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2020-08-07mm/mremap: start addresses are properly alignedWei Yang
After previous cleanup, extent is the minimal step for both source and destination. This means when extent is HPAGE_PMD_SIZE or PMD_SIZE, old_addr and new_addr are properly aligned too. Since these two functions are only invoked in move_page_tables, it is safe to remove the check now. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Dmitry Osipenko <digetx@gmail.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Thomas Hellstrom (VMware) <thomas_os@shipmail.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <yang.shi@linux.alibaba.com> Link: http://lkml.kernel.org/r/20200708095028.41706-4-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07mm/mremap: calculate extent in one placeWei Yang
Page tables is moved on the base of PMD. This requires both source and destination range should meet the requirement. Current code works well since move_huge_pmd() and move_normal_pmd() would check old_addr and new_addr again. And then return to move_ptes() if the either of them is not aligned. Instead of calculating the extent separately, it is better to calculate in one place, so we know it is not necessary to try move pmd. By doing so, the logic seems a little clear. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Dmitry Osipenko <digetx@gmail.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Thomas Hellstrom (VMware) <thomas_os@shipmail.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <yang.shi@linux.alibaba.com> Link: http://lkml.kernel.org/r/20200708095028.41706-3-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07mm/mremap: it is sure to have enough space when extent meets requirementWei Yang
Patch series "mm/mremap: cleanup move_page_tables() a little", v5. move_page_tables() tries to move page table by PMD or PTE. The root reason is if it tries to move PMD, both old and new range should be PMD aligned. But current code calculate old range and new range separately. This leads to some redundant check and calculation. This cleanup tries to consolidate the range check in one place to reduce some extra range handling. This patch (of 3): old_end is passed to these two functions to check whether there is enough space to do the move, while this check is done before invoking these functions. These two functions only would be invoked when extent meets the requirement and there is one check before invoking these functions: if (extent > old_end - old_addr) extent = old_end - old_addr; This implies (old_end - old_addr) won't fail the check in these two functions. Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Dmitry Osipenko <digetx@gmail.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Thomas Hellstrom (VMware) <thomas_os@shipmail.org> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Peter Xu <peterx@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Thomas Hellstrom <thellstrom@vmware.com> Link: http://lkml.kernel.org/r/20200710092835.56368-1-richard.weiyang@linux.alibaba.com Link: http://lkml.kernel.org/r/20200710092835.56368-2-richard.weiyang@linux.alibaba.com Link: http://lkml.kernel.org/r/20200708095028.41706-1-richard.weiyang@linux.alibaba.com Link: http://lkml.kernel.org/r/20200708095028.41706-2-richard.weiyang@linux.alibaba.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-13mm: document warning in move_normal_pmd() and make it warn only onceLinus Torvalds
Naresh Kamboju reported that the LTP tests can cause warnings on i386 going back all the way to v5.0, and bisected it to commit 2c91bd4a4e2e ("mm: speed up mremap by 20x on large regions"). The warning in move_normal_pmd() is actually mostly correct, but we have a very unusual special case at process creation time, when we may move the stack down with an overlapping mode (kind of like a "memmove()" except using the page tables). And when you have just the right condition of "move a large initial stack by the right alignment in the end, but with the early part of the move being only page-aligned", we'll be in a situation where we're trying to move a normal PMD entry on top of an already existing - but now empty - PMD entry. The warning is still worth having, in case it ever triggers other cases, and perhaps as a reminder that we could do the stack move case more efficiently (although it's clearly rare enough that it probably doesn't matter). But make it do WARN_ON_ONCE(), so that you can't flood the logs with it. And add a *big* comment above it to explain and remind us what's going on, because it took some figuring out to see how this could trigger. Kudos to Joel Fernandes for debugging this. Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Debugged-and-acked-by: Joel Fernandes <joel@joelfernandes.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09mmap locking API: convert mmap_sem commentsMichel Lespinasse
Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09mmap locking API: use coccinelle to convert mmap_sem rwsem call sitesMichel Lespinasse
