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| author | David Howells <dhowells@redhat.com> | 2012-02-23 13:50:35 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-02-29 16:33:36 -0800 |
| commit | 251ebc7bb45c7e27b8868b13fb56fedeedfc1da4 (patch) | |
| tree | b633573d388a5c3c8d4e610d00c8decb0bdee2fc | |
| parent | 62797c459126d343df0e9095fe1aa9ae3ebb3f89 (diff) | |
| download | lwn-251ebc7bb45c7e27b8868b13fb56fedeedfc1da4.tar.gz lwn-251ebc7bb45c7e27b8868b13fb56fedeedfc1da4.zip | |
NOMMU: Lock i_mmap_mutex for access to the VMA prio list
commit 918e556ec214ed2f584e4cac56d7b29e4bb6bf27 upstream.
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 9edc897a3970..839775875e7f 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -697,9 +697,11 @@ 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 */ @@ -761,9 +763,11 @@ 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 */ @@ -2061,6 +2065,7 @@ 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, @@ -2068,6 +2073,7 @@ 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 */ } @@ -2095,6 +2101,7 @@ 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; } |