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Date: Tue, 20 Oct 2015 10:33:51 +0200
From: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20151020083351.GA6519@noname.redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v7 27/39] block: Add blk_remove_bs()
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To: Max Reitz <mreitz@redhat.com>
Cc: Alberto Garcia <berto@igalia.com>, qemu-block@nongnu.org, John Snow <jsnow@redhat.com>, qemu-devel@nongnu.org, Markus Armbruster <armbru@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>

Am 19.10.2015 um 17:53 hat Max Reitz geschrieben:
> This function removes the BlockDriverState associated with the given
> BlockBackend from that BB and sets the BDS pointer in the BB to NULL.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  block/block-backend.c          | 12 ++++++++++++
>  include/sysemu/block-backend.h |  1 +
>  2 files changed, 13 insertions(+)
> 
> diff --git a/block/block-backend.c b/block/block-backend.c
> index 19fdaae..eb7409c 100644
> --- a/block/block-backend.c
> +++ b/block/block-backend.c
> @@ -334,6 +334,18 @@ void blk_hide_on_behalf_of_hmp_drive_del(BlockBackend *blk)
>  }
>  
>  /*
> + * Disassociates the currently associated BlockDriverState from @blk.
> + */
> +void blk_remove_bs(BlockBackend *blk)
> +{
> +    blk_update_root_state(blk);
> +
> +    bdrv_unref(blk->bs);
> +    blk->bs->blk = NULL;

Use after free?

> +    blk->bs = NULL;
> +}

Kevin