From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id 1B6997F50 for ; Thu, 19 Feb 2015 10:39:29 -0600 (CST) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay2.corp.sgi.com (Postfix) with ESMTP id 0A85B304043 for ; Thu, 19 Feb 2015 08:39:25 -0800 (PST) Received: from sandeen.net (sandeen.net [63.231.237.45]) by cuda.sgi.com with ESMTP id U1PEFOFGEswcpoED for ; Thu, 19 Feb 2015 08:39:23 -0800 (PST) Message-ID: <54E611BA.7010806@sandeen.net> Date: Thu, 19 Feb 2015 10:39:22 -0600 From: Eric Sandeen MIME-Version: 1.0 Subject: Re: [PATCH RFC] fs: xfs: Fix xfs_trans_read_buf event tracing References: <7fb3278485ca5d8b48cd1ba980be6cc11dafc11b.1424352124.git.panand@redhat.com> In-Reply-To: <7fb3278485ca5d8b48cd1ba980be6cc11dafc11b.1424352124.git.panand@redhat.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Pratyush Anand , david@fromorbit.com, xfs@oss.sgi.com Cc: jbastian@redhat.com, ddutile@redhat.com On 2/19/15 7:24 AM, Pratyush Anand wrote: > My root file system is xfs. As soon as I enable event for > xfs_trans_read_buf `echo xfs:xfs_trans_read_buf >> > /sys/kernel/debug/tracing/set_event`, I see a kernel panic. > > A little bit of debugging shows that bp->b_fspriv is NULL many a time > when trace_xfs_trans_read_buf(bp->b_fspriv) is called. > > I do not have any idea about xfs filesystem. So, I am not sure, if it > is expected to have bp->b_fspriv = NULL at this location. > > This patch fixes the issue, until we have a better fix. What kernel did you hit this on? What did the backtrace look like? I've been unable to reproduce the problem so far. Thanks, -Eric > Signed-off-by: Pratyush Anand > --- > fs/xfs/xfs_trans_buf.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c > index 0a4d4ab6d9a9..0b67a20643bf 100644 > --- a/fs/xfs/xfs_trans_buf.c > +++ b/fs/xfs/xfs_trans_buf.c > @@ -329,7 +329,8 @@ xfs_trans_read_buf_map( > > if (tp) > _xfs_trans_bjoin(tp, bp, 1); > - trace_xfs_trans_read_buf(bp->b_fspriv); > + if (bp->b_fspriv) > + trace_xfs_trans_read_buf(bp->b_fspriv); > *bpp = bp; > return 0; > > _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs