From: Weijie Yang Date: Wed, 16 Oct 2013 20:46:54 +0000 (-0700) Subject: mm/zswap: bugfix: memory leak when re-swapon X-Git-Tag: v3.12-rc6~11^2~12 X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=aa9bca05a467c61dcea4142b2877d5392de5bdce;p=~emulex%2Finfiniband.git mm/zswap: bugfix: memory leak when re-swapon 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 Reviewed-by: Bob Liu Cc: Minchan Kim Reviewed-by: Minchan Kim Cc: From: Weijie Yang Subject: mm/zswap: bugfix: memory leak when invalidate and reclaim occur concurrently 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. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Weijie Yang Reviewed-by: Bob Liu Cc: Minchan Kim Cc: Acked-by: Seth Jennings Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/zswap.c b/mm/zswap.c index 841e35f1db2..d93510c6aa2 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -804,6 +804,10 @@ static void zswap_frontswap_invalidate_area(unsigned type) } 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 = {