From cfb185a1488810fbae9256c7d52f66c558c6ea04 Mon Sep 17 00:00:00 2001 From: P J P Date: Wed, 3 Apr 2013 11:38:00 +0900 Subject: [PATCH] f2fs: add NULL pointer check Commit - fa9150a84c - replaces a call to generic_writepages() in f2fs_write_data_pages() with write_cache_pages(), with a function pointer argument pointing to routine: __f2fs_writepage. -> https://git.kernel.org/linus/fa9150a84ca333f68127097c4fa1eda4b3913a22 This patch adds a NULL pointer check in f2fs_write_data_pages() to avoid a possible NULL pointer dereference, in case if - mapping->a_ops->writepage - is NULL. Signed-off-by: P J P Signed-off-by: Jaegeuk Kim --- fs/f2fs/data.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 47a2d7c..cf9ff5f 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -559,6 +559,10 @@ static int f2fs_write_data_pages(struct address_space *mapping, int ret; long excess_nrtw = 0, desired_nrtw; + /* deal with chardevs and other special file */ + if (!mapping->a_ops->writepage) + return 0; + if (wbc->nr_to_write < MAX_DESIRED_PAGES_WP) { desired_nrtw = MAX_DESIRED_PAGES_WP; excess_nrtw = desired_nrtw - wbc->nr_to_write; -- 2.7.4