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2019-12-01mm: fix typos in comments when calling __SetPageUptodate()Wei Yang1-1/+1
There are several places emphasise the effect of __SetPageUptodate(), while the comment seems to have a typo in two places. Link: http://lkml.kernel.org/r/20190926023705.7226-1-richardw.yang@linux.intel.com Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01userfaultfd: wrap the common dst_vma check into an inlined functionWei Yang1-24/+32
When doing UFFDIO_COPY, it is necessary to find the correct destination vma and make sure fault range is in it. Since there are two places need to do the same task, just wrap those common check into an inlined function. Link: http://lkml.kernel.org/r/20190927070032.2129-3-richardw.yang@linux.intel.com Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.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>
2019-12-01userfaultfd: remove unnecessary WARN_ON() in __mcopy_atomic_hugetlb()Wei Yang1-5/+0
These warning here is to make sure address(dst_addr) and length(len - copied) are huge page size aligned. While this is ensured by: dst_start and len is huge page size aligned dst_addr equals to dst_start and increase huge page size each time copied increase huge page size each time This means these warnings will never be triggered. Link: http://lkml.kernel.org/r/20190927070032.2129-2-richardw.yang@linux.intel.com Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.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>
2019-12-01userfaultfd: use vma_pagesize for all huge page size calculationWei Yang1-3/+4
In __mcopy_atomic_hugetlb() we use two variables to deal with huge page size: vma_hpagesize and huge_page_size. Since they are the same, it is not necessary to use two different mechanism. This patch makes it consistent by all using vma_hpagesize. Link: http://lkml.kernel.org/r/20190927070032.2129-1-richardw.yang@linux.intel.com Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.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>
2019-12-01hugetlb: remove unused hstate in hugetlb_fault_mutex_hash()Wei Yang1-4/+1
The first parameter hstate in function hugetlb_fault_mutex_hash() is not used anymore. This patch removes it. [akpm@linux-foundation.org: various build fixes] [cai@lca.pw: fix a GCC compilation warning] Link: http://lkml.kernel.org/r/1570544108-32331-1-git-send-email-cai@lca.pw Link: http://lkml.kernel.org/r/20191005003302.785-1-richardw.yang@linux.intel.com Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Signed-off-by: Qian Cai <cai@lca.pw> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01hugetlbfs: hugetlb_fault_mutex_hash() cleanupMike Kravetz1-1/+1
A new clang diagnostic (-Wsizeof-array-div) warns about the calculation to determine the number of u32's in an array of unsigned longs. Suppress warning by adding parentheses. While looking at the above issue, noticed that the 'address' parameter to hugetlb_fault_mutex_hash is no longer used. So, remove it from the definition and all callers. No functional change. Link: http://lkml.kernel.org/r/20190919011847.18400-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Ilie Halip <ilie.halip@gmail.com> Cc: David Bolvansky <david.bolvansky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 499Thomas Gleixner1-3/+1
Based on 1 normalized pattern(s): this work is licensed under the terms of the gnu gpl version 2 see the copying file in the top level directory extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 35 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.797835076@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14hugetlb: use same fault hash key for shared and private mappingsMike Kravetz1-2/+1
