Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 17 May 2019 14:37:46 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Dmitry Vyukov <dvyukov@gmail.com>
Cc:     catalin.marinas@arm.com, Dmitry Vyukov <dvyukov@google.com>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kmemleak: fix check for softirq context
Message-Id: <20190517143746.2157a759f65b4cbc73321124@linux-foundation.org>
In-Reply-To: <20190517171507.96046-1-dvyukov@gmail.com>
References: <20190517171507.96046-1-dvyukov@gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, 17 May 2019 19:15:07 +0200 Dmitry Vyukov <dvyukov@gmail.com> wrote:

> From: Dmitry Vyukov <dvyukov@google.com>
> 
> in_softirq() is a wrong predicate to check if we are in a softirq context.
> It also returns true if we have BH disabled, so objects are falsely
> stamped with "softirq" comm. The correct predicate is in_serving_softirq().
>
> ...
> 
> --- a/mm/kmemleak.c
> +++ b/mm/kmemleak.c
> @@ -588,7 +588,7 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
>  	if (in_irq()) {
>  		object->pid = 0;
>  		strncpy(object->comm, "hardirq", sizeof(object->comm));
> -	} else if (in_softirq()) {
> +	} else if (in_serving_softirq()) {
>  		object->pid = 0;
>  		strncpy(object->comm, "softirq", sizeof(object->comm));
>  	} else {

What are the user-visible runtime effects of this change?