io_uring: rw: Fix an unsigned comparison which can never be negative

[PATCH] io_uring: rw: Fix an unsigned comparison which can never be negative

Posted by Jiapeng Chong 3 years, 6 months ago

The parameter 'res' is defined as unsigned type, so the following if
statement is invalid, we can modify the type of res to long.
if (res < 0)
  	res = io->bytes_done;
else
  	res += io->bytes_done;

io_uring/rw.c:265 io_fixup_rw_res() warn: unsigned 'res' is never less than zero.

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=2184
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
---
 io_uring/rw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/io_uring/rw.c b/io_uring/rw.c
index b777c35378b9..08d88481153c 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -256,7 +256,7 @@ static bool __io_complete_rw_common(struct io_kiocb *req, long res)
 	return false;
 }
 
-static inline unsigned io_fixup_rw_res(struct io_kiocb *req, unsigned res)
+static inline unsigned io_fixup_rw_res(struct io_kiocb *req, long res)
 {
 	struct io_async_rw *io = req->async_data;
 
-- 
2.20.1.7.g153144c

Re: [PATCH] io_uring: rw: Fix an unsigned comparison which can never be negative

Posted by Jens Axboe 3 years, 6 months ago

On 9/14/22 11:49 PM, Jiapeng Chong wrote:
> The parameter 'res' is defined as unsigned type, so the following if
> statement is invalid, we can modify the type of res to long.
> if (res < 0)
>   	res = io->bytes_done;
> else
>   	res += io->bytes_done;
> 
> io_uring/rw.c:265 io_fixup_rw_res() warn: unsigned 'res' is never less than zero.

This one is already fixed here:

https://git.kernel.dk/cgit/linux-block/commit/?h=io_uring-6.0&id=62bb0647b14646fa6c9aa25ecdf67ad18f13523c

-- 
Jens Axboe