Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760653Ab3DBM5K (ORCPT ); Tue, 2 Apr 2013 08:57:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13066 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760447Ab3DBM5J (ORCPT ); Tue, 2 Apr 2013 08:57:09 -0400 Date: Tue, 2 Apr 2013 18:27:00 +0530 (IST) From: P J P X-X-Sender: pjp@javelin.pnq.redhat.com To: linux-kernel@vger.kernel.org cc: linux-fsdevel@vger.kernel.org, Petr Matousek Subject: [PATCH] To add NULL pointer check Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1472 Lines: 47 Hello, 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 The patch below adds a NULL pointer check, from generic_writepages(), to avoid a possible NULL pointer dereference, in case if - mapping->a_ops->writepage - is NULL. === $ git diff diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 7bd22a2..9841372 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -550,9 +550,16 @@ redirty_out: static int __f2fs_writepage(struct page *page, struct writeback_control *wbc, void *data) { + int ret = 0; struct address_space *mapping = data; - int ret = mapping->a_ops->writepage(page, wbc); + + /* deal with chardevs and other special file */ + if (!mapping->a_ops->writepage) + return ret; + + ret = mapping->a_ops->writepage(page, wbc); mapping_set_error(mapping, ret); + return ret; } === Thank you. -- Prasad J Pandit / Red Hat Security Response Team DB7A 84C5 D3F9 7CD1 B5EB C939 D048 7860 3655 602B -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/