[2.2.5-only] Make 'rmmod zfs' work after zfs-2.2.4 (#16406)

db65272ae was added to zfs-2.2.4 to stub in the
VDEV_PROP_RAIDZ_EXPANDING enum without adding the RAIDz expansion
feature.  This was needed to provide the right enum count for when the
VDEV_PROP_SLOW_IO proprieties got added.  This had the unfortunate side
effect of breaking module removal though.

Specifically, with the VDEV_PROP_RAIDZ_EXPANDING stub added,
the module would correctly omit making kobjects for the RAIDz expansion
vdev property, but then would try to blindly remove its non-existent
kobjects during module unload.

This commit fixes the issue by checking for an uninitialized kobject.

Fixes: #16249
Signed-off-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ameer Hamza <ahamza@ixsystems.com>
Reviewed-by: Tino Reichardt <milky-zfs@mcmilk.de>

diff --git a/module/os/linux/zfs/zfs_sysfs.c b/module/os/linux/zfs/zfs_sysfs.c
index e2431fe8a803fbb6db668b0f2d6cdcbbcd970545..b8cc682ad555b2412c98375e4f04bd0b0ccc8cfd 100644 (file)
--- a/module/os/linux/zfs/zfs_sysfs.c
+++ b/module/os/linux/zfs/zfs_sysfs.c
@@ -110,8 +110,17 @@ zfs_kobj_fini(zfs_mod_kobj_t *zkobj)
        }
 
        /* kobject_put() will call zfs_kobj_release() to release memory */
-       kobject_del(&zkobj->zko_kobj);
-       kobject_put(&zkobj->zko_kobj);
+       /*
+        * Special case note:
+        *
+        * We have to check for 'zkobj->zko_kobj.name != NULL' as
+        * a workaround for #16249 which was added to zfs-2.2.4
+        * and fixed (with this change) in zfs-2.2.5.
+        */
+       if (zkobj->zko_kobj.name != NULL) {
+               kobject_del(&zkobj->zko_kobj);
+               kobject_put(&zkobj->zko_kobj);
+       }
 }
 
 static void