Re: [dm-devel] [PATCH] dm-mpath: Clear map_context pointer when requeuing

[Dave Wysochanski <dwysocha redhat com>]

On Wed, 2011-11-30 at 15:25 +0100, Hannes Reinecke wrote:
> When requeing a request we should be clearing the map_context
> pointer, otherwise we might access an invalid memory location.
> 
> Cc: Mike Snitzer <snitzer redhat com>
> Signed-off-by: Hannes Reinecke <hare suse de>
> Tested-by: Heiko Carstens <heiko carstens de ibm com>
> ---
>  drivers/md/dm-mpath.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
> index 5e0090e..e6fad46 100644
> --- a/drivers/md/dm-mpath.c
> +++ b/drivers/md/dm-mpath.c
> @@ -920,8 +920,10 @@ static int multipath_map(struct dm_target *ti, struct request *clone,
>  	map_context->ptr = mpio;
>  	clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
>  	r = map_io(m, clone, mpio, 0);
> -	if (r < 0 || r == DM_MAPIO_REQUEUE)
> +	if (r < 0 || r == DM_MAPIO_REQUEUE) {
>  		mempool_free(mpio, m->mpio_pool);
> +		map_context->ptr = NULL;
> +	}
>  
>  	return r;
>  }

Ack.