Subject: [merged] mm-zswap-bugfix-memory-leak-when-re-swapon.patch removed from -mm tree To: weijie.yang@xxxxxxxxxxx,bob.liu@xxxxxxxxxx,minchan@xxxxxxxxxx,sjenning@xxxxxxxxxxxxxxxxxx,stable@xxxxxxxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Thu, 17 Oct 2013 11:13:09 -0700 The patch titled Subject: mm/zswap: bugfix: memory leak when re-swapon has been removed from the -mm tree. Its filename was mm-zswap-bugfix-memory-leak-when-re-swapon.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Weijie Yang <weijie.yang@xxxxxxxxxxx> Subject: 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 <weijie.yang@xxxxxxxxxxx> Reviewed-by: Bob Liu <bob.liu@xxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Reviewed-by: Minchan Kim <minchan@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> From: Weijie Yang <weijie.yang@xxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxx: coding-style fixes] Signed-off-by: Weijie Yang <weijie.yang@xxxxxxxxxxx> Reviewed-by: Bob Liu <bob.liu@xxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Acked-by: Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/zswap.c | 4 ++++ 1 file changed, 4 insertions(+) diff -puN mm/zswap.c~mm-zswap-bugfix-memory-leak-when-re-swapon mm/zswap.c --- a/mm/zswap.c~mm-zswap-bugfix-memory-leak-when-re-swapon +++ a/mm/zswap.c @@ -804,6 +804,10 @@ 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 = { _ Patches currently in -mm which might be from weijie.yang@xxxxxxxxxxx are origin.patch mm-zswap-avoid-unnecessary-page-scanning.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html