Eric Lee / smarc-ti-linux-kernel

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Commit a190887b58c32d19c2eee007c5eb8faa970a69ba

Authored by David Howells
Committed by Linus Torvalds
1 parent 4e49627b9b

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>

Showing 1 changed file with 1 additions and 2 deletions Side-by-side Diff

... ... @@ -1352,6 +1352,7 @@
1352 1352 }
1353 1353  
1354 1354 vma->vm_region = region;
  1355 + add_nommu_region(region);
1355 1356  
1356 1357 /* set up the mapping */
1357 1358 if (file && vma->vm_flags & VM_SHARED)
... ... @@ -1360,8 +1361,6 @@
1360 1361 ret = do_mmap_private(vma, region, len);
1361 1362 if (ret < 0)
1362 1363 goto error_put_region;
1363   -
1364   - add_nommu_region(region);
1365 1364  
1366 1365 /* okay... we have a mapping; now we have to register it */
1367 1366 result = vma->vm_start;