Commit e9892d3c authored Feb 10, 2015 by Dave Chinner Committed by Dave Chinner Feb 10, 2015

xfs: only trace buffer items if they exist



The commit 2d3d0c53 ("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>

parent 01f9882e

fs/xfs/xfs_trans_buf.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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);
		}
		*bpp = bp;
		return 0;