diff options
author | Weijie Yang <weijie.yang@samsung.com> | 2013-10-16 13:46:54 -0700 |
---|---|---|
committer | Chanho Park <chanho61.park@samsung.com> | 2014-03-20 17:44:41 +0900 |
commit | cb59860ea517e83f80827ce19e725fe955a29c64 (patch) | |
tree | 4676e7ba98d2ca83ef56d9807a8a978071192252 | |
parent | 40007d6213705ab86bb55fc557342caca6b7eb8c (diff) | |
download | linux-3.10-cb59860ea517e83f80827ce19e725fe955a29c64.tar.gz linux-3.10-cb59860ea517e83f80827ce19e725fe955a29c64.tar.bz2 linux-3.10-cb59860ea517e83f80827ce19e725fe955a29c64.zip |
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>
Change-Id: I4a875e48714d73bf2c1f75b60d90776365c047de
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | mm/zswap.c | 4 |
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; spin_unlock(&tree->lock); + + zbud_destroy_pool(tree->pool); + kfree(tree); + zswap_trees[type] = NULL; } static struct zbud_ops zswap_zbud_ops = { |