path: root/mm
diff options
authorWeijie Yang <weijie.yang@samsung.com>2013-10-16 13:46:54 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-10-16 21:35:52 -0700
commitaa9bca05a467c61dcea4142b2877d5392de5bdce (patch)
treead269fed4d1f2f3c40e3adab9ea46162ebf59fe9 /mm
parente9cdd6e771580e6ff872e5c64e8b766972c7d1bc (diff)
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@samsung.com> Reviewed-by: Bob Liu <bob.liu@oracle.com> Cc: Minchan Kim <minchan@kernel.org> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: <stable@vger.kernel.org> From: Weijie Yang <weijie.yang@samsung.com> 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 <weijie.yang@samsung.com> Reviewed-by: Bob Liu <bob.liu@oracle.com> Cc: Minchan Kim <minchan@kernel.org> Cc: <stable@vger.kernel.org> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
1 files changed, 4 insertions, 0 deletions
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;
+ zbud_destroy_pool(tree->pool);
+ kfree(tree);
+ zswap_trees[type] = NULL;
static struct zbud_ops zswap_zbud_ops = {