From e9892d3cc853afdda2cc69e2576d9ddb5fafad71 Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner@redhat.com>
Date: Tue, 10 Feb 2015 09:23:40 +1100
Subject: xfs: only trace buffer items if they exist
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.
cc: <stable@vger.kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
---
fs/xfs/xfs_trans_buf.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
(limited to 'fs/xfs/xfs_trans_buf.c')
diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
index 0a4d4ab6d9a9..75798412859a 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;
--
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