This change converts the existing mmap_sem rwsem calls to use the new mmap locking API instead. The change is generated using coccinelle with the following rule: // spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir . @@ expression mm; @@ ( -init_rwsem +mmap_init_lock | -down_write +mmap_write_lock | -down_write_killable +mmap_write_lock_killable | -down_write_trylock +mmap_write_trylock | -up_write +mmap_write_unlock | -downgrade_write +mmap_write_downgrade | -down_read +mmap_read_lock | -down_read_killable +mmap_read_lock_killable | -down_read_trylock +mmap_read_trylock | -up_read +mmap_read_unlock ) -(&mm->mmap_sem) +(mm) Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-04Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge yet more updates from Andrew Morton: - More MM work. 100ish more to go. Mike Rapoport's "mm: remove __ARCH_HAS_5LEVEL_HACK" series should fix the current ppc issue - Various other little subsystems * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (127 commits) lib/ubsan.c: fix gcc-10 warnings tools/testing/selftests/vm: remove duplicate headers selftests: vm: pkeys: fix multilib builds for x86 selftests: vm: pkeys: use the correct page size on powerpc selftests/vm/pkeys: override access right definitions on powerpc selftests/vm/pkeys: test correct behaviour of pkey-0 selftests/vm/pkeys: introduce a sub-page allocator selftests/vm/pkeys: detect write violation on a mapped access-denied-key page selftests/vm/pkeys: associate key on a mapped page and detect write violation selftests/vm/pkeys: associate key on a mapped page and detect access violation selftests/vm/pkeys: improve checks to determine pkey support selftests/vm/pkeys: fix assertion in test_pkey_alloc_exhaust() selftests/vm/pkeys: fix number of reserved powerpc pkeys selftests/vm/pkeys: introduce powerpc support selftests/vm/pkeys: introduce generic pkey abstractions selftests: vm: pkeys: use the correct huge page size selftests/vm/pkeys: fix alloc_random_pkey() to make it really random selftests/vm/pkeys: fix assertion in pkey_disable_set/clear() selftests/vm/pkeys: fix pkey_disable_clear() selftests: vm: pkeys: add helpers for pkey bits ...
2020-06-04mm: use false for bool variableZou Wei
Fixes coccicheck warnings: mm/zbud.c:246:1-20: WARNING: Assignment of 0/1 to bool variable mm/mremap.c:777:2-8: WARNING: Assignment of 0/1 to bool variable mm/huge_memory.c:525:9-10: WARNING: return of 0/1 in function 'is_transparent_hugepage' with return type bool Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Zou Wei <zou_wei@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1586835930-47076-1-git-send-email-zou_wei@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-04mm: Fix mremap not considering huge pmd devmapFan Yang
The original code in mm/mremap.c checks huge pmd by: if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd)) { However, a DAX mapped nvdimm is mapped as huge page (by default) but it is not transparent huge page (_PAGE_PSE | PAGE_DEVMAP). This commit changes the condition to include the case. This addresses CVE-2020-10757. Fixes: 5c7fb56e5e3f ("mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd") Cc: <stable@vger.kernel.org> Reported-by: Fan Yang <Fan_Yang@sjtu.edu.cn> Signed-off-by: Fan Yang <Fan_Yang@sjtu.edu.cn> Tested-by: Fan Yang <Fan_Yang@sjtu.edu.cn> Tested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-14userfaultfd: fix remap event with MREMAP_DONTUNMAPBrian Geffon
A user is not required to set a new address when using MREMAP_DONTUNMAP as it can be used without MREMAP_FIXED. When doing so the remap event will use new_addr which may not have been set and we didn't propagate it back other then in the return value of remap_to. Because ret is always the new address it's probably more correct to use it rather than new_addr on the remap_event_complete call, and it resolves this bug. Fixes: e346b3813067d4b ("mm/mremap: add MREMAP_DONTUNMAP to mremap()") Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Brian Geffon <bgeffon@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: "Michael S . Tsirkin" <mst@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Sonny Rao <sonnyrao@google.com> Cc: Joel Fernandes <joel@joelfernandes.org> Link: http://lkml.kernel.org/r/20200506172158.218366-1-bgeffon@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-19mm: Fix MREMAP_DONTUNMAP accounting on VMA mergeBrian Geffon
