From 9de6886ec6e37f45807266a702bb7621498395ad Mon Sep 17 00:00:00 2001 From: Nicolas Pitre 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 Acked-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- 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; -- 2.20.1