From 9de6886ec6e37f45807266a702bb7621498395ad Mon Sep 17 00:00:00 2001
From: Nicolas Pitre <nico@cam.org>
Date: Sat, 5 Sep 2009 00:25:37 -0400
Subject: [PATCH] ext2: fix unbalanced kmap()/kunmap()
In ext2_rename(), dir_page is acquired through ext2_dotdot(). It is
then released through ext2_set_link() but only if old_dir != new_dir.
Failing that, the pkmap reference count is never decremented and the
page remains pinned forever. Repeat that a couple times with highmem
pages and all pkmap slots get exhausted, and every further kmap() calls
end up stalling on the pkmap_map_wait queue at which point the whole
system comes to a halt.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/ext2/namei.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index e1dedb0f7873..78d9b925fc94 100644
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -362,6 +362,10 @@ static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
if (dir_de) {
if (old_dir != new_dir)
ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0);
+ else {
+ kunmap(dir_page);
+ page_cache_release(dir_page);
+ }
inode_dec_link_count(old_dir);
}
return 0;
--
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