From: Peter Zijlstra <peterz@infradead.org>
To: Pavel Machek <pavel@ucw.cz>
Cc: acme@redhat.com, kernel list <linux-kernel@vger.kernel.org>,
mingo@redhat.com, alexander.shishkin@linux.intel.com
Subject: Re: Getting interrupt every million cache misses
Date: Thu, 27 Oct 2016 11:15:43 +0200 [thread overview]
Message-ID: <20161027091543.GJ3102@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20161027084637.GA19469@amd>
On Thu, Oct 27, 2016 at 10:46:38AM +0200, Pavel Machek wrote:
> And actually, printk() is not needed, udelay(50msec) is. Reason is,
> that DRAM becomes unreliable if about milion cache misses happen in
> under 64msec -- so I'd like to slow the system down in such cases to
> prevent bug from biting me.
>
> (Details are here
> https://googleprojectzero.blogspot.cz/2015/03/exploiting-dram-rowhammer-bug-to-gain.html
> ). Bug is exploitable to get local root; it is also exploitable to
> gain local code execution from javascript... so it is rather severe.
Cute, a rowhammer defence.
So we can do in-kernel perf events too, see for example
kernel/watchdog.c:wd_hw_attr and its users.
I suppose you want PERF_COUNT_HW_CACHE_MISSES as config, although
depending on platform you could use better (u-arch specific) events.
next prev parent reply other threads:[~2016-10-27 9:16 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-26 20:54 Pavel Machek
2016-10-27 8:28 ` Peter Zijlstra
2016-10-27 8:46 ` Pavel Machek
2016-10-27 9:15 ` Peter Zijlstra [this message]
2016-10-27 9:11 ` Pavel Machek
2016-10-27 9:33 ` Peter Zijlstra
2016-10-27 20:40 ` Kees Cook
2016-10-27 21:27 ` rowhammer protection [was Re: Getting interrupt every million cache misses] Pavel Machek
2016-10-28 7:07 ` Ingo Molnar
2016-10-28 8:50 ` Pavel Machek
2016-10-28 8:59 ` Ingo Molnar
2016-10-28 11:55 ` Pavel Machek
2016-10-28 9:04 ` Peter Zijlstra
2016-10-28 9:27 ` Vegard Nossum
2016-10-28 9:35 ` Ingo Molnar
2016-10-28 9:47 ` Vegard Nossum
2016-10-28 9:53 ` [kernel-hardening] " Mark Rutland
2016-10-28 11:27 ` Pavel Machek
2016-10-28 9:51 ` [kernel-hardening] " Mark Rutland
2016-10-28 11:21 ` Pavel Machek
2016-10-28 14:05 ` Mark Rutland
2016-10-28 14:18 ` Peter Zijlstra
2016-10-28 18:30 ` Pavel Machek
2016-10-28 18:48 ` Peter Zijlstra
2016-11-02 18:13 ` Pavel Machek
2016-10-28 17:27 ` Pavel Machek
2016-10-29 13:06 ` Daniel Gruss
2016-10-29 19:42 ` Pavel Machek
2016-10-29 20:05 ` Daniel Gruss
2016-10-29 21:05 ` Pavel Machek
2016-10-29 21:07 ` Daniel Gruss
2016-10-29 21:45 ` Pavel Machek
2016-10-29 21:49 ` Daniel Gruss
2016-10-29 22:01 ` Pavel Machek
2016-10-29 22:02 ` Daniel Gruss
2016-10-31 8:27 ` Pavel Machek
2016-10-31 14:47 ` Mark Rutland
2016-10-31 21:13 ` Pavel Machek
2016-10-31 22:09 ` Mark Rutland
2016-11-01 6:33 ` Ingo Molnar
2016-11-01 7:20 ` Daniel Micay
2016-11-01 7:53 ` Daniel Gruss
2016-11-01 8:10 ` Pavel Machek
2016-11-01 8:13 ` Daniel Gruss
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