Messages in this thread Patch in this message |  | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.11 55/66] mm/zswap: bugfix: memory leak when re-swapon | Date | Fri, 1 Nov 2013 15:07:31 -0700 |
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3.11-stable review patch. If anyone has any objections, please let me know.
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From: Weijie Yang <weijie.yang@samsung.com>
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: [PATCH 3.11 55/66] 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>
--- mm/zswap.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/mm/zswap.c +++ b/mm/zswap.c @@ -816,6 +816,10 @@ 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 = {
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