diff options
| author | Weijie Yang <weijie.yang@samsung.com> | 2013-10-16 13:46:54 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-11-04 04:35:20 -0800 |
| commit | 4e31a0e20aa1788668b0322396c0e16e06b302da (patch) | |
| tree | 67544ae5fc5d2f118c89bb637ca60a5746f8106d | |
| parent | 72d2ddf5f2218861f41b7d1a9da4c130d6d81911 (diff) | |
mm/zswap: bugfix: memory leak when re-swapon
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 <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>
From: Weijie Yang <weijie.yang@samsung.com>
Subject: mm/zswap: bugfix: memory leak when invalidate and reclaim occur concurrently
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
| -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 deda2b671e12..cbd9578c1e88 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -816,6 +816,10 @@ 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 = { |