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[PATCH 2/2] migration: Define BLK_MIG_BLOCK_SIZE as unsigned long long
From: |
Peter Maydell |
Subject: |
[PATCH 2/2] migration: Define BLK_MIG_BLOCK_SIZE as unsigned long long |
Date: |
Thu, 21 Jul 2022 12:52:07 +0100 |
When we use BLK_MIG_BLOCK_SIZE in expressions like
block_mig_state.submitted * BLK_MIG_BLOCK_SIZE, this multiplication
is done as 32 bits, because both operands are 32 bits. Coverity
complains about possible overflows because we then accumulate that
into a 64 bit variable.
Define BLK_MIG_BLOCK_SIZE as unsigned long long using the ULL suffix.
The only two current uses of it with this problem are both in
block_save_pending(), so we could just cast to uint64_t there, but
using the ULL suffix is simpler and ensures that we don't
accidentally introduce new variants of the same issue in future.
Resolves: Coverity CID 1487136, 1487175
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
I haven't tried to analyse the code to see if the multiplications
could ever actually end up overflowing, but I would assume
probably not.
migration/block.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/migration/block.c b/migration/block.c
index 9e5aae58982..3577c815a94 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -28,7 +28,7 @@
#include "sysemu/block-backend.h"
#include "trace.h"
-#define BLK_MIG_BLOCK_SIZE (1 << 20)
+#define BLK_MIG_BLOCK_SIZE (1ULL << 20)
#define BDRV_SECTORS_PER_DIRTY_CHUNK (BLK_MIG_BLOCK_SIZE >> BDRV_SECTOR_BITS)
#define BLK_MIG_FLAG_DEVICE_BLOCK 0x01
--
2.25.1