hugetlb uses a fault mutex hash table to prevent page faults of the same pages concurrently. The key for shared and private mappings is different. Shared keys off address_space and file index. Private keys off mm and virtual address. Consider a private mappings of a populated hugetlbfs file. A fault will map the page from the file and if needed do a COW to map a writable page. Hugetlbfs hole punch uses the fault mutex to prevent mappings of file pages. It uses the address_space file index key. However, private mappings will use a different key and could race with this code to map the file page. This causes problems (BUG) for the page cache remove code as it expects the page to be unmapped. A sample stack is: page dumped because: VM_BUG_ON_PAGE(page_mapped(page)) kernel BUG at mm/filemap.c:169! ... RIP: 0010:unaccount_page_cache_page+0x1b8/0x200 ... Call Trace: __delete_from_page_cache+0x39/0x220 delete_from_page_cache+0x45/0x70 remove_inode_hugepages+0x13c/0x380 ? __add_to_page_cache_locked+0x162/0x380 hugetlbfs_fallocate+0x403/0x540 ? _cond_resched+0x15/0x30 ? __inode_security_revalidate+0x5d/0x70 ? selinux_file_permission+0x100/0x130 vfs_fallocate+0x13f/0x270 ksys_fallocate+0x3c/0x80 __x64_sys_fallocate+0x1a/0x20 do_syscall_64+0x5b/0x180 entry_SYSCALL_64_after_hwframe+0x44/0xa9 There seems to be another potential COW issue/race with this approach of different private and shared keys as noted in commit 8382d914ebf7 ("mm, hugetlb: improve page-fault scalability"). Since every hugetlb mapping (even anon and private) is actually a file mapping, just use the address_space index key for all mappings. This results in potentially more hash collisions. However, this should not be the common case. Link: http://lkml.kernel.org/r/20190328234704.27083-3-mike.kravetz@oracle.com Link: http://lkml.kernel.org/r/20190412165235.t4sscoujczfhuiyt@linux-r8p5 Fixes: b5cec28d36f5 ("hugetlbfs: truncate_hugepages() takes a range of pages") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-08hugetlbfs: revert "use i_mmap_rwsem for more pmd sharing synchronization"Mike Kravetz1-9/+2
This reverts b43a9990055958e70347c56f90ea2ae32c67334c The reverted commit caused issues with migration and poisoning of anon huge pages. The LTP move_pages12 test will cause an "unable to handle kernel NULL pointer" BUG would occur with stack similar to: RIP: 0010:down_write+0x1b/0x40 Call Trace: migrate_pages+0x81f/0xb90 __ia32_compat_sys_migrate_pages+0x190/0x190 do_move_pages_to_node.isra.53.part.54+0x2a/0x50 kernel_move_pages+0x566/0x7b0 __x64_sys_move_pages+0x24/0x30 do_syscall_64+0x5b/0x180 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The purpose of the reverted patch was to fix some long existing races with huge pmd sharing. It used i_mmap_rwsem for this purpose with the idea that this could also be used to address truncate/page fault races with another patch. Further analysis has determined that i_mmap_rwsem can not be used to address all these hugetlbfs synchronization issues. Therefore, revert this patch while working an another approach to the underlying issues. Link: http://lkml.kernel.org/r/20190103235452.29335-2-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Jan Stancek <jstancek@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Prakash Sangappa <prakash.sangappa@oracle.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)1-1/+1
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>
2018-12-28hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronizationMike Kravetz1-2/+9
While looking at BUGs associated with invalid huge page map counts, it was discovered and observed that a huge pte pointer could become 'invalid' and point to another task's page table. Consider the following: A task takes a page fault on a shared hugetlbfs file and calls huge_pte_alloc to get a ptep. Suppose the returned ptep points to a shared pmd. Now, another task truncates the hugetlbfs file. As part of truncation, it unmaps everyone who has the file mapped. If the range being truncated is covered by a shared pmd, huge_pmd_unshare will be called. For all but the last user of the shared pmd, huge_pmd_unshare will clear the pud pointing to the pmd. If the task in the middle of the page fault is not the last user, the ptep returned by huge_pte_alloc now points to another task's page table or worse. This leads to bad things such as incorrect page map/reference counts or invalid memory references. To fix, expand the use of i_mmap_rwsem as follows: - i_mmap_rwsem is held in read mode whenever huge_pmd_share is called. huge_pmd_share is only called via huge_pte_alloc, so callers of huge_pte_alloc take i_mmap_rwsem before calling. In addition, callers of huge_pte_alloc continue to hold the semaphore until finished with the ptep. - i_mmap_rwsem is held in write mode whenever huge_pmd_unshare is called. [mike.kravetz@oracle.com: add explicit check for mapping != null] Link: http://lkml.kernel.org/r/20181218223557.5202-2-mike.kravetz@oracle.com Fixes: 39dde65c9940 ("shared page table for hugetlb page") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-11-30userfaultfd: shmem: add i_size checksAndrea Arcangeli1-2/+24
