scsi: target: Fix alua_tg_pt_gps_count tracking

BugLink: https://bugs.launchpad.net/bugs/1952579
[ Upstream commit 1283c0d1a32bb924324481586b5d6e8e76f676ba ]

We can't free the tg_pt_gp in core_alua_set_tg_pt_gp_id() because it's
still accessed via configfs. Its release must go through the normal
configfs/refcount process.

The max alua_tg_pt_gps_count check should probably have been done in
core_alua_allocate_tg_pt_gp(), but with the current code userspace could
have created 0x0000ffff + 1 groups, but only set the id for 0x0000ffff.
Then it could have deleted a group with an ID set, and then set the ID for
that extra group and it would work ok.

It's unlikely, but just in case this patch continues to allow that type of
behavior, and just fixes the kfree() while in use bug.

Link: https://lore.kernel.org/r/20210930020422.92578-4-michael.christie@oracle.com
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>

diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c
index cb1de1ecaaa61e2f552539e2f581f02b293a69ed..bd0f2ce011dd7fb27d622ef4b5276a30a464fb79 100644 (file)
--- a/drivers/target/target_core_alua.c
+++ b/drivers/target/target_core_alua.c
@@ -1674,7 +1674,6 @@ int core_alua_set_tg_pt_gp_id(
                pr_err("Maximum ALUA alua_tg_pt_gps_count:"
                        " 0x0000ffff reached\n");
                spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
-               kmem_cache_free(t10_alua_tg_pt_gp_cache, tg_pt_gp);
                return -ENOSPC;
        }
 again: