dm ioctl: fix hang in early create error condition

The dm_early_create() function (which deals with "dm-mod.create=" kernel
command line option) calls dm_hash_insert() who gets an extra reference
to the md object.

In case of failure, this reference wasn't being released, causing
dm_destroy() to hang, thus hanging the whole boot process.

Fix this by calling __hash_remove() in the error path.

Fixes: 6bbc923dfcf57d ("dm: add support to directly boot to a mapped device")
Cc: stable@vger.kernel.org
Signed-off-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index c740153..1e03bc8 100644 (file)
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -2069,7 +2069,7 @@ int __init dm_early_create(struct dm_ioctl *dmi,
        /* alloc table */
        r = dm_table_create(&t, get_mode(dmi), dmi->target_count, md);
        if (r)
-               goto err_destroy_dm;
+               goto err_hash_remove;
 
        /* add targets */
        for (i = 0; i < dmi->target_count; i++) {
@@ -2116,6 +2116,10 @@ int __init dm_early_create(struct dm_ioctl *dmi,
 
 err_destroy_table:
        dm_table_destroy(t);
+err_hash_remove:
+       (void) __hash_remove(__get_name_cell(dmi->name));
+       /* release reference from __get_name_cell */
+       dm_put(md);
 err_destroy_dm:
        dm_put(md);
        dm_destroy(md);