linux-kernel - Re: [PATCH v4 06/10] thermal: rockchip: consistently use int for temperatures

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Message-ID: <20151203004903.GA9543@google.com>
Date:	Wed, 2 Dec 2015 16:49:03 -0800
From:	Brian Norris <computersforpeace@...il.com>
To:	Caesar Wang <wxt@...k-chips.com>
Cc:	Heiko Stuebner <heiko@...ech.de>,
	Eduardo Valentin <edubezval@...il.com>, lkp@...el.com,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-rockchip@...ts.infradead.org,
	Zhang Rui <rui.zhang@...el.com>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v4 06/10] thermal: rockchip: consistently use int for
 temperatures

Hi Caesar,

On Thu, Dec 03, 2015 at 08:42:38AM +0800, Caesar Wang wrote:
> ? 2015?12?03? 02:38, Brian Norris ??:
> 
> [.....]
> >  	if (thermal->tshut_temp > INT_MAX) {
> >      CID 1341498:  Integer handling issues  (CONSTANT_EXPRESSION_RESULT)
> >      "thermal->tshut_temp > 2147483647 /* (int)(~0U >> 1) */" is always false regardless of the values of its operands. This occurs as the logical operand of if.
> >
> >I don't think this condition is even useful any more, so maybe we should
> >just kill the 'if' block.
> 
> See the patch to fix
> it.----->(https://patchwork.kernel.org/patch/7720601/)
> <https://patchwork.kernel.org/patch/7720601/>

-	if (thermal->tshut_temp > INT_MAX) {
+	if (!(thermal->tshut_temp < INT_MAX)) {

Huh? That still doesn't make much sense. The condition is still
impossible, since thermal->tshut_temp is an int. You've just made it
slightly harder for static analyzers to notice the impossibility.

> This patch is merged into kernel 4.4-rc3.

No it isn't, and I'm glad. The patch is silly.

Brian
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