From a190887b58c32d19c2eee007c5eb8faa970a69ba Mon Sep 17 00:00:00 2001 From: David Howells Date: Sat, 5 Sep 2009 11:17:07 -0700 Subject: [PATCH] nommu: fix error handling in do_mmap_pgoff() Fix the error handling in do_mmap_pgoff(). If do_mmap_shared_file() or do_mmap_private() fail, we jump to the error_put_region label at which point we cann __put_nommu_region() on the region - but we haven't yet added the region to the tree, and so __put_nommu_region() may BUG because the region tree is empty or it may corrupt the region tree. To get around this, we can afford to add the region to the region tree before calling do_mmap_shared_file() or do_mmap_private() as we keep nommu_region_sem write-locked, so no-one can race with us by seeing a transient region. Signed-off-by: David Howells Acked-by: Pekka Enberg Acked-by: Paul Mundt Cc: Mel Gorman Acked-by: Greg Ungerer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/nommu.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/mm/nommu.c b/mm/nommu.c index 4bde489ec431..66e81e7e9fe9 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1352,6 +1352,7 @@ unsigned long do_mmap_pgoff(struct file *file, } vma->vm_region = region; + add_nommu_region(region); /* set up the mapping */ if (file && vma->vm_flags & VM_SHARED) @@ -1361,8 +1362,6 @@ unsigned long do_mmap_pgoff(struct file *file, if (ret < 0) goto error_put_region; - add_nommu_region(region); - /* okay... we have a mapping; now we have to register it */ result = vma->vm_start; -- 2.39.2