From: Peter Chen <peter.chen@nxp.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Felipe Balbi <balbi@kernel.org>,
"pawell@cadence.com" <pawell@cadence.com>,
"rogerq@ti.com" <rogerq@ti.com>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
dl-linux-imx <linux-imx@nxp.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
Jun Li <jun.li@nxp.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: RE: [PATCH 1/3] usb: cdns3: gadget: suspicious implicit sign extension
Date: Wed, 28 Oct 2020 06:41:29 +0000 [thread overview]
Message-ID: <AM8PR04MB730012810E26CEE055A4E99C8B170@AM8PR04MB7300.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20201027142123.GA1233346@rowland.harvard.edu>
> That's a separate issue. I believe (but haven't checked) that the << operator
> has lower precedence than +, so the compiler interprets the expression as:
>
> unsigned int k = 0x80 << (24 + 0x81);
>
> and it's pretty obvious why this causes an error. Instead, try
> compiling:
>
> unsigned int k = (0x80 << 24) + 0x81;
>
> You may get an error message about signed-integer overflow, but not about
> shift-count overflow.
>
Hi Alan,
Your analysis is correct, I did not check the warning message correctly.
Peter
next prev parent reply other threads:[~2020-10-28 22:13 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-16 10:16 [PATCH 0/3] usb: cdns3: three bug fixes for v5.10 Peter Chen
2020-10-16 10:16 ` [PATCH 1/3] usb: cdns3: gadget: suspicious implicit sign extension Peter Chen
2020-10-27 9:03 ` Felipe Balbi
2020-10-27 9:48 ` Peter Chen
2020-10-27 10:08 ` David Laight
2020-10-27 14:21 ` Alan Stern
2020-10-28 6:41 ` Peter Chen [this message]
2020-10-27 9:03 ` Felipe Balbi
2020-10-16 10:16 ` [PATCH 2/3] usb: cdns3: gadget: own the lock wrongly at the suspend routine Peter Chen
2020-10-27 9:08 ` Felipe Balbi
2020-10-27 9:08 ` Felipe Balbi
2020-10-16 10:16 ` [PATCH 3/3] usb: cdns3: Fix on-chip memory overflow issue Peter Chen
2020-10-27 9:11 ` Felipe Balbi
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