On Thu, Aug 01, 2013 at 03:14:00PM +0200, Tomas Henzl wrote:
> From: Tomas Henzl <the...@redhat.com>
> 
> When the driver calls scsi_done and after that frees it's internal
> preallocated memory it can happen that a new job is enqueud before
> the memory is freed. The allocation fails and the message
> "cmd_alloc returned NULL" is shown.
> Patch below fixes it by moving cmd->scsi_done after cmd_free.
> 
> Signed-off-by: Tomas Henzl <the...@redhat.com>
> ---
>  drivers/scsi/hpsa.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
> index d7df01e..48fa81e 100644
> --- a/drivers/scsi/hpsa.c
> +++ b/drivers/scsi/hpsa.c
> @@ -1180,8 +1180,8 @@ static void complete_scsi_command(struct CommandList 
> *cp)
>       scsi_set_resid(cmd, ei->ResidualCnt);
>  
>       if (ei->CommandStatus == 0) {
> -             cmd->scsi_done(cmd);
>               cmd_free(h, cp);
> +             cmd->scsi_done(cmd);
>               return;
>       }
>  
> @@ -1353,8 +1353,8 @@ static void complete_scsi_command(struct CommandList 
> *cp)
>               dev_warn(&h->pdev->dev, "cp %p returned unknown status %x\n",
>                               cp, ei->CommandStatus);
>       }
> -     cmd->scsi_done(cmd);
>       cmd_free(h, cp);
> +     cmd->scsi_done(cmd);
>  }
>  
>  static void hpsa_pci_unmap(struct pci_dev *pdev,
> -- 
> 1.8.3.1

Oh, nice catch!!!  Those mysterious and seemingly never reproducible
legends of the "cmd_alloc returned NULL" message that would show up
*extremely* infrequently are finally explained!

Ack.

-- steve
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