When remapping a mapping where a portion of a VMA is remapped into another portion of the VMA it can cause the VMA to become split. During the copy_vma operation the VMA can actually be remerged if it's an anonymous VMA whose pages have not yet been faulted. This isn't normally a problem because at the end of the remap the original portion is unmapped causing it to become split again. However, MREMAP_DONTUNMAP leaves that original portion in place which means that the VMA which was split and then remerged is not actually split at the end of the mremap. This patch fixes a bug where we don't detect that the VMAs got remerged and we end up putting back VM_ACCOUNT on the next mapping which is completely unreleated. When that next mapping is unmapped it results in incorrectly unaccounting for the memory which was never accounted, and eventually we will underflow on the memory comittment. There is also another issue which is similar, we're currently accouting for the number of pages in the new_vma but that's wrong. We need to account for the length of the remap operation as that's all that is being added. If there was a mapping already at that location its comittment would have been adjusted as part of the munmap at the start of the mremap. A really simple repro can be seen in: https://gist.github.com/bgaff/e101ce99da7d9a8c60acc641d07f312c Fixes: e346b3813067 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Brian Geffon <bgeffon@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02mm/mremap: add MREMAP_DONTUNMAP to mremap()Brian Geffon
When remapping an anonymous, private mapping, if MREMAP_DONTUNMAP is set, the source mapping will not be removed. The remap operation will be performed as it would have been normally by moving over the page tables to the new mapping. The old vma will have any locked flags cleared, have no pagetables, and any userfaultfds that were watching that range will continue watching it. For a mapping that is shared or not anonymous, MREMAP_DONTUNMAP will cause the mremap() call to fail. Because MREMAP_DONTUNMAP always results in moving a VMA you MUST use the MREMAP_MAYMOVE flag, it's not possible to resize a VMA while also moving with MREMAP_DONTUNMAP so old_len must always be equal to the new_len otherwise it will return -EINVAL. We hope to use this in Chrome OS where with userfaultfd we could write an anonymous mapping to disk without having to STOP the process or worry about VMA permission changes. This feature also has a use case in Android, Lokesh Gidra has said that "As part of using userfaultfd for GC, We'll have to move the physical pages of the java heap to a separate location. For this purpose mremap will be used. Without the MREMAP_DONTUNMAP flag, when I mremap the java heap, its virtual mapping will be removed as well. Therefore, we'll require performing mmap immediately after. This is not only time consuming but also opens a time window where a native thread may call mmap and reserve the java heap's address range for its own usage. This flag solves the problem." [bgeffon@google.com: v6] Link: http://lkml.kernel.org/r/20200218173221.237674-1-bgeffon@google.com [bgeffon@google.com: v7] Link: http://lkml.kernel.org/r/20200221174248.244748-1-bgeffon@google.com Signed-off-by: Brian Geffon <bgeffon@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Lokesh Gidra <lokeshgidra@google.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Michael S . Tsirkin" <mst@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will Deacon <will@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Sonny Rao <sonnyrao@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Yu Zhao <yuzhao@google.com> Cc: Jesse Barnes <jsbarnes@google.com> Cc: Nathan Chancellor <natechancellor@gmail.com> Cc: Florian Weimer <fweimer@redhat.com> Link: http://lkml.kernel.org/r/20200207201856.46070-1-bgeffon@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-02mm/vma: make is_vma_temporary_stack() available for general useAnshuman Khandual
Currently the declaration and definition for is_vma_temporary_stack() are scattered. Lets make is_vma_temporary_stack() helper available for general use and also drop the declaration from (include/linux/huge_mm.h) which is no longer required. While at this, rename this as vma_is_temporary_stack() in line with existing helpers. This should not cause any functional change. Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Ingo Molnar <mingo@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1582782965-3274-4-git-send-email-anshuman.khandual@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-03-26mm/mremap: Add comment explaining the untagging behaviour of mremap()Will Deacon
Commit dcde237319e6 ("mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()") changed mremap() so that only the 'old' address is untagged, leaving the 'new' address in the form it was passed from userspace. This prevents the unexpected creation of aliasing virtual mappings in userspace, but looks a bit odd when you read the code. Add a comment justifying the untagging behaviour in mremap(). Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-02-20mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()Catalin Marinas
