linux/tools/testing/vma, branch v6.14

tools: add VM_WARN_ON_VMG definition

2025-01-26T04:22:46Z

vma tests compilation yields the following error: vma.c:732:9: error: implicit declaration of function ‘VM_WARN_ON_VMG’ Fix it by adding missing VM_WARN_ON_VMG() definition. Link: https://lkml.kernel.org/r/20250116181538.759469-1-surenb@google.com Fixes: e3a7ae85f87c ("mm/debug: prefer VM_WARN_ON_VMG() to report VMG debug warnings") Signed-off-by: Suren Baghdasaryan Reviewed-by: Lorenzo Stoakes Cc: Liam R. Howlett Signed-off-by: Andrew Morton

mm: make mmap_region() internal

2025-01-26T04:22:38Z

Now that we have removed the one user of mmap_region() outside of mm, make it internal and add it to vma.c so it can be userland tested. This ensures that all external memory mappings are performed using the appropriate interfaces and allows us to modify memory mapping logic as we see fit. Additionally expand test stubs to allow for the mmap_region() code to compile and be userland testable. Link: https://lkml.kernel.org/r/de5a3c574d35c26237edf20a1d8652d7305709c9.1735819274.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Reviewed-by: Liam R. Howlett Cc: Jann Horn Cc: Thomas Bogendoerfer Cc: Vlastimil Babka Signed-off-by: Andrew Morton

tools: testing: add simple __mmap_region() userland test

2025-01-26T04:22:18Z

Introduce demonstrative, basic, __mmap_region() test upon which we can base further work upon moving forwards. This simply asserts that mappings can be made and merges occur as expected. As part of this change, fix the security_vm_enough_memory_mm() stub which was previously incorrectly implemented. Link: https://lkml.kernel.org/r/20241213162409.41498-1-lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Cc: Jann Horn Cc: Liam R. Howlett Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: convert mm_lock_seq to a proper seqcount

2025-01-14T06:40:50Z

Convert mm_lock_seq to be seqcount_t and change all mmap_write_lock variants to increment it, in-line with the usual seqcount usage pattern. This lets us check whether the mmap_lock is write-locked by checking mm_lock_seq.sequence counter (odd=locked, even=unlocked). This will be used when implementing mmap_lock speculation functions. As a result vm_lock_seq is also change to be unsigned to match the type of mm_lock_seq.sequence. Link: https://lkml.kernel.org/r/20241122174416.1367052-2-surenb@google.com Suggested-by: Peter Zijlstra Signed-off-by: Suren Baghdasaryan Reviewed-by: Liam R. Howlett Cc: Christian Brauner Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: Hillf Danton Cc: Hugh Dickins Cc: Jann Horn Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Lorenzo Stoakes Cc: Mateusz Guzik Cc: Matthew Wilcox Cc: Mel Gorman Cc: Michal Hocko Cc: Minchan Kim Cc: Oleg Nesterov Cc: Pasha Tatashin Cc: Paul E. McKenney Cc: Peter Xu Cc: Shakeel Butt Cc: Sourav Panda Cc: Vlastimil Babka Cc: Wei Yang Signed-off-by: Andrew Morton

mm/vma: move __vm_munmap() to mm/vma.c

2025-01-14T06:40:43Z

This was arbitrarily left in mmap.c it makes no sense being there, move it to vma.c to render it testable. Link: https://lkml.kernel.org/r/5e5e81807c54dfbe363edb2d431eb3d7a37fcdba.1733248985.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Cc: Al Viro Cc: Christian Brauner Cc: Eric W. Biederman Cc: Jan Kara Cc: Jann Horn Cc: Kees Cook Cc: Liam R. Howlett Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm/vma: move stack expansion logic to mm/vma.c

2025-01-14T06:40:43Z

We build on previous work making expand_downwards() an entirely internal function. This logic is subtle and so it is highly useful to get it into vma.c so we can then userland unit test. We must additionally move acct_stack_growth() to vma.c as it is a helper function used by both expand_downwards() and expand_upwards(). We are also then able to mark anon_vma_interval_tree_pre_update_vma() and anon_vma_interval_tree_post_update_vma() static as these are no longer used by anything else. Link: https://lkml.kernel.org/r/0feb104eff85922019d4fb29280f3afb130c5204.1733248985.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Cc: Al Viro Cc: Christian Brauner Cc: Eric W. Biederman Cc: Jan Kara Cc: Jann Horn Cc: Kees Cook Cc: Liam R. Howlett Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm/vma: move unmapped_area() internals to mm/vma.c

