From: Brian Foster <bfoster@redhat.com>
To: Dave Chinner <david@fromorbit.com>
Cc: y@disappointment.disaster, xfs@oss.sgi.com
Subject: Re: [PATCH] xfs: only trace buffer items if they exist
Date: Mon, 9 Feb 2015 13:25:38 -0500 [thread overview]
Message-ID: <20150209182538.GG18336@laptop.bfoster> (raw)
In-Reply-To: <1423198008-30748-1-git-send-email-david@fromorbit.com>
On Fri, Feb 06, 2015 at 03:46:48PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> The commit 2d3d0c5 ("xfs: lobotomise xfs_trans_read_buf_map()") left
> a landmine in the tracing code: trace_xfs_trans_buf_read() is now
> call on all buffers that are read through this interface rather than
> just buffers in transactions. For buffers outside transaction
> context, bp->b_fspriv is null, and so the buf log item tracing
> functions cannot be called. This causes a NULL pointer dereference
> in the trace_xfs_trans_buf_read() function when tracing is turned
> on.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
Ah, I hit this a week or so ago and completely forgot to dig into it.
Thanks!
Reviewed-by: Brian Foster <bfoster@redhat.com>
> fs/xfs/xfs_trans_buf.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
> index 0a4d4ab..7579841 100644
> --- a/fs/xfs/xfs_trans_buf.c
> +++ b/fs/xfs/xfs_trans_buf.c
> @@ -327,9 +327,10 @@ xfs_trans_read_buf_map(
> return -EIO;
> }
>
> - if (tp)
> + if (tp) {
> _xfs_trans_bjoin(tp, bp, 1);
> - trace_xfs_trans_read_buf(bp->b_fspriv);
> + trace_xfs_trans_read_buf(bp->b_fspriv);
> + }
> *bpp = bp;
> return 0;
>
> --
> 2.0.0
>
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs
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prev parent reply other threads:[~2015-02-09 18:25 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-06 4:46 [PATCH] xfs: only trace buffer items if they exist Dave Chinner
2015-02-09 18:25 ` Brian Foster [this message]
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