Memory return to free_contig_range() must have no other references. Let kernel to complain loudly if page reference count is not equal to 1.
Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com Reviewed-by: Kyungmin Park kyungmin.park@samsung.com CC: Michal Nazarewicz mina86@mina86.com --- mm/page_alloc.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 022e4ed..290c2eb 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5888,8 +5888,13 @@ done:
void free_contig_range(unsigned long pfn, unsigned nr_pages) { - for (; nr_pages--; ++pfn) - __free_page(pfn_to_page(pfn)); + struct page *page = pfn_to_page(pfn); + int refcount = nr_pages; + for (; nr_pages--; page++) { + refcount -= page_count(page) == 1; + __free_page(page); + } + WARN(refcount != 0, "some pages are still in use!\n"); } #endif