2025-01-14T06:40:43Z

We want to be able to unit test the unmapped area logic, so move it to mm/vma.c. The wrappers which invoke this remain in place in mm/mmap.c. In addition, naturally, update the existing test code to enable this to be compiled in userland. Link: https://lkml.kernel.org/r/53a57a52a64ea54e9d129d2e2abca3a538022379.1733248985.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Cc: Al Viro Cc: Christian Brauner Cc: Eric W. Biederman Cc: Jan Kara Cc: Jann Horn Cc: Kees Cook Cc: Liam R. Howlett Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm/vma: move brk() internals to mm/vma.c

2025-01-14T06:40:42Z

Patch series "mm/vma: make more mmap logic userland testable". This series carries on the work started in previous series and continued in commit 52956b0d7fb9 ("mm: isolate mmap internal logic to mm/vma.c"), moving the remainder of memory mapping implementation details logic into mm/vma.c allowing the bulk of the mapping logic to be unit tested. It is highly useful to do so, as this means we can both fundamentally test this core logic, and introduce regression tests to ensure any issues previously resolved do not recur. Vitally, this includes the do_brk_flags() function, meaning we have both core means of userland mapping memory now testable. Performance testing was performed after this change given the brk() system call's sensitivity to change, and no performance regression was observed. The stack expansion logic is also moved into mm/vma.c, which necessitates a change in the API exposed to the exec code, removing the invocation of the expand_downwards() function used in get_arg_page() and instead adding mmap_read_lock_maybe_expand() to wrap this. This patch (of 5): Now we have moved mmap_region() internals to mm/vma.c, making it available to userland testing, it makes sense to do the same with brk(). This continues the pattern of VMA heavy lifting being done in mm/vma.c in an environment where it can be subject to straightforward unit and regression testing, with other VMA-adjacent files becoming wrappers around this functionality. [lorenzo.stoakes@oracle.com: add missing personality header import] Link: https://lkml.kernel.org/r/2a717265-985f-45eb-9257-8b2857088ed4@lucifer.local Link: https://lkml.kernel.org/r/cover.1733248985.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/3d24b9e67bb0261539ca921d1188a10a1b4d4357.1733248985.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Cc: Al Viro Cc: Christian Brauner Cc: Eric W. Biederman Cc: Jan Kara Cc: Jann Horn Cc: Kees Cook Cc: Liam R. Howlett Cc: Vlastimil Babka Signed-off-by: Andrew Morton

tools: fix atomic_set() definition to set the value correctly

2025-01-13T03:03:35Z

Currently vma test is failing because of the new vma_assert_attached() assertion. The check is failing because previous refcount_set() inside vma_mark_attached() is a NoOp. Fix the definition of atomic_set() to correctly set the value of the atomic. Link: https://lkml.kernel.org/r/20241227222220.1726384-1-surenb@google.com Fixes: 9325b8b5a1cb ("tools: add skeleton code for userland testing of VMA logic") Signed-off-by: Suren Baghdasaryan Reviewed-by: Lorenzo Stoakes Cc: Jann Horn Cc: Liam R. Howlett Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton

tools: testing: add additional vma_internal.h stubs

2024-11-07T04:11:19Z

Patch series "fix error handling in mmap_region() and refactor", v3. The mmap_region() function is somewhat terrifying, with spaghetti-like control flow and numerous means by which issues can arise and incomplete state, memory leaks and other unpleasantness can occur. This series goes to great lengths to simplify how mmap_region() works and to avoid unwinding errors late on in the process of setting up the VMA for the new mapping, and equally avoids such operations occurring while the VMA is in an inconsistent state. This series builds on the previously submitted hotfix patches (see link to v2 below) which addresses the most critical issues around mmap_region(), and further works to improve mmap_region() complexity, stability, and testability. This series moves the code to mm/vma.c to render it userland testable, refactors and simplifies it into smaller functions that are significantly more readable. It additionally avoids performing an attempt at a second merge mid-way through allocating a new VMA, a dubious proposition at best and one that is highly subject to subtle bugs. Rather than do this, we simply note that we ought to retry the merge and do this as a final step. This patch (of 3): Add some additional vma_internal.h stubs in preparation for __mmap_region() being moved to mm/vma.c. Without these the move would result in the tests no longer compiling. Link: https://lkml.kernel.org/r/cover.1729858176.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/74b27e159e261d2ac1fe66a130edad1d61fdc176.1729858176.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Cc: Jann Horn Cc: Liam R. Howlett Cc: Linus Torvalds Cc: Peter Xu Cc: Vlastimil Babka Signed-off-by: Andrew Morton