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From: Tuguoyi <tu.guoyi@h3c.com>
To: Kevin Wolf <kwolf@redhat.com>, Max Reitz <mreitz@redhat.com>,
	"qemu-block@nongnu.org" <qemu-block@nongnu.org>
Cc: Chengchiwen <chengchiwen@h3c.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	Wangyong <wang.yongD@h3c.com>
Subject: [PATCH] block: Fix integer promotion error in bdrv_getlength()
Date: Thu, 5 Nov 2020 05:40:06 +0000	[thread overview]
Message-ID: <c0d398ea9d7141bcbb9b3746f97852b4@h3c.com> (raw)

As BDRV_SECTOR_SIZE is of type uint64_t, the expression will
automatically convert the @ret to uint64_t. When an error code
returned from bdrv_nb_sectors(), the promoted @ret will be a very
large number, as a result the -EFBIG will be returned which is not the
real error code.

Signed-off-by: Guoyi Tu <tu.guoyi@h3c.com>
---
 block.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block.c b/block.c
index 430edf7..f14254c 100644
--- a/block.c
+++ b/block.c
@@ -5082,7 +5082,7 @@ int64_t bdrv_getlength(BlockDriverState *bs)
 {
     int64_t ret = bdrv_nb_sectors(bs);
 
-    ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret;
+    ret = ret > INT64_MAX / (int64_t)BDRV_SECTOR_SIZE ? -EFBIG : ret;
     return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE;
 }
 
-- 
2.7.4

Please ignore the [PATCH] block: Return the real error code in bdrv_getlength

--
Best regards,
Guoyi

             reply	other threads:[~2020-11-05  5:41 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-05  5:40 Tuguoyi [this message]
2020-11-05  8:31 ` [PATCH] block: Fix integer promotion error in bdrv_getlength() Max Reitz
2020-11-05 13:14   ` Eric Blake
2020-11-05 13:26     ` Max Reitz
2020-11-05 15:39       ` Eric Blake
2020-11-06  2:06     ` Tuguoyi

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