Currently the arm64 kernel ignores the top address byte passed to brk(), mmap() and mremap(). When the user is not aware of the 56-bit address limit or relies on the kernel to return an error, untagging such pointers has the potential to create address aliases in user-space. Passing a tagged address to munmap(), madvise() is permitted since the tagged pointer is expected to be inside an existing mapping. The current behaviour breaks the existing glibc malloc() implementation which relies on brk() with an address beyond 56-bit to be rejected by the kernel. Remove untagging in the above functions by partially reverting commit ce18d171cb73 ("mm: untag user pointers in mmap/munmap/mremap/brk"). In addition, update the arm64 tagged-address-abi.rst document accordingly. Link: https://bugzilla.redhat.com/1797052 Fixes: ce18d171cb73 ("mm: untag user pointers in mmap/munmap/mremap/brk") Cc: <stable@vger.kernel.org> # 5.4.x- Cc: Florian Weimer <fweimer@redhat.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reported-by: Victor Stinner <vstinner@redhat.com> Acked-by: Will Deacon <will@kernel.org> Acked-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
2019-12-01mm/mmap.c: use IS_ERR_VALUE to check return value of get_unmapped_areaGaowei Pu
get_unmapped_area() returns an address or -errno on failure. Historically we have checked for the failure by offset_in_page() which is correct but quite hard to read. Newer code started using IS_ERR_VALUE which is much easier to read. Convert remaining users of offset_in_page as well. [mhocko@suse.com: rewrite changelog] [mhocko@kernel.org: fix mremap.c and uprobes.c sites also] Link: http://lkml.kernel.org/r/20191012102512.28051-1-pugaowei@gmail.com Signed-off-by: Gaowei Pu <pugaowei@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Rik van Riel <riel@surriel.com> Cc: Qian Cai <cai@lca.pw> Cc: Shakeel Butt <shakeelb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-25mm: untag user pointers in mmap/munmap/mremap/brkCatalin Marinas
There isn't a good reason to differentiate between the user address space layout modification syscalls and the other memory permission/attributes ones (e.g. mprotect, madvise) w.r.t. the tagged address ABI. Untag the user addresses on entry to these functions. Link: http://lkml.kernel.org/r/20190821164730.47450-2-catalin.marinas@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Will Deacon <will@kernel.org> Acked-by: Andrey Konovalov <andreyknvl@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Szabolcs Nagy <szabolcs.nagy@arm.com> Cc: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Dave P Martin <Dave.Martin@arm.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-09-25mm: untag user pointers passed to memory syscallsAndrey Konovalov
This patch is a part of a series that extends kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. This patch allows tagged pointers to be passed to the following memory syscalls: get_mempolicy, madvise, mbind, mincore, mlock, mlock2, mprotect, mremap, msync, munlock, move_pages. The mmap and mremap syscalls do not currently accept tagged addresses. Architectures may interpret the tag as a background colour for the corresponding vma. Link: http://lkml.kernel.org/r/aaf0c0969d46b2feb9017f3e1b3ef3970b633d91.1563904656.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Eric Auger <eric.auger@redhat.com> Cc: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Jens Wiklander <jens.wiklander@linaro.org> Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14mm/mmu_notifier: contextual information for event triggering invalidationJérôme Glisse
CPU page table update can happens for many reasons, not only as a result of a syscall (munmap(), mprotect(), mremap(), madvise(), ...) but also as a result of kernel activities (memory compression, reclaim, migration, ...). Users of mmu notifier API track changes to the CPU page table and take specific action for them. While current API only provide range of virtual address affected by the change, not why the changes is happening. This patchset do the initial mechanical convertion of all the places that calls mmu_notifier_range_init to also provide the default MMU_NOTIFY_UNMAP event as well as the vma if it is know (most invalidation happens against a given vma). Passing down the vma allows the users of mmu notifier to inspect the new vma page protection. The MMU_NOTIFY_UNMAP is always the safe default as users of mmu notifier should assume that every for the range is going away when that event happens. A latter patch do convert mm call path to use a more appropriate events for each call. This is done as 2 patches so that no call site is forgotten especialy as it uses this following coccinelle patch: %<---------------------------------------------------------------------- @@ identifier I1, I2, I3, I4; @@ static inline void mmu_notifier_range_init(struct mmu_notifier_range *I1, +enum mmu_notifier_event event, +unsigned flags, +struct vm_area_struct *vma, struct mm_struct *I2, unsigned long I3, unsigned long I4) { ... } @@ @@ -#define mmu_notifier_range_init(range, mm, start, end) +#define mmu_notifier_range_init(range, event, flags, vma, mm, start, end) @@ expression E1, E3, E4; identifier I1; @@ <... mmu_notifier_range_init(E1, +MMU_NOTIFY_UNMAP, 0, I1, I1->vm_mm, E3, E4) ...