With MAP_SHARED: recheck the i_size after taking the PT lock, to serialize against truncate with the PT lock. Delete the page from the pagecache if the i_size_read check fails. With MAP_PRIVATE: check the i_size after the PT lock before mapping anonymous memory or zeropages into the MAP_PRIVATE shmem mapping. A mostly irrelevant cleanup: like we do the delete_from_page_cache() pagecache removal after dropping the PT lock, the PT lock is a spinlock so drop it before the sleepable page lock. Link: http://lkml.kernel.org/r/20181126173452.26955-5-aarcange@redhat.com Fixes: 4c27fe4c4c84 ("userfaultfd: shmem: add shmem_mcopy_atomic_pte for userfaultfd support") Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Hugh Dickins <hughd@google.com> Reported-by: Jann Horn <jannh@google.com> Cc: <stable@vger.kernel.org> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Peter Xu <peterx@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-11-30userfaultfd: shmem/hugetlbfs: only allow to register VM_MAYWRITE vmasAndrea Arcangeli1-9/+6
After the VMA to register the uffd onto is found, check that it has VM_MAYWRITE set before allowing registration. This way we inherit all common code checks before allowing to fill file holes in shmem and hugetlbfs with UFFDIO_COPY. The userfaultfd memory model is not applicable for readonly files unless it's a MAP_PRIVATE. Link: http://lkml.kernel.org/r/20181126173452.26955-4-aarcange@redhat.com Fixes: ff62a3421044 ("hugetlb: implement memfd sealing") Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Hugh Dickins <hughd@google.com> Reported-by: Jann Horn <jannh@google.com> Fixes: 4c27fe4c4c84 ("userfaultfd: shmem: add shmem_mcopy_atomic_pte for userfaultfd support") Cc: <stable@vger.kernel.org> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Peter Xu <peterx@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-11-30userfaultfd: shmem: allocate anonymous memory for MAP_PRIVATE shmemAndrea Arcangeli1-2/+13
Userfaultfd did not create private memory when UFFDIO_COPY was invoked on a MAP_PRIVATE shmem mapping. Instead it wrote to the shmem file, even when that had not been opened for writing. Though, fortunately, that could only happen where there was a hole in the file. Fix the shmem-backed implementation of UFFDIO_COPY to create private memory for MAP_PRIVATE mappings. The hugetlbfs-backed implementation was already correct. This change is visible to userland, if userfaultfd has been used in unintended ways: so it introduces a small risk of incompatibility, but is necessary in order to respect file permissions. An app that uses UFFDIO_COPY for anything like postcopy live migration won't notice the difference, and in fact it'll run faster because there will be no copy-on-write and memory waste in the tmpfs pagecache anymore. Userfaults on MAP_PRIVATE shmem keep triggering only on file holes like before. The real zeropage can also be built on a MAP_PRIVATE shmem mapping through UFFDIO_ZEROPAGE and that's safe because the zeropage pte is never dirty, in turn even an mprotect upgrading the vma permission from PROT_READ to PROT_READ|PROT_WRITE won't make the zeropage pte writable. Link: http://lkml.kernel.org/r/20181126173452.26955-3-aarcange@redhat.com Fixes: 4c27fe4c4c84 ("userfaultfd: shmem: add shmem_mcopy_atomic_pte for userfaultfd support") Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Peter Xu <peterx@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-11-30userfaultfd: use ENOENT instead of EFAULT if the atomic copy user failsAndrea Arcangeli1-3/+3
