From: Nicolas Pitre Date: Sat, 5 Sep 2009 04:25:37 +0000 (-0400) Subject: ext2: fix unbalanced kmap()/kunmap() X-Git-Tag: MMI-PSA29.97-13-9~27042 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=9de6886ec6e37f45807266a702bb7621498395ad;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git 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 --- 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;