Re: [Qemu-devel] [PATCH v2] ide: ahci: reset ncq object to unused on error

[John Snow <jsnow@redhat.com>]

On 01/08/2016 02:48 PM, P J P wrote:
> From: Prasad J Pandit <pjp@fedoraproject.org>
> 
> When processing NCQ commands, ACHI device emulation prepares a
> NCQ transfer object; To which an aio control block(aiocb) object
> is assigned in 'execute_ncq_command'. In case, when the NCQ
> command is invalid, the 'aiocb' object is not assigned, and NCQ
> transfer object is left as 'used'. This leads to a use after
> free kind of error in 'bdrv_aio_cancel_async' via 'ahci_reset_port'.
> Reset NCQ transfer object to 'unused' to avoid it.
> 
> Reported-by: Qinghao Tang <luodalongde@gmail.com>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
> ---
>  hw/ide/ahci.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> Update as per review in
>   -> https://lists.gnu.org/archive/html/qemu-devel/2016-01/msg01175.html
> 
> diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
> index dd1912e..17f1cbd 100644
> --- a/hw/ide/ahci.c
> +++ b/hw/ide/ahci.c
> @@ -910,6 +910,7 @@ static void ncq_err(NCQTransferState *ncq_tfs)
>      ide_state->error = ABRT_ERR;
>      ide_state->status = READY_STAT | ERR_STAT;
>      ncq_tfs->drive->port_regs.scr_err |= (1 << ncq_tfs->tag);
> +    ncq_tfs->used = 0;
>  }
>  
>  static void ncq_finish(NCQTransferState *ncq_tfs)
> 

Reviewed-by: John Snow <jsnow@redhat.com>