Patch series "userfaultfd shmem updates". Jann found two bugs in the userfaultfd shmem MAP_SHARED backend: the lack of the VM_MAYWRITE check and the lack of i_size checks. Then looking into the above we also fixed the MAP_PRIVATE case. Hugh by source review also found a data loss source if UFFDIO_COPY is used on shmem MAP_SHARED PROT_READ mappings (the production usages incidentally run with PROT_READ|PROT_WRITE, so the data loss couldn't happen in those production usages like with QEMU). The whole patchset is marked for stable. We verified QEMU postcopy live migration with guest running on shmem MAP_PRIVATE run as well as before after the fix of shmem MAP_PRIVATE. Regardless if it's shmem or hugetlbfs or MAP_PRIVATE or MAP_SHARED, QEMU unconditionally invokes a punch hole if the guest mapping is filebacked and a MADV_DONTNEED too (needed to get rid of the MAP_PRIVATE COWs and for the anon backend). This patch (of 5): We internally used EFAULT to communicate with the caller, switch to ENOENT, so EFAULT can be used as a non internal retval. Link: http://lkml.kernel.org/r/20181126173452.26955-2-aarcange@redhat.com Fixes: 4c27fe4c4c84 ("userfaultfd: shmem: add shmem_mcopy_atomic_pte for userfaultfd support") Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Hugh Dickins <hughd@google.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Jann Horn <jannh@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: <stable@vger.kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07userfaultfd: prevent non-cooperative events vs mcopy_atomic racesMike Rapoport1-5/+17
If a process monitored with userfaultfd changes it's memory mappings or forks() at the same time as uffd monitor fills the process memory with UFFDIO_COPY, the actual creation of page table entries and copying of the data in mcopy_atomic may happen either before of after the memory mapping modifications and there is no way for the uffd monitor to maintain consistent view of the process memory layout. For instance, let's consider fork() running in parallel with userfaultfd_copy(): process | uffd monitor ---------------------------------+------------------------------ fork() | userfaultfd_copy() ... | ... dup_mmap() | down_read(mmap_sem) down_write(mmap_sem) | /* create PTEs, copy data */ dup_uffd() | up_read(mmap_sem) copy_page_range() | up_write(mmap_sem) | dup_uffd_complete() | /* notify monitor */ | If the userfaultfd_copy() takes the mmap_sem first, the new page(s) will be present by the time copy_page_range() is called and they will appear in the child's memory mappings. However, if the fork() is the first to take the mmap_sem, the new pages won't be mapped in the child's address space. If the pages are not present and child tries to access them, the monitor will get page fault notification and everything is fine. However, if the pages *are present*, the child can access them without uffd noticing. And if we copy them into child it'll see the wrong data. Since we are talking about background copy, we'd need to decide whether the pages should be copied or not regardless #PF notifications. Since userfaultfd monitor has no way to determine what was the order, let's disallow userfaultfd_copy in parallel with the non-cooperative events. In such case we return -EAGAIN and the uffd monitor can understand that userfaultfd_copy() clashed with a non-cooperative event and take an appropriate action. Link: http://lkml.kernel.org/r/1527061324-19949-1-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Acked-by: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrei Vagin <avagin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-06mm/userfaultfd.c: remove duplicate includePravin Shedge1-1/+0
These duplicate includes have been found with scripts/checkincludes.pl but they have been removed manually to avoid removing false positives. Link: http://lkml.kernel.org/r/1512580957-6071-1-git-send-email-pravin.shedge4linux@gmail.com Signed-off-by: Pravin Shedge <pravin.shedge4linux@gmail.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>
2017-09-06userfaultfd: shmem: wire up shmem_mfill_zeropage_pteMike Rapoport1-2/+4
For shmem VMAs we can use shmem_mfill_zeropage_pte for UFFDIO_ZEROPAGE Link: http://lkml.kernel.org/r/1497939652-16528-6-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Hugh Dickins <hughd@google.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-06userfaultfd: mcopy_atomic: introduce mfill_atomic_pte helperMike Rapoport1-16/+30
