: Mike Rapoport (Microsoft) Acked-by: Jan Kara Acked-by: Christian Brauner Reviewed-by: Vlastimil Babka Acked-by: Oscar Salvador Reviewed-by: Pedro Falcato Acked-by: Zi Yan Acked-by: David Hildenbrand Reviewed-by: Anshuman Khandual Cc: Jann Horn Cc: Liam R. Howlett Cc: Catalin Marinas Cc: Jarkko Sakkinen Signed-off-by: Andrew Morton

mm/vma: use vmg->target to specify target VMA for new VMA merge

2025-07-10T05:42:11+00:00

In commit 3a75ccba047b ("mm: simplify vma merge structure and expand comments") we introduced the vmg->target field to make the merging of existing VMAs simpler - clarifying precisely which VMA would eventually become the merged VMA once the merge operation was complete. New VMA merging did not get quite the same treatment, retaining the rather confusing convention of storing the target VMA in vmg->middle. This patch corrects this state of affairs, utilising vmg->target for this purpose for both vma_merge_new_range() and also for vma_expand(). We retain the WARN_ON for vmg->middle being specified in vma_merge_new_range() as doing so would make no sense, but add an additional debug assert for setting vmg->target. This patch additionally updates VMA userland testing to account for this change. [lorenzo.stoakes@oracle.com: make comment consistent in vma_expand()] Link: https://lkml.kernel.org/r/c54f45e3-a6ac-4749-93c0-cc9e3080ee37@lucifer.local Link: https://lkml.kernel.org/r/20250613184807.108089-1-lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Vlastimil Babka Cc: Jann Horn Cc: Kees Cook Cc: Liam Howlett Signed-off-by: Andrew Morton