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| author | David Howells <dhowells@redhat.com> | 2012-02-23 13:50:35 +0000 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-02-24 08:59:04 -0800 |
| commit | 918e556ec214ed2f584e4cac56d7b29e4bb6bf27 (patch) | |
| tree | cf2ba7c88f4b349d1120517f09ec4588f12eb285 | |
| parent | 37e79cbf7d45451fb4d1213184e484723c25c65a (diff) | |
| download | linux-918e556ec214ed2f584e4cac56d7b29e4bb6bf27.tar.gz linux-918e556ec214ed2f584e4cac56d7b29e4bb6bf27.tar.bz2 linux-918e556ec214ed2f584e4cac56d7b29e4bb6bf27.zip | |
NOMMU: Lock i_mmap_mutex for access to the VMA prio list
Lock i_mmap_mutex for access to the VMA prio list to prevent concurrent
access. Currently, certain parts of the mmap handling are protected by
the region mutex, but not all.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/nommu.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/mm/nommu.c b/mm/nommu.c index b982290fd962..ee7e57ebef6a 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -696,9 +696,11 @@ static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma) if (vma->vm_file) { mapping = vma->vm_file->f_mapping; + mutex_lock(&mapping->i_mmap_mutex); flush_dcache_mmap_lock(mapping); vma_prio_tree_insert(vma, &mapping->i_mmap); flush_dcache_mmap_unlock(mapping); + mutex_unlock(&mapping->i_mmap_mutex); } /* add the VMA to the tree */ @@ -760,9 +762,11 @@ static void delete_vma_from_mm(struct vm_area_struct *vma) if (vma->vm_file) { mapping = vma->vm_file->f_mapping; + mutex_lock(&mapping->i_mmap_mutex); flush_dcache_mmap_lock(mapping); vma_prio_tree_remove(vma, &mapping->i_mmap); flush_dcache_mmap_unlock(mapping); + mutex_unlock(&mapping->i_mmap_mutex); } /* remove from the MM's tree and list */ @@ -2052,6 +2056,7 @@ int nommu_shrink_inode_mappings(struct inode *inode, size_t size, high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; down_write(&nommu_region_sem); + mutex_lock(&inode->i_mapping->i_mmap_mutex); /* search for VMAs that fall within the dead zone */ vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap, @@ -2059,6 +2064,7 @@ int nommu_shrink_inode_mappings(struct inode *inode, size_t size, /* found one - only interested if it's shared out of the page * cache */ if (vma->vm_flags & VM_SHARED) { + mutex_unlock(&inode->i_mapping->i_mmap_mutex); up_write(&nommu_region_sem); return -ETXTBSY; /* not quite true, but near enough */ } @@ -2086,6 +2092,7 @@ int nommu_shrink_inode_mappings(struct inode *inode, size_t size, } } + mutex_unlock(&inode->i_mapping->i_mmap_mutex); up_write(&nommu_region_sem); return 0; } |