From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754135Ab2GWI0c (ORCPT ); Mon, 23 Jul 2012 04:26:32 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44224 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754070Ab2GWI03 (ORCPT ); Mon, 23 Jul 2012 04:26:29 -0400 From: Steven Whitehouse To: linux-kernel@vger.kernel.org, cluster-devel@redhat.com Cc: Masatake YAMATO , Steven Whitehouse Subject: [PATCH 13/16] GFS2: Fixing double brelse'ing bh allocated in gfs2_meta_read when EIO occurs Date: Mon, 23 Jul 2012 09:01:03 +0100 Message-Id: <1343030466-3053-14-git-send-email-swhiteho@redhat.com> In-Reply-To: <1343030466-3053-1-git-send-email-swhiteho@redhat.com> References: <1343030466-3053-1-git-send-email-swhiteho@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Masatake YAMATO This patch fixes buffer_head double free in following code path: gfs2_block_map => gfs2_meta_inode_buffer => gfs2_meta_indirect_buffer => gfs2_meta_read => release_metapath gfs2_block_map calls gfs2_meta_inode_buffer with &mp.mp_bh[0] as an argument. mp.mp_bh are filled with zero at the beginning of gfs2_block_map. If gfs2_meta_inode_buffer returns non-zero value, gfs2_block_map calls release_metapath to free buffers chained to mp.mp_bh. release_metapath checks each slot of mp.mp_bh[i] and free(with brelse) unless the slot is filled with NULL. &mp.mp_bh[0] passed to gfs2_meta_inode_buffer is filled at gfs2_meta_read. gfs2_meta_read is filled a buffer allocated with gfs2_getbuf even if EIO occurs. When EIO occurs, the allocated buffer is brelse'ed though the pointer(wrong poiner) points the brelse'ed is passed back to caller via an argument bhp. gfs2_meta_indirect_buffer, the caller also pass the wrong pointer to its caller with EIO. Finally gfs2_block_map gets both EIO and &mp.mp_bh[0] filled with the wrong pointer. release_metapath calls brelse again on the wrong pointer. Signed-off-by: Masatake YAMATO Signed-off-by: Steven Whitehouse diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c index 6c1e5d1..3a56c8d 100644 --- a/fs/gfs2/meta_io.c +++ b/fs/gfs2/meta_io.c @@ -213,8 +213,10 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags, struct gfs2_sbd *sdp = gl->gl_sbd; struct buffer_head *bh; - if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) + if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) { + *bhp = NULL; return -EIO; + } *bhp = bh = gfs2_getbuf(gl, blkno, CREATE); @@ -235,6 +237,7 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags, if (tr && tr->tr_touched) gfs2_io_error_bh(sdp, bh); brelse(bh); + *bhp = NULL; return -EIO; } -- 1.7.4