From 251ebc7bb45c7e27b8868b13fb56fedeedfc1da4 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 23 Feb 2012 13:50:35 +0000 Subject: 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 Signed-off-by: David Howells Acked-by: Al Viro Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/nommu.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'mm') 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; } -- cgit v1.2.3