[SCSI] target: Fix top-level configfs_subsystem default_group shutdown breakage
This patch fixes two bugs uncovered during testing with
slub_debug=FPUZ during module_exit() -> target_core_exit_configfs()
with release of configfs subsystem consumer default groups, namely how
this should be working with
fs/configfs/dir.c:configfs_unregister_subsystem() release logic for
struct config_group->default_group.
The first issue involves configfs_unregister_subsystem() expecting to
walk+drain the top-level subsys->su_group.default_groups directly in
unlink_group(), and not directly from the configfs subsystem consumer
for the top level struct config_group->default_groups. This patch
drops the walk+drain of subsys->su_group.default_groups from TCM
configfs subsystem consumer code, and moves the top-level
->default_groups kfree() after configfs_unregister_subsystem() has
been called.
The second issue involves calling
core_alua_free_lu_gp(se_global->default_lu_gp) to release the
default_lu_gp->lu_gp_group before configfs_unregister_subsystem() has
been called. This patches also moves the core_alua_free_lu_gp() call
to release default_lu_group->lu_gp_group after the subsys has been
unregistered.
Finally, this patch explictly clears the
[lu_gp,alua,hba]_cg->default_groups pointers after kfree() to ensure
that no stale memory is picked up from child struct
config_group->default_group[] while configfs_unregister_subsystem() is
called.
Reported-by: Fubo Chen <fubo.chen@gmail.com>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 2764510..1cb74d5 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -3178,8 +3178,7 @@
config_item_put(item);
}
kfree(lu_gp_cg->default_groups);
- core_alua_free_lu_gp(se_global->default_lu_gp);
- se_global->default_lu_gp = NULL;
+ lu_gp_cg->default_groups = NULL;
alua_cg = &se_global->alua_group;
for (i = 0; alua_cg->default_groups[i]; i++) {
@@ -3188,6 +3187,7 @@
config_item_put(item);
}
kfree(alua_cg->default_groups);
+ alua_cg->default_groups = NULL;
hba_cg = &se_global->target_core_hbagroup;
for (i = 0; hba_cg->default_groups[i]; i++) {
@@ -3196,15 +3196,17 @@
config_item_put(item);
}
kfree(hba_cg->default_groups);
-
- for (i = 0; subsys->su_group.default_groups[i]; i++) {
- item = &subsys->su_group.default_groups[i]->cg_item;
- subsys->su_group.default_groups[i] = NULL;
- config_item_put(item);
- }
+ hba_cg->default_groups = NULL;
+ /*
+ * We expect subsys->su_group.default_groups to be released
+ * by configfs subsystem provider logic..
+ */
+ configfs_unregister_subsystem(subsys);
kfree(subsys->su_group.default_groups);
- configfs_unregister_subsystem(subsys);
+ core_alua_free_lu_gp(se_global->default_lu_gp);
+ se_global->default_lu_gp = NULL;
+
printk(KERN_INFO "TARGET_CORE[0]: Released ConfigFS Fabric"
" Infrastructure\n");