Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 28 Mar 2002 02:32:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 28 Mar 2002 02:32:19 -0500 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:7433 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id ; Thu, 28 Mar 2002 02:32:04 -0500 Message-ID: <3CA2C68E.5B8C4176@zip.com.au> Date: Wed, 27 Mar 2002 23:30:22 -0800 From: Andrew Morton X-Mailer: Mozilla 4.79 [en] (X11; U; Linux 2.4.19-pre4 i686) X-Accept-Language: en MIME-Version: 1.0 To: lkml , Linus Torvalds Subject: [patch] ext2_fill_super breakage Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org In 2.5.7 there is a thinko in the allocation and initialisation of the fs-private superblock for ext2. It's passing the wrong type to the sizeof operator (which of course gives the wrong size) when allocating and clearing the memory. Lesson for the day: this is one of the reasons why this idiom: some_type *p; p = malloc(sizeof(*p)); ... memset(p, 0, sizeof(*p)); is preferable to some_type *p; p = malloc(sizeof(some_type)); ... memset(p, 0, sizeof(some_type)); I checked the other filesystems. They're OK (but idiomatically impure). I've added a couple of defensive memsets where they were missing. --- 2.5.7/fs/autofs/inode.c~fill-super Wed Mar 27 23:14:20 2002 +++ 2.5.7-akpm/fs/autofs/inode.c Wed Mar 27 23:14:54 2002 @@ -119,9 +119,10 @@ int autofs_fill_super(struct super_block struct autofs_sb_info *sbi; int minproto, maxproto; - sbi = (struct autofs_sb_info *) kmalloc(sizeof(struct autofs_sb_info), GFP_KERNEL); + sbi = kmalloc(sizeof(*sbi), GFP_KERNEL); if ( !sbi ) goto fail_unlock; + memset(sbi, 0, sizeof(*sbi)); DPRINTK(("autofs: starting up, sbi = %p\n",sbi)); s->u.generic_sbp = sbi; --- 2.5.7/fs/devpts/inode.c~fill-super Wed Mar 27 23:16:05 2002 +++ 2.5.7-akpm/fs/devpts/inode.c Wed Mar 27 23:16:33 2002 @@ -123,9 +123,10 @@ static int devpts_fill_super(struct supe struct inode * inode; struct devpts_sb_info *sbi; - sbi = (struct devpts_sb_info *) kmalloc(sizeof(struct devpts_sb_info), GFP_KERNEL); + sbi = kmalloc(sizeof(*sbi), GFP_KERNEL); if ( !sbi ) goto fail; + memset(sbi, 0, sizeof(*sbi)); sbi->magic = DEVPTS_SBI_MAGIC; sbi->max_ptys = unix98_max_ptys; --- 2.5.7/fs/ext2/super.c~fill-super Wed Mar 27 23:16:57 2002 +++ 2.5.7-akpm/fs/ext2/super.c Wed Mar 27 23:17:25 2002 @@ -465,11 +465,11 @@ static int ext2_fill_super(struct super_ int db_count; int i, j; - sbi = kmalloc(sizeof(struct ext2_super_block), GFP_KERNEL); + sbi = kmalloc(sizeof(*sbi), GFP_KERNEL); if (!sbi) return -ENOMEM; sb->u.generic_sbp = sbi; - memset(sbi, 0, sizeof(struct ext2_super_block)); + memset(sbi, 0, sizeof(*sbi)); /* * See what the current blocksize for the device is, and - - 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/