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

[Joseph Qi]

On 8/15/22 4:57 PM, Heming Zhao wrote:
> 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>

Looks good.
Reviewed-by: Joseph Qi <joseph.qi at linux.alibaba.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);