Shuffle the code a bit to improve readability. Link: http://lkml.kernel.org/r/1497939652-16528-5-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Hugh Dickins <hughd@google.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09mm: convert generic code to 5-level pagingKirill A. Shutemov1-10/+13
Convert all non-architecture-specific code to 5-level paging. It's mostly mechanical adding handling one more page table level in places where we deal with pud_t. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-02sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h>Ingo Molnar1-0/+1
Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-24userfaultfd: mcopy_atomic: return -ENOENT when no compatible VMA foundMike Rapoport1-30/+28
The memory mapping of a process may change between #PF event and the call to mcopy_atomic that comes to resolve the page fault. In such case, there will be no VMA covering the range passed to mcopy_atomic or the VMA will not have userfaultfd context. To allow uffd monitor to distinguish those case from other errors, let's return -ENOENT instead of -EINVAL. Note, that despite availability of UFFD_EVENT_UNMAP there still might be race between the processing of UFFD_EVENT_UNMAP and outstanding mcopy_atomic in case of non-cooperative uffd usage. [rppt@linux.vnet.ibm.com: update cases returning -ENOENT] Link: http://lkml.kernel.org/r/20170207150249.GA6709@rapoport-lnx [aarcange@redhat.com: merge fix] [akpm@linux-foundation.org: fix the merge fix] Link: http://lkml.kernel.org/r/1485542673-24387-5-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-22userfaultfd: hugetlbfs: add UFFDIO_COPY support for shared mappingsMike Kravetz1-16/+58
When userfaultfd hugetlbfs support was originally added, it followed the pattern of anon mappings and did not support any vmas marked VM_SHARED. As such, support was only added for private mappings. Remove this limitation and support shared mappings. The primary functional change required is adding pages to the page cache. More subtle changes are required for huge page reservation handling in error paths. A lengthy comment in the code describes the reservation handling. [mike.kravetz@oracle.com: update] Link: http://lkml.kernel.org/r/c9c8cafe-baa7-05b4-34ea-1dfa5523a85f@oracle.com Link: http://lkml.kernel.org/r/1487195210-12839-1-git-send-email-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-22userfaultfd: shmem: use shmem_mcopy_atomic_pte for shared memoryMike Rapoport1-13/+21
The shmem_mcopy_atomic_pte implements low lever part of UFFDIO_COPY operation for shared memory VMAs. It's based on mcopy_atomic_pte with adjustments necessary for shared memory pages. Link: http://lkml.kernel.org/r/20161216144821.5183-32-aarcange@redhat.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Michael Rapoport <RAPOPORT@il.ibm.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-22userfaultfd: hugetlbfs: reserve count on error in __mcopy_atomic_hugetlbMike Kravetz1-1/+16
If __mcopy_atomic_hugetlb exits with an error, put_page will be called if a huge page was allocated and needs to be freed. If a reservation was associated with the huge page, the PagePrivate flag will be set. Clear PagePrivate before calling put_page/free_huge_page so that the global reservation count is not incremented. Link: http://lkml.kernel.org/r/20161216144821.5183-26-aarcange@redhat.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Michael Rapoport <RAPOPORT@il.ibm.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-22userfaultfd: hugetlbfs: fix __mcopy_atomic_hugetlb retry/error processingMike Kravetz1-1/+1
The new routine copy_huge_page_from_user() uses kmap_atomic() to map PAGE_SIZE pages. However, this prevents page faults in the subsequent call to copy_from_user(). This is OK in the case where the routine is copied with mmap_sema held. However, in another case we want to allow page faults. So, add a new argument allow_pagefault to indicate if the routine should allow page faults. [dan.carpenter@oracle.com: unmap the correct pointer] Link: http://lkml.kernel.org/r/20170113082608.GA3548@mwanda [akpm@linux-foundation.org: kunmap() takes a page*, per Hugh] Link: http://lkml.kernel.org/r/20161216144821.5183-20-aarcange@redhat.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Michael Rapoport <RAPOPORT@il.ibm.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Hugh Dickins <hughd@google.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>
