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2025-01-13mm/vma: move brk() internals to mm/vma.cLorenzo Stoakes1-0/+1
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 <lorenzo.stoakes@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <kees@kernel.org> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-06mm: isolate mmap internal logic to mm/vma.cLorenzo Stoakes1-0/+5
In previous commits we effected improvements to the mmap() logic in mmap_region() and its newly introduced internal implementation function __mmap_region(). However as these changes are intended to be backported, we kept the delta as small as is possible and made as few changes as possible to the newly introduced mm/vma.* files. Take the opportunity to move this logic to mm/vma.c which not only isolates it, but also makes it available for later userland testing which can help us catch such logic errors far earlier. Link: https://lkml.kernel.org/r/93fc2c3aa37dd30590b7e4ee067dfd832007bf7e.1729858176.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01mm: remove duplicated include in vma_internal.hYang Li1-1/+0
The header files linux/bug.h is included twice in vma_internal.h, so one inclusion of each can be removed. Link: https://lkml.kernel.org/r/20240802060216.24591-1-yang.lee@linux.alibaba.com Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Reported-by: Abaci Robot <abaci@linux.alibaba.com> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9636 Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01mm: move internal core VMA manipulation functions to own fileLorenzo Stoakes1-0/+50
This patch introduces vma.c and moves internal core VMA manipulation functions to this file from mmap.c. This allows us to isolate VMA functionality in a single place such that we can create userspace testing code that invokes this functionality in an environment where we can implement simple unit tests of core functionality. This patch ensures that core VMA functionality is explicitly marked as such by its presence in mm/vma.h. It also places the header includes required by vma.c in vma_internal.h, which is simply imported by vma.c. This makes the VMA functionality testable, as userland testing code can simply stub out functionality as required. Link: https://lkml.kernel.org/r/c77a6aafb4c42aaadb8e7271a853658cbdca2e22.1722251717.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Brendan Higgins <brendanhiggins@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Gow <davidgow@google.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jan Kara <jack@suse.cz> Cc: Kees Cook <kees@kernel.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Rae Moar <rmoar@google.com> Cc: SeongJae Park <sj@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Pengfei Xu <pengfei.xu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>