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3e43e260f1
Right now these are performed in kernel/fork.c which is odd and a violation of separation of concerns, as well as preventing us from integrating this and related logic into userland VMA testing going forward. There is a fly in the ointment - nommu - mmap.c is not compiled if CONFIG_MMU not set, and neither is vma.c. To square the circle, let's add a new file - vma_init.c. This will be compiled for both CONFIG_MMU and nommu builds, and will also form part of the VMA userland testing. This allows us to de-duplicate code, while maintaining separation of concerns and the ability for us to userland test this logic. Update the VMA userland tests accordingly, additionally adding a detach_free_vma() helper function to correctly detach VMAs before freeing them in test code, as this change was triggering the assert for this. [akpm@linux-foundation.org: remove stray newline, per Liam] Link: https://lkml.kernel.org/r/f97b3a85a6da0196b28070df331b99e22b263be8.1745853549.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Pedro Falcato <pfalcato@suse.de> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Kees Cook <kees@kernel.org> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
102 lines
2.6 KiB
C
102 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Functions for initialisaing, allocating, freeing and duplicating VMAs. Shared
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* between CONFIG_MMU and non-CONFIG_MMU kernel configurations.
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*/
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#include "vma_internal.h"
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#include "vma.h"
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/* SLAB cache for vm_area_struct structures */
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static struct kmem_cache *vm_area_cachep;
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void __init vma_state_init(void)
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{
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struct kmem_cache_args args = {
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.use_freeptr_offset = true,
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.freeptr_offset = offsetof(struct vm_area_struct, vm_freeptr),
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};
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vm_area_cachep = kmem_cache_create("vm_area_struct",
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sizeof(struct vm_area_struct), &args,
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SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_TYPESAFE_BY_RCU|
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SLAB_ACCOUNT);
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}
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struct vm_area_struct *vm_area_alloc(struct mm_struct *mm)
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{
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struct vm_area_struct *vma;
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vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
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if (!vma)
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return NULL;
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vma_init(vma, mm);
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return vma;
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}
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static void vm_area_init_from(const struct vm_area_struct *src,
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struct vm_area_struct *dest)
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{
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dest->vm_mm = src->vm_mm;
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dest->vm_ops = src->vm_ops;
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dest->vm_start = src->vm_start;
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dest->vm_end = src->vm_end;
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dest->anon_vma = src->anon_vma;
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dest->vm_pgoff = src->vm_pgoff;
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dest->vm_file = src->vm_file;
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dest->vm_private_data = src->vm_private_data;
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vm_flags_init(dest, src->vm_flags);
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memcpy(&dest->vm_page_prot, &src->vm_page_prot,
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sizeof(dest->vm_page_prot));
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/*
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* src->shared.rb may be modified concurrently when called from
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* dup_mmap(), but the clone will reinitialize it.
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*/
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data_race(memcpy(&dest->shared, &src->shared, sizeof(dest->shared)));
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memcpy(&dest->vm_userfaultfd_ctx, &src->vm_userfaultfd_ctx,
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sizeof(dest->vm_userfaultfd_ctx));
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#ifdef CONFIG_ANON_VMA_NAME
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dest->anon_name = src->anon_name;
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#endif
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#ifdef CONFIG_SWAP
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memcpy(&dest->swap_readahead_info, &src->swap_readahead_info,
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sizeof(dest->swap_readahead_info));
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#endif
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#ifndef CONFIG_MMU
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dest->vm_region = src->vm_region;
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#endif
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#ifdef CONFIG_NUMA
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dest->vm_policy = src->vm_policy;
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#endif
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}
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struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
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{
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struct vm_area_struct *new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
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if (!new)
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return NULL;
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ASSERT_EXCLUSIVE_WRITER(orig->vm_flags);
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ASSERT_EXCLUSIVE_WRITER(orig->vm_file);
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vm_area_init_from(orig, new);
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vma_lock_init(new, true);
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INIT_LIST_HEAD(&new->anon_vma_chain);
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vma_numab_state_init(new);
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dup_anon_vma_name(orig, new);
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return new;
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}
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void vm_area_free(struct vm_area_struct *vma)
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{
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/* The vma should be detached while being destroyed. */
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vma_assert_detached(vma);
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vma_numab_state_free(vma);
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free_anon_vma_name(vma);
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kmem_cache_free(vm_area_cachep, vma);
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}
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