2017-02-22userfaultfd: hugetlbfs: add __mcopy_atomic_hugetlb for huge page UFFDIO_COPYMike Kravetz1-0/+186
__mcopy_atomic_hugetlb performs the UFFDIO_COPY operation for huge pages. It is based on the existing __mcopy_atomic routine for normal pages. Unlike normal pages, there is no huge page support for the UFFDIO_ZEROPAGE operation. Link: http://lkml.kernel.org/r/20161216144821.5183-19-aarcange@redhat.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Michael Rapoport <RAPOPORT@il.ibm.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-22userfaultfd: use vma_is_anonymousAndrea Arcangeli1-1/+1
Cleanup the vma->vm_ops usage. Side note: it would be more robust if vma_is_anonymous() would also check that vm_flags hasn't VM_PFNMAP set. Link: http://lkml.kernel.org/r/20161216144821.5183-5-aarcange@redhat.com Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Michael Rapoport <RAPOPORT@il.ibm.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov1-2/+2
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17mm: cleanup *pte_alloc* interfacesKirill A. Shutemov1-2/+1
There are few things about *pte_alloc*() helpers worth cleaning up: - 'vma' argument is unused, let's drop it; - most __pte_alloc() callers do speculative check for pmd_none(), before taking ptl: let's introduce pte_alloc() macro which does the check. The only direct user of __pte_alloc left is userfaultfd, which has different expectation about atomicity wrt pmd. - pte_alloc_map() and pte_alloc_map_lock() are redefined using pte_alloc(). [sudeep.holla@arm.com: fix build for arm64 hugetlbpage] [sfr@canb.auug.org.au: fix arch/arm/mm/mmu.c some more] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15memcg: adjust to support new THP refcountingKirill A. Shutemov1-3/+3
As with rmap, with new refcounting we cannot rely on PageTransHuge() to check if we need to charge size of huge page form the cgroup. We need to get information from caller to know whether it was mapped with PMD or PTE. We do uncharge when last reference on the page gone. At that point if we see PageTransHuge() it means we need to unchange whole huge page. The tricky part is partial unmap -- when we try to unmap part of huge page. We don't do a special handing of this situation, meaning we don't uncharge the part of huge page unless last user is gone or split_huge_page() is triggered. In case of cgroup memory pressure happens the partial unmapped page will be split through shrinker. This should be good enough. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-15rmap: add argument to charge compound pageKirill A. Shutemov1-1/+1
We're going to allow mapping of individual 4k pages of THP compound page. It means we cannot rely on PageTransHuge() check to decide if map/unmap small page or THP. The patch adds new argument to rmap functions to indicate whether we want to operate on whole compound page or only the small page. [n-horiguchi@ah.jp.nec.com: fix mapcount mismatch in hugepage migration] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-04userfaultfd: avoid mmap_sem read recursion in mcopy_atomicAndrea Arcangeli1-26/+65
If the rwsem starves writers it wasn't strictly a bug but lockdep doesn't like it and this avoids depending on lowlevel implementation details of the lock. [akpm@linux-foundation.org: delete weird BUILD_BUG_ON()] Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-04userfaultfd: mcopy_atomic|mfill_zeropage: UFFDIO_COPY|UFFDIO_ZEROPAGE preparationAndrea Arcangeli1-0/+269
This implements mcopy_atomic and mfill_zeropage that are the lowlevel VM methods that are invoked respectively by the UFFDIO_COPY and UFFDIO_ZEROPAGE userfaultfd commands. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Pavel Emelyanov <xemul@parallels.com> Cc: Sanidhya Kashyap <sanidhya.gatech@gmail.com> Cc: zhang.zhanghailiang@huawei.com Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andres Lagar-Cavilla <andreslc@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Feiner <pfeiner@google.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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