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

[Philippe Mathieu-Daudé]

On 4/14/20 3:30 PM, Philippe Mathieu-Daudé wrote:
From: Mansour Ahmadi <mansour...@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 <mansour...@gmail.com>
Message-Id: <20200408003552.58095-1-mansour...@gmail.com>
[PMD: Add missing "qemu/error-report.h" include and TODO comment]
Signed-off-by: Philippe Mathieu-Daudé <phi...@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));
+        }
      }
  }