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

[Kamal Mostafa]

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-3.13.y-queue branch of the 3.13.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-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.4.

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

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 3d679c3b4dbb69c727eacc6daa7131356c11ddd3 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: Kamal Mostafa <kamal 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 272755d..afcbb04 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -2040,6 +2040,11 @@ 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 = kstrtoul(page, 0, &tmp);
 	if (ret < 0) {
--
1.9.1