[PATCH] mm: compound release fix
Compound pages on SMP systems can now often be freed from pagetables via the release_pages path. This uses put_page_testzero which does not handle compound pages at all. Releasing constituent pages from process mappings decrements their count to a large negative number and leaks the reference at the head page - net result is a memory leak. The problem was hidden because the debug check in put_page_testzero itself actually did take compound pages into consideration. Fix the bug and the debug check. Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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