> @@ expression E1, E2, E3, E4; identifier FN, VMA; @@ FN(..., struct vm_area_struct *VMA, ...) { <... mmu_notifier_range_init(E1, +MMU_NOTIFY_UNMAP, 0, VMA, E2, E3, E4) ...> } @@ expression E1, E2, E3, E4; identifier FN, VMA; @@ FN(...) { struct vm_area_struct *VMA; <... mmu_notifier_range_init(E1, +MMU_NOTIFY_UNMAP, 0, VMA, E2, E3, E4) ...> } @@ expression E1, E2, E3, E4; identifier FN; @@ FN(...) { <... mmu_notifier_range_init(E1, +MMU_NOTIFY_UNMAP, 0, NULL, E2, E3, E4) ...> } ---------------------------------------------------------------------->% Applied with: spatch --all-includes --sp-file mmu-notifier.spatch fs/proc/task_mmu.c --in-place spatch --sp-file mmu-notifier.spatch --dir kernel/events/ --in-place spatch --sp-file mmu-notifier.spatch --dir mm --in-place Link: http://lkml.kernel.org/r/20190326164747.24405-6-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Cc: Christian König <christian.koenig@amd.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krcmar <rkrcmar@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Christian Koenig <christian.koenig@amd.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm,mremap: bail out earlier in mremap_to under map pressureOscar Salvador
When using mremap() syscall in addition to MREMAP_FIXED flag, mremap() calls mremap_to() which does the following: 1) unmaps the destination region where we are going to move the map 2) If the new region is going to be smaller, we unmap the last part of the old region Then, we will eventually call move_vma() to do the actual move. move_vma() checks whether we are at least 4 maps below max_map_count before going further, otherwise it bails out with -ENOMEM. The problem is that we might have already unmapped the vma's in steps 1) and 2), so it is not possible for userspace to figure out the state of the vmas after it gets -ENOMEM, and it gets tricky for userspace to clean up properly on error path. While it is true that we can return -ENOMEM for more reasons (e.g: see may_expand_vm() or move_page_tables()), I think that we can avoid this scenario if we check early in mremap_to() if the operation has high chances to succeed map-wise. Should that not be the case, we can bail out before we even try to unmap anything, so we make sure the vma's are left untouched in case we are likely to be short of maps. The thumb-rule now is to rely on the worst-scenario case we can have. That is when both vma's (old region and new region) are going to be split in 3, so we get two more maps to the ones we already hold (one per each). If current map count + 2 maps still leads us to 4 maps below the threshold, we are going to pass the check in move_vma(). Of course, this is not free, as it might generate false positives when it is true that we are tight map-wise, but the unmap operation can release several vma's leading us to a good state. Another approach was also investigated [1], but it may be too much hassle for what it brings. [1] https://lore.kernel.org/lkml/20190219155320.tkfkwvqk53tfdojt@d104.suse.de/ Link: http://lkml.kernel.org/r/20190226091314.18446-1-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Cyril Hrubis <chrubis@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-04mm: speed up mremap by 20x on large regionsJoel Fernandes (Google)
Android needs to mremap large regions of memory during memory management related operations. The mremap system call can be really slow if THP is not enabled. The bottleneck is move_page_tables, which is copying each pte at a time, and can be really slow across a large map. Turning on THP may not be a viable option, and is not for us. This patch speeds up the performance for non-THP system by copying at the PMD level when possible. The speedup is an order of magnitude on x86 (~20x). On a 1GB mremap, the mremap completion times drops from 3.4-3.6 milliseconds to 144-160 microseconds. Before: Total mremap time for 1GB data: 3521942 nanoseconds. Total mremap time for 1GB data: 3449229 nanoseconds. Total mremap time for 1GB data: 3488230 nanoseconds. After: Total mremap time for 1GB data: 150279 nanoseconds. Total mremap time for 1GB data: 144665 nanoseconds. Total mremap time for 1GB data: 158708 nanoseconds. If THP is enabled the optimization is mostly skipped except in certain situations. [joel@joelfernandes.org: fix 'move_normal_pmd' unused function warning] Link: http://lkml.kernel.org/r/20181108224457.GB209347@google.com Link: http://lkml.kernel.org/r/20181108181201.88826-3-joelaf@google.com Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Cc: Julia Lawall <Julia.Lawall@lip6.fr> Cc: Michal Hocko <mhocko@kernel.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-04mm: treewide: remove unused address argument from pte_alloc functionsJoel Fernandes (Google)
