From: f.fainelli@gmail.com (Florian Fainelli)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: mm: Facilitate debugging CONFIG_KUSER_HELPERS disabled
Date: Thu, 25 Oct 2018 11:50:43 -0700 [thread overview]
Message-ID: <a48601e2-dde2-47b8-b591-ffccdc9f1bf8@gmail.com> (raw)
In-Reply-To: <87tvl9nas6.fsf@xmission.com>
On 10/25/18 11:25 AM, Eric W. Biederman wrote:
> Florian Fainelli <f.fainelli@gmail.com> writes:
>
>> Some software such as perf makes unconditional use of the special
>> [vectors] page which is only provided when CONFIG_KUSER_HELPERS is
>> enabled in the kernel.
>>
>> Facilitate the debugging of such situations by printing a debug message
>> to the kernel log showing the task name and the faulting address.
>
> Can't someone trigger this segv deliberately and spam the kerne log?
> Doesn't this need something like printk_ratelimit or something to ensure
> this message only gets printed once?
Yes, good point, thanks.
--
Florian
WARNING: multiple messages have this Message-ID (diff)
From: Florian Fainelli <f.fainelli@gmail.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-arm-kernel@lists.infradead.org, andrew@lunn.ch,
Russell King <linux@armlinux.org.uk>,
Tony Lindgren <tony@atomide.com>,
Souptick Joarder <jrdr.linux@gmail.com>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ARM: mm: Facilitate debugging CONFIG_KUSER_HELPERS disabled
Date: Thu, 25 Oct 2018 11:50:43 -0700 [thread overview]
Message-ID: <a48601e2-dde2-47b8-b591-ffccdc9f1bf8@gmail.com> (raw)
In-Reply-To: <87tvl9nas6.fsf@xmission.com>
On 10/25/18 11:25 AM, Eric W. Biederman wrote:
> Florian Fainelli <f.fainelli@gmail.com> writes:
>
>> Some software such as perf makes unconditional use of the special
>> [vectors] page which is only provided when CONFIG_KUSER_HELPERS is
>> enabled in the kernel.
>>
>> Facilitate the debugging of such situations by printing a debug message
>> to the kernel log showing the task name and the faulting address.
>
> Can't someone trigger this segv deliberately and spam the kerne log?
> Doesn't this need something like printk_ratelimit or something to ensure
> this message only gets printed once?
Yes, good point, thanks.
--
Florian
next prev parent reply other threads:[~2018-10-25 18:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-25 18:09 [PATCH] ARM: mm: Facilitate debugging CONFIG_KUSER_HELPERS disabled Florian Fainelli
2018-10-25 18:09 ` Florian Fainelli
2018-10-25 18:25 ` Eric W. Biederman
2018-10-25 18:25 ` Eric W. Biederman
2018-10-25 18:50 ` Florian Fainelli [this message]
2018-10-25 18:50 ` Florian Fainelli
2018-10-25 18:30 ` Souptick Joarder
2018-10-25 18:30 ` Souptick Joarder
2018-10-25 18:48 ` Florian Fainelli
2018-10-25 18:48 ` Florian Fainelli
2018-10-25 19:06 ` Souptick Joarder
2018-10-25 19:06 ` Souptick Joarder
2018-10-25 21:20 ` Russell King - ARM Linux
2018-10-25 21:20 ` Russell King - ARM Linux
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