From: Dave Jiang <[email protected]>

When the remote side is not up, we do not have all the context for the
transport, and that causes NULL ptr access. Have the debugfs reads check
to see if transport is up before we make access.

Signed-off-by: Dave Jiang <[email protected]>
---
 drivers/ntb/ntb_transport.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 30d8b52421ec..1764bb2fd265 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -438,13 +438,17 @@ static ssize_t debugfs_read(struct file *filp, char 
__user *ubuf, size_t count,
        char *buf;
        ssize_t ret, out_offset, out_count;
 
+       qp = filp->private_data;
+
+       if (!qp || !qp->link_is_up)
+               return 0;
+
        out_count = 1000;
 
        buf = kmalloc(out_count, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;
 
-       qp = filp->private_data;
        out_offset = 0;
        out_offset += snprintf(buf + out_offset, out_count - out_offset,
                               "NTB QP stats\n");
-- 
2.4.0.rc0.43.gcf8a8c6

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