Patch series "Add support for fast mremap". This series speeds up the mremap(2) syscall by copying page tables at the PMD level even for non-THP systems. There is concern that the extra 'address' argument that mremap passes to pte_alloc may do something subtle architecture related in the future that may make the scheme not work. Also we find that there is no point in passing the 'address' to pte_alloc since its unused. This patch therefore removes this argument tree-wide resulting in a nice negative diff as well. Also ensuring along the way that the enabled architectures do not do anything funky with the 'address' argument that goes unnoticed by the optimization. Build and boot tested on x86-64. Build tested on arm64. The config enablement patch for arm64 will be posted in the future after more testing. The changes were obtained by applying the following Coccinelle script. (thanks Julia for answering all Coccinelle questions!). Following fix ups were done manually: * Removal of address argument from pte_fragment_alloc * Removal of pte_alloc_one_fast definitions from m68k and microblaze. // Options: --include-headers --no-includes // Note: I split the 'identifier fn' line, so if you are manually // running it, please unsplit it so it runs for you. virtual patch @pte_alloc_func_def depends on patch exists@ identifier E2; identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; type T2; @@ fn(... - , T2 E2 ) { ... } @pte_alloc_func_proto_noarg depends on patch exists@ type T1, T2, T3, T4; identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; @@ ( - T3 fn(T1, T2); + T3 fn(T1); | - T3 fn(T1, T2, T4); + T3 fn(T1, T2); ) @pte_alloc_func_proto depends on patch exists@ identifier E1, E2, E4; type T1, T2, T3, T4; identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; @@ ( - T3 fn(T1 E1, T2 E2); + T3 fn(T1 E1); | - T3 fn(T1 E1, T2 E2, T4 E4); + T3 fn(T1 E1, T2 E2); ) @pte_alloc_func_call depends on patch exists@ expression E2; identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; @@ fn(... -, E2 ) @pte_alloc_macro depends on patch exists@ identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; identifier a, b, c; expression e; position p; @@ ( - #define fn(a, b, c) e + #define fn(a, b) e | - #define fn(a, b) e + #define fn(a) e ) Link: http://lkml.kernel.org/r/20181108181201.88826-2-joelaf@google.com Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Michal Hocko <mhocko@kernel.org> Cc: Julia Lawall <Julia.Lawall@lip6.fr> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: William Kucharski <william.kucharski@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28mm/mmu_notifier: use structure for invalidate_range_start/end calls v2Jérôme Glisse
To avoid having to change many call sites everytime we want to add a parameter use a structure to group all parameters for the mmu_notifier invalidate_range_start/end cakks. No functional changes with this patch. [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/20181205053628.3210-3-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krcmar <rkrcmar@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Felix Kuehling <felix.kuehling@amd.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> From: Jérôme Glisse <jglisse@redhat.com> Subject: mm/mmu_notifier: use structure for invalidate_range_start/end calls v3 fix build warning in migrate.c when CONFIG_MMU_NOTIFIER=n Link: http://lkml.kernel.org/r/20181213171330.8489-3-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26mm: mremap: downgrade mmap_sem to read when shrinkingYang Shi
Other than munmap, mremap might be used to shrink memory mapping too. So, it may hold write mmap_sem for long time when shrinking large mapping, as what commit ("mm: mmap: zap pages with read mmap_sem in munmap") described. The mremap() will not manipulate vmas anymore after __do_munmap() call for the mapping shrink use case, so it is safe to downgrade to read mmap_sem. So, the same optimization, which downgrades mmap_sem to read for zapping pages, is also feasible and reasonable to this case. The period of holding exclusive mmap_sem for shrinking large mapping would be reduced significantly with this optimization. MREMAP_FIXED and MREMAP_MAYMOVE are more complicated to adopt this optimization since they need manipulate vmas after do_munmap(), downgrading mmap_sem may create race window. Simple mapping shrink is the low hanging fruit, and it may cover the most cases of unmap with munmap together. [akpm@linux-foundation.org: tweak comment] [yang.shi@linux.alibaba.com: fix unsigned compare against 0 issue] Link: http://lkml.kernel.org/r/1538687672-17795-2-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1538067582-60038-1-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Cc: Colin Ian King <colin.king@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-18mremap: properly flush TLB before releasing the pageLinus Torvalds
