From a1ee5a45818acc7f9c13e560827cf3e8735ac919 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 9 Jan 2012 14:27:42 +0800 Subject: [PATCH] Btrfs: avoid possible NULL deref in io_ctl_drop_pages() If we run into some failure path in io_ctl_prepare_pages(), io_ctl->pages[] array may have some NULL pointers. Signed-off-by: Li Zefan --- fs/btrfs/free-space-cache.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index 01840ef95a32..4e55af333e19 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -319,9 +319,11 @@ static void io_ctl_drop_pages(struct io_ctl *io_ctl) io_ctl_unmap_page(io_ctl); for (i = 0; i < io_ctl->num_pages; i++) { - ClearPageChecked(io_ctl->pages[i]); - unlock_page(io_ctl->pages[i]); - page_cache_release(io_ctl->pages[i]); + if (io_ctl->pages[i]) { + ClearPageChecked(io_ctl->pages[i]); + unlock_page(io_ctl->pages[i]); + page_cache_release(io_ctl->pages[i]); + } } }