From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx133.postini.com [74.125.245.133]) by kanga.kvack.org (Postfix) with SMTP id 0B9206B004A for ; Thu, 23 Feb 2012 08:50:44 -0500 (EST) From: David Howells Subject: [PATCH 1/3] NOMMU: Lock i_mmap_mutex for access to the VMA prio list Date: Thu, 23 Feb 2012 13:50:35 +0000 Message-ID: <20120223135035.24278.96099.stgit@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: torvalds@linux-foundation.org Cc: linux-mm@kvack.org, uclinux-dev@uclinux.org, gerg@uclinux.org, lethal@linux-sh.org, David Howells , Al Viro , stable@vger.kernel.org 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 cc: stable@vger.kernel.org --- mm/nommu.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-) diff --git a/mm/nommu.c b/mm/nommu.c index b982290..ee7e57e 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; } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org