[3.11.y.z extended stable] Patch "target: Fix alua_access_state attribute OOPs for un-configured devices" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    target: Fix alua_access_state attribute OOPs for un-configured devices

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From c94d049c764e3bc6e3c44076b8226140a4272667 Mon Sep 17 00:00:00 2001
From: Nicholas Bellinger <nab at linux-iscsi.org>
Date: Fri, 6 Jun 2014 00:52:57 -0700
Subject: target: Fix alua_access_state attribute OOPs for un-configured
 devices

commit f1453773514bb8b0bba0716301e8c8f17f8d39c7 upstream.

This patch fixes a OOPs where an attempt to write to the per-device
alua_access_state configfs attribute at:

  /sys/kernel/config/target/core/$HBA/$DEV/alua/$TG_PT_GP/alua_access_state

results in an NULL pointer dereference when the backend device has not
yet been configured.

This patch adds an explicit check for DF_CONFIGURED, and fails with
-ENODEV to avoid this case.

Reported-by: Chris Boot <crb at tiger-computing.co.uk>
Reported-by: Philip Gaw <pgaw at darktech.org.uk>
Cc: Chris Boot <crb at tiger-computing.co.uk>
Cc: Philip Gaw <pgaw at darktech.org.uk>
Signed-off-by: Nicholas Bellinger <nab at linux-iscsi.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/target/target_core_configfs.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index e4d22933efaf..304811e09649 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -2031,6 +2031,11 @@ static ssize_t target_core_alua_tg_pt_gp_store_attr_alua_access_state(
 			" tg_pt_gp ID: %hu\n", tg_pt_gp->tg_pt_gp_valid_id);
 		return -EINVAL;
 	}
+	if (!(dev->dev_flags & DF_CONFIGURED)) {
+		pr_err("Unable to set alua_access_state while device is"
+		       " not configured\n");
+		return -ENODEV;
+	}

 	ret = strict_strtoul(page, 0, &tmp);
 	if (ret < 0) {
--
1.9.1