From e9892d3cc853afdda2cc69e2576d9ddb5fafad71 Mon Sep 17 00:00:00 2001 From: Dave Chinner 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: Signed-off-by: Dave Chinner Reviewed-by: Brian Foster Signed-off-by: Dave Chinner --- 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; -- cgit v1.2.3-70-g09d2