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authorDavid Howells <dhowells@redhat.com>2009-09-05 11:17:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-05 11:30:42 -0700
commita190887b58c32d19c2eee007c5eb8faa970a69ba (patch)
treedeff588d04f3e42662484b0281e1beceb3cf9f4e /mm/nommu.c
parent4e49627b9bc29a14b393c480e8c979e3bc922ef7 (diff)
downloadvexpress-lsk-a190887b58c32d19c2eee007c5eb8faa970a69ba.tar.gz
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 <dhowells@redhat.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Paul Mundt <lethal@linux-sh.org> Cc: Mel Gorman <mel@csn.ul.ie> Acked-by: Greg Ungerer <gerg@snapgear.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/nommu.c')
-rw-r--r--mm/nommu.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/mm/nommu.c b/mm/nommu.c
index 4bde489ec43..66e81e7e9fe 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;