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[5/9] NTB: Fix oops in debugfs when transport is half-up

Message ID dc46fafa9893ffa92dad1a95fda17627dfff8c8a.1435587291.git.Allen.Hubbe@emc.com
State Not Applicable
Headers show

Commit Message

Allen Hubbe June 29, 2015, 2:50 p.m. UTC 
From: Dave Jiang <dave.jiang@intel.com>

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 <dave.jiang@intel.com>
---
 drivers/ntb/ntb_transport.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
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Patch

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");