3.11-stable review patch. If anyone has any objections, please let me know.
------------------ From: Weijie Yang <[email protected]> commit aa9bca05a467c61dcea4142b2877d5392de5bdce upstream. zswap_tree is not freed when swapoff, and it got re-kmalloced in swapon, so a memory leak occurs. Free the memory of zswap_tree in zswap_frontswap_invalidate_area(). Signed-off-by: Weijie Yang <[email protected]> Reviewed-by: Bob Liu <[email protected]> Cc: Minchan Kim <[email protected]> Reviewed-by: Minchan Kim <[email protected]> From: Weijie Yang <[email protected]> Subject: [PATCH 3.11 55/66] mm/zswap: bugfix: memory leak when invalidate and reclaim occur concurrently Signed-off-by: Greg Kroah-Hartman <[email protected]> Consider the following scenario: thread 0: reclaim entry x (get refcount, but not call zswap_get_swap_cache_page) thread 1: call zswap_frontswap_invalidate_page to invalidate entry x. finished, entry x and its zbud is not freed as its refcount != 0 now, the swap_map[x] = 0 thread 0: now call zswap_get_swap_cache_page swapcache_prepare return -ENOENT because entry x is not used any more zswap_get_swap_cache_page return ZSWAP_SWAPCACHE_NOMEM zswap_writeback_entry do nothing except put refcount Now, the memory of zswap_entry x and its zpage leak. Modify: - check the refcount in fail path, free memory if it is not referenced. - use ZSWAP_SWAPCACHE_FAIL instead of ZSWAP_SWAPCACHE_NOMEM as the fail path can be not only caused by nomem but also by invalidate. [[email protected]: coding-style fixes] Signed-off-by: Weijie Yang <[email protected]> Reviewed-by: Bob Liu <[email protected]> Cc: Minchan Kim <[email protected]> Cc: <[email protected]> Acked-by: Seth Jennings <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> --- mm/zswap.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/mm/zswap.c +++ b/mm/zswap.c @@ -816,6 +816,10 @@ static void zswap_frontswap_invalidate_a } tree->rbroot = RB_ROOT; spin_unlock(&tree->lock); + + zbud_destroy_pool(tree->pool); + kfree(tree); + zswap_trees[type] = NULL; } static struct zbud_ops zswap_zbud_ops = { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
