powerpc/powernv : Drop reference added by kset_find_obj()

BugLink: http://bugs.launchpad.net/bugs/1619552
In a situation, where Linux kernel gets notified about duplicate error log
from OPAL, it is been observed that kernel fails to remove sysfs entries
(/sys/firmware/opal/elog/0xXXXXXXXX) of such error logs. This is because,
we currently search the error log/dump kobject in the kset list via
'kset_find_obj()' routine. Which eventually increment the reference count
by one, once it founds the kobject.

So, unless we decrement the reference count by one after it found the kobject,
we would not be able to release the kobject properly later.

This patch adds the 'kobject_put()' which was missing earlier.

Signed-off-by: Mukesh Ojha <mukesh02@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Reviewed-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
(cherry picked from commit a9cbf0b2195b695cbeeeecaa4e2770948c212e9a)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

diff --git a/arch/powerpc/platforms/powernv/opal-dump.c b/arch/powerpc/platforms/powernv/opal-dump.c
index 2ee96431f7360e1d8d63ece45520416860c62428..4c827826c05eb13b09f4e0cd9f9c73d6967ec9a9 100644 (file)
--- a/arch/powerpc/platforms/powernv/opal-dump.c
+++ b/arch/powerpc/platforms/powernv/opal-dump.c
@@ -370,6 +370,7 @@ static irqreturn_t process_dump(int irq, void *data)
        uint32_t dump_id, dump_size, dump_type;
        struct dump_obj *dump;
        char name[22];
+       struct kobject *kobj;
 
        rc = dump_read_info(&dump_id, &dump_size, &dump_type);
        if (rc != OPAL_SUCCESS)
@@ -381,8 +382,12 @@ static irqreturn_t process_dump(int irq, void *data)
         * that gracefully and not create two conflicting
         * entries.
         */
-       if (kset_find_obj(dump_kset, name))
+       kobj = kset_find_obj(dump_kset, name);
+       if (kobj) {
+               /* Drop reference added by kset_find_obj() */
+               kobject_put(kobj);
                return 0;
+       }
 
        dump = create_dump_obj(dump_id, dump_size, dump_type);
        if (!dump)

diff --git a/arch/powerpc/platforms/powernv/opal-elog.c b/arch/powerpc/platforms/powernv/opal-elog.c
index 37f959bf392e72a8a4bc7dee92181846b1383458..f2344cbd2f464cb93a3afbcbf21dc8263069b555 100644 (file)
--- a/arch/powerpc/platforms/powernv/opal-elog.c
+++ b/arch/powerpc/platforms/powernv/opal-elog.c
@@ -247,6 +247,7 @@ static irqreturn_t elog_event(int irq, void *data)
        uint64_t elog_type;
        int rc;
        char name[2+16+1];
+       struct kobject *kobj;
 
        rc = opal_get_elog_size(&id, &size, &type);
        if (rc != OPAL_SUCCESS) {
@@ -269,8 +270,12 @@ static irqreturn_t elog_event(int irq, void *data)
         * that gracefully and not create two conflicting
         * entries.
         */
-       if (kset_find_obj(elog_kset, name))
+       kobj = kset_find_obj(elog_kset, name);
+       if (kobj) {
+               /* Drop reference added by kset_find_obj() */
+               kobject_put(kobj);
                return IRQ_HANDLED;
+       }
 
        create_elog_obj(log_id, elog_size, elog_type);