Jann Horn points out that our TLB flushing was subtly wrong for the mremap() case. What makes mremap() special is that we don't follow the usual "add page to list of pages to be freed, then flush tlb, and then free pages". No, mremap() obviously just _moves_ the page from one page table location to another. That matters, because mremap() thus doesn't directly control the lifetime of the moved page with a freelist: instead, the lifetime of the page is controlled by the page table locking, that serializes access to the entry. As a result, we need to flush the TLB not just before releasing the lock for the source location (to avoid any concurrent accesses to the entry), but also before we release the destination page table lock (to avoid the TLB being flushed after somebody else has already done something to that page). This also makes the whole "need_flush" logic unnecessary, since we now always end up flushing the TLB for every valid entry. Reported-and-tested-by: Jann Horn <jannh@google.com> Acked-by: Will Deacon <will.deacon@arm.com> Tested-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-15mremap: remove LATENCY_LIMIT from mremap to reduce the number of TLB shootdownsMel Gorman
Commit 5d1904204c99 ("mremap: fix race between mremap() and page cleanning") fixed races between mremap and other operations for both file-backed and anonymous mappings. The file-backed was the most critical as it allowed the possibility that data could be changed on a physical page after page_mkclean returned which could trigger data loss or data integrity issues. A customer reported that the cost of the TLBs for anonymous regressions was excessive and resulting in a 30-50% drop in performance overall since this commit on a microbenchmark. Unfortunately I neither have access to the test-case nor can I describe what it does other than saying that mremap operations dominate heavily. This patch removes the LATENCY_LIMIT to handle TLB flushes on a PMD boundary instead of every 64 pages to reduce the number of TLB shootdowns by a factor of 8 in the ideal case. LATENCY_LIMIT was almost certainly used originally to limit the PTL hold times but the latency savings are likely offset by the cost of IPIs in many cases. This patch is not reported to completely restore performance but gets it within an acceptable percentage. The given metric here is simply described as "higher is better". Baseline that was known good 002: Metric: 91.05 004: Metric: 109.45 008: Metric: 73.08 016: Metric: 58.14 032: Metric: 61.09 064: Metric: 57.76 128: Metric: 55.43 Current 001: Metric: 54.98 002: Metric: 56.56 004: Metric: 41.22 008: Metric: 35.96 016: Metric: 36.45 032: Metric: 35.71 064: Metric: 35.73 128: Metric: 34.96 With patch 001: Metric: 61.43 002: Metric: 81.64 004: Metric: 67.92 008: Metric: 51.67 016: Metric: 50.47 032: Metric: 52.29 064: Metric: 50.01 128: Metric: 49.04 So for low threads, it's not restored but for larger number of threads, it's closer to the "known good" baseline. Using a different mremap-intensive workload that is not representative of the real workload there is little difference observed outside of noise in the headline metrics However, the TLB shootdowns are reduced by 11% on average and at the peak, TLB shootdowns were reduced by 21%. Interrupts were sampled every second while the workload ran to get those figures. It's known that the figures will vary as the non-representative load is non-deterministic. An alternative patch was posted that should have significantly reduced the TLB flushes but unfortunately it does not perform as well as this version on the customer test case. If revisited, the two patches can stack on top of each other. Link: http://lkml.kernel.org/r/20180606183803.k7qaw2xnbvzshv34@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Aaron Lu <aaron.lu@intel.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-08mm: thp: check pmd migration entry in common pathZi Yan
When THP migration is being used, memory management code needs to handle pmd migration entries properly. This patch uses !pmd_present() or is_swap_pmd() (depending on whether pmd_none() needs separate code or not) to check pmd migration entries at the places where a pmd entry is present. Since pmd-related code uses split_huge_page(), split_huge_pmd(), pmd_trans_huge(), pmd_trans_unstable(), or pmd_none_or_trans_huge_or_clear_bad(), this patch: 1. adds pmd migration entry split code in split_huge_pmd(), 2. takes care of pmd migration entries whenever pmd_trans_huge() is present, 3. makes pmd_none_or_trans_huge_or_clear_bad() pmd migration entry aware. Since split_huge_page() uses split_huge_pmd() and pmd_trans_unstable() is equivalent to pmd_none_or_trans_huge_or_clear_bad(), we do not change them. Until this commit, a pmd entry should be: 1. pointing to a pte page, 2. is_swap_pmd(), 3. pmd_trans_huge(), 4. pmd_devmap(), or 5. pmd_none(). Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Nellans <dnellans@nvidia.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-06mm/mremap: fail map duplication attempts for private mappingsMike Kravetz
mremap will attempt to create a 'duplicate' mapping if old_size == 0 is specified. In the case of private mappings, mremap will actually create a fresh separate private