From: "Luck, Tony" <tony.luck@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
"Yu, Fenghua" <fenghua.yu@intel.com>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
"Li, Xiaoyao" <xiaoyao.li@intel.com>,
"Shankar, Ravi V" <ravi.v.shankar@intel.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>,
"Yu, Fenghua" <fenghua.yu@intel.com>
Subject: RE: [PATCH v5 2/3] x86/bus_lock: Handle #DB for bus lock
Date: Fri, 19 Mar 2021 21:50:02 +0000 [thread overview]
Message-ID: <d98d86f9f5824573b2441089e0c2ae91@intel.com> (raw)
In-Reply-To: <871rca6dbp.fsf@nanos.tec.linutronix.de>
> What is the justifucation for making this rate limit per UID and not
> per task, per process or systemwide?
The concern is that a malicious user is running a workload that loops
obtaining the buslock. This brings the whole system to its knees.
Limiting per task doesn't help. The user can just fork(2) a whole bunch
of tasks for a distributed buslock attack..
Systemwide might be an interesting alternative. Downside would be accidental
rate limit of non-malicious tasks that happen to grab a bus lock periodically
but in the same window with other buslocks from other users.
Do you think that a risk worth taking to make the code simpler?
-Tony
next prev parent reply other threads:[~2021-03-19 21:51 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-13 5:49 [PATCH v5 0/3] x86/bus_lock: Enable bus lock detection Fenghua Yu
2021-03-13 5:49 ` [PATCH v5 1/3] x86/cpufeatures: Enumerate #DB for " Fenghua Yu
2021-03-19 20:35 ` Thomas Gleixner
2021-03-19 21:00 ` Fenghua Yu
2021-03-13 5:49 ` [PATCH v5 2/3] x86/bus_lock: Handle #DB for bus lock Fenghua Yu
2021-03-19 21:30 ` Thomas Gleixner
2021-03-19 21:50 ` Luck, Tony [this message]
2021-03-20 1:01 ` Thomas Gleixner
2021-03-20 13:57 ` Thomas Gleixner
2021-04-03 0:50 ` Fenghua Yu
2021-03-19 22:19 ` Fenghua Yu
2021-03-20 12:42 ` Thomas Gleixner
2021-04-03 1:04 ` Fenghua Yu
2021-04-12 7:15 ` Thomas Gleixner
2021-04-13 23:40 ` Fenghua Yu
2021-04-14 9:41 ` Thomas Gleixner
2021-03-13 5:49 ` [PATCH v5 3/3] Documentation/admin-guide: Change doc for split_lock_detect parameter Fenghua Yu
2021-03-19 21:35 ` Thomas Gleixner
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