[PATCH 3.11 91/94] NTB: Add Error Handling in ntb_device_setup

[Greg Kroah-Hartman]

3.11-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jon Mason <jon.mason@xxxxxxxxx>

commit 3b12a0d15bd1559e72ad21d9d807fd2a6706f0ab upstream.

If an error is encountered in ntb_device_setup, it is possible that the
spci_cmd isn't populated.  Writes to the offset can result in a NULL
pointer dereference.  This issue is easily encountered by running in
NTB-RP mode, as it currently is not supported and will generate an
error.  To get around this issue, return if an error is encountered
prior to attempting to write to the spci_cmd offset.

Signed-off-by: Jon Mason <jon.mason@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/ntb/ntb_hw.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/ntb/ntb_hw.c
+++ b/drivers/ntb/ntb_hw.c
@@ -644,10 +644,13 @@ static int ntb_device_setup(struct ntb_d
 		rc = -ENODEV;
 	}
 
+	if (rc)
+		return rc;
+
 	/* Enable Bus Master and Memory Space on the secondary side */
 	writew(PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER, ndev->reg_ofs.spci_cmd);
 
-	return rc;
+	return 0;
 }
 
 static void ntb_device_free(struct ntb_device *ndev)


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