From: Nicholas Bellinger <n...@linux-iscsi.org>

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.

(Fix up context changes for v3.10.y - nab)

Reported-by: Chris Boot <c...@tiger-computing.co.uk>
Reported-by: Philip Gaw <p...@darktech.org.uk>
Cc: Chris Boot <c...@tiger-computing.co.uk>
Cc: Philip Gaw <p...@darktech.org.uk>
Signed-off-by: Nicholas Bellinger <n...@linux-iscsi.org>
---
 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 4a8bd36..8cda408 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -2034,6 +2034,11 @@ 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) {
-- 
1.8.5.3

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