This is a note to let you know that I've just added the patch titled
mm/zswap: bugfix: memory leak when re-swapon
mm/zswap: bugfix: memory leak when invalidate and reclaim occur concurrently
to the 3.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-zswap-bugfix-memory-leak-when-re-swapon.patch
and it can be found in the queue-3.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From aa9bca05a467c61dcea4142b2877d5392de5bdce Mon Sep 17 00:00:00 2001
From: Weijie Yang <[email protected]>
Date: Wed, 16 Oct 2013 13:46:54 -0700
Subject: mm/zswap: bugfix: memory leak when re-swapon
From: Weijie Yang <[email protected]>
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 <[email protected]>
Reviewed-by: Bob Liu <[email protected]>
Cc: Minchan Kim <[email protected]>
Reviewed-by: Minchan Kim <[email protected]>
From: Weijie Yang <[email protected]>
Subject: mm/zswap: bugfix: memory leak when invalidate and reclaim occur
concurrently
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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.
[[email protected]: coding-style fixes]
Signed-off-by: Weijie Yang <[email protected]>
Reviewed-by: Bob Liu <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: <[email protected]>
Acked-by: Seth Jennings <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
---
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 = {
Patches currently in stable-queue which might be from [email protected]
are
queue-3.11/mm-zswap-bugfix-memory-leak-when-re-swapon.patch
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