[Ocfs2-devel] [PATCH v2] ocfs2: Fix freeing uninitialized resource on ocfs2_dlm_shutdown

[Heming Zhao]

After commit 0737e01de9c4 ("ocfs2: ocfs2_mount_volume does cleanup job
before return error"), any procedure after ocfs2_dlm_init() fails will
trigger crash when calling ocfs2_dlm_shutdown().

ie: On local mount mode, no dlm resource is initialized. If
ocfs2_mount_volume() fails in ocfs2_find_slot(), error handling
will call ocfs2_dlm_shutdown(), then does dlm resource cleanup
job, which will trigger kernel crash.

This solution should bypass uninitialized resources in
ocfs2_dlm_shutdown().

Fixes: 0737e01de9c4 ("ocfs2: ocfs2_mount_volume does cleanup job before return error")
Signed-off-by: Heming Zhao <heming.zhao at suse.com>
---
v1 -> v2:
 - by review comments:
   - revise commit log
   - remove improperly checking osb->cconn in ocfs2_dismount_volume()

draft -> v1:
 - separate to a single patch
 - by review comment:
   - do free lockres in shutdown path
   - put 'Fixes' string in one line
 - revise misspelled & grammar mistake in commit log
---
 fs/ocfs2/dlmglue.c | 8 +++++---
 fs/ocfs2/super.c   | 3 +--
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 801e60bab955..c28bc983a7b1 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -3403,10 +3403,12 @@ void ocfs2_dlm_shutdown(struct ocfs2_super *osb,
 	ocfs2_lock_res_free(&osb->osb_nfs_sync_lockres);
 	ocfs2_lock_res_free(&osb->osb_orphan_scan.os_lockres);
 
-	ocfs2_cluster_disconnect(osb->cconn, hangup_pending);
-	osb->cconn = NULL;
+	if (osb->cconn) {
+		ocfs2_cluster_disconnect(osb->cconn, hangup_pending);
+		osb->cconn = NULL;
 
-	ocfs2_dlm_shutdown_debug(osb);
+		ocfs2_dlm_shutdown_debug(osb);
+	}
 }
 
 static int ocfs2_drop_lock(struct ocfs2_super *osb,
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 438be028935d..bc18c27e9683 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -1914,8 +1914,7 @@ static void ocfs2_dismount_volume(struct super_block *sb, int mnt_err)
 	    !ocfs2_is_hard_readonly(osb))
 		hangup_needed = 1;
 
-	if (osb->cconn)
-		ocfs2_dlm_shutdown(osb, hangup_needed);
+	ocfs2_dlm_shutdown(osb, hangup_needed);
 
 	ocfs2_blockcheck_stats_debugfs_remove(&osb->osb_ecc_stats);
 	debugfs_remove_recursive(osb->osb_debug_root);
-- 
2.37.1