Re: [PATCH-for-5.0 10/12] hw/block/pflash: Check return value of blk_pwrite()

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 4/14/20 3:30 PM, Philippe Mathieu-Daudé wrote:
> From: Mansour Ahmadi <mansourweb@gmail.com>
> 
> When updating the PFLASH file contents, we should check for a
> possible failure of blk_pwrite(). Similar to commit 3a688294e.
> 

There is actually a Coverity report for this issue, CID 1357678 
(Unchecked return value) from 2016-07-15 06:28:48:

CID 1357678 (#2 of 2): Unchecked return value (CHECKED_RETURN). 
check_return: Calling blk_pwrite without checking return value (as is 
done elsewhere 52 out of 59 times).

So it seems fair to add:

Reported-by: Coverity (CID 1357678 CHECKED_RETURN)

> Signed-off-by: Mansour Ahmadi <mansourweb@gmail.com>
> Message-Id: <20200408003552.58095-1-mansourweb@gmail.com>
> [PMD: Add missing "qemu/error-report.h" include and TODO comment]
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>   hw/block/pflash_cfi01.c | 8 +++++++-
>   hw/block/pflash_cfi02.c | 8 +++++++-
>   2 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
> index 24f3bce7ef..be1954c5d8 100644
> --- a/hw/block/pflash_cfi01.c
> +++ b/hw/block/pflash_cfi01.c
> @@ -42,6 +42,7 @@
>   #include "hw/qdev-properties.h"
>   #include "sysemu/block-backend.h"
>   #include "qapi/error.h"
> +#include "qemu/error-report.h"
>   #include "qemu/timer.h"
>   #include "qemu/bitops.h"
>   #include "qemu/error-report.h"
> @@ -399,13 +400,18 @@ static void pflash_update(PFlashCFI01 *pfl, int offset,
>                             int size)
>   {
>       int offset_end;
> +    int ret;
>       if (pfl->blk) {
>           offset_end = offset + size;
>           /* widen to sector boundaries */
>           offset = QEMU_ALIGN_DOWN(offset, BDRV_SECTOR_SIZE);
>           offset_end = QEMU_ALIGN_UP(offset_end, BDRV_SECTOR_SIZE);
> -        blk_pwrite(pfl->blk, offset, pfl->storage + offset,
> +        ret = blk_pwrite(pfl->blk, offset, pfl->storage + offset,
>                      offset_end - offset, 0);
> +        if (ret < 0) {
> +            /* TODO set error bit in status */
> +            error_report("Could not update PFLASH: %s", strerror(-ret));
> +        }
>       }
>   }
>   
> diff --git a/hw/block/pflash_cfi02.c b/hw/block/pflash_cfi02.c
> index 12f18d401a..c6b6f2d082 100644
> --- a/hw/block/pflash_cfi02.c
> +++ b/hw/block/pflash_cfi02.c
> @@ -37,6 +37,7 @@
>   #include "hw/block/flash.h"
>   #include "hw/qdev-properties.h"
>   #include "qapi/error.h"
> +#include "qemu/error-report.h"
>   #include "qemu/bitmap.h"
>   #include "qemu/timer.h"
>   #include "sysemu/block-backend.h"
> @@ -393,13 +394,18 @@ static uint64_t pflash_read(void *opaque, hwaddr offset, unsigned int width)
>   static void pflash_update(PFlashCFI02 *pfl, int offset, int size)
>   {
>       int offset_end;
> +    int ret;
>       if (pfl->blk) {
>           offset_end = offset + size;
>           /* widen to sector boundaries */
>           offset = QEMU_ALIGN_DOWN(offset, BDRV_SECTOR_SIZE);
>           offset_end = QEMU_ALIGN_UP(offset_end, BDRV_SECTOR_SIZE);
> -        blk_pwrite(pfl->blk, offset, pfl->storage + offset,
> +        ret = blk_pwrite(pfl->blk, offset, pfl->storage + offset,
>                      offset_end - offset, 0);
> +        if (ret < 0) {
> +            /* TODO set error bit in status */
> +            error_report("Could not update PFLASH: %s", strerror(-ret));
> +        }
>       }
>   }
>   
>