Congratulations to Hasan Hassan on his successful PhD defense

We’d like to congratulate our recent PhD graduate, Hasan Hassan, on his successful defense in September 2022!

Hasan Hassan, (defended 29 September 2022)
Thesis: “Improving DRAM Performance, Reliability, and Security by Rigorously Understanding Intrinsic DRAM Operation”
[Slides (pptx)(pdf)]
[Thesis arXiv (abs) (pdf)]
[Thesis Presentation Video]
[SAFARI Live Seminar Video]

Hasan started a new position with Rivos Inc. in October 2022.  We’d like to wish him all the best for a great start in his new position.

We interviewed Hasan after he won a Best Paper Award at IEEE S&P in 2020.  This interview originally appeared in our January 2021 Newsletter.  Here’s what he had to say:

You were a co-author on TRRespass, which recently won a Best Paper Award at IEEE S&P as well as a presigious Pwnie Award for Most Innovative Research. What is the significance of this paper?  

Hasan: Shortly after the discovery of the RowHammer vulnerability of DRAM, DRAM vendors announced RowHammer-free DRAM devices that implement in-DRAM solutions to protect against RowHammer. However, in TRRespass, we find that such solutions, commonly referred to as Target Row Refresh (TRR), do not effectively protect against RowHammer attacks when many rows are hammered at the same time. We show that the RowHammer vulnerability is not only still intact on the current DDR4 devices, but it has also become worse due to technology node scaling.

How was your experience in collaborating with the Systems and Network Security Group at VU Amsterdam on this work? 

Hasan: I am glad that our combined effort with the Systems and Network Security Group at VU Amsterdam won us the Best Paper Award at IEEE S&P. It has been a great experience for me to collaborate with experts in hardware security. I hope there will be more such collaborations that result in impactful research.

Which tools did you use in this work?

Hasan: I think SoftMC, our FPGA-based DRAM testing infrastructure, was one of the key enablers of this research. We used SoftMC to interface with DDR4 DRAM chips in a much more flexible way than anyone can do using commodity desktop and mobile systems. Specifically, we used SoftMC to communicate with DRAM chips using low-level DDR4 commands as opposed to using load/store instructions provided by typical instruction set architectures. In a way, SoftMC lets us be the memory controller and provides the flexibility of issuing any DDR4 command at any time, which is not possible with commodity systems.

An earlier version of SoftMC that supports DDR3 devices is open-source and can be accessed here. In 2017, we published a paper that describes the design of SoftMC in detail.

I am also involved in maintaining Ramulator, a cycle-accurate DRAM simulator that we describe in this paper, and Scarab, which is a cycle-accurate simulator for state-of-the-art multicore CPUs.

Pietro Frigo, Emanuele Vannacci, Hasan Hassan, Victor van der Veen, Onur Mutlu, Cristiano Giuffrida, Herbert Bos, and Kaveh Razavi
, TRRespass: Exploiting the Many Sides of Target Row Refresh, Proceedings of the 41st IEEE Symposium on Security and Privacy (S&P), San Francisco, CA, USA, May 2020.
Talk Video (17 minutes) | Lecture Video (59 minutes) | Lecture Slides (pptx)(pdf)
Source Code

Best paper award IEEE S&P
Pwnie Award 2020 for Most Innovative Research

Relevant PhD works:

Hasan Hassan, Ataberk Olgun, A. Giray Yaglikci, Haocong Luo, Onur Mutlu, “A Case for Self-Managing DRAM Chips: Improving Performance, Efficiency, Reliability, and Security via Autonomous in-DRAM Maintenance Operations”, Preprint on arXiv, July 2022.

Hasan Hassan, Yahya Can Tugrul, Jeremie S. Kim, Victor van der Veen, Kaveh Razavi, and Onur Mutlu“Uncovering In-DRAM RowHammer Protection Mechanisms: A New Methodology, Custom RowHammer Patterns, and Implications”Proceedings of the 54th International Symposium on Microarchitecture (MICRO), Virtual, October 2021.
[Slides (pptx) (pdf)]
[Short Talk Slides (pptx) (pdf)]
[Lightning Talk Slides (pptx) (pdf)]
[Talk Video (25 minutes)]
[Lightning Talk Video (100 seconds)]
[arXiv version]

Hasan Hassan, Minesh Patel, Jeremie S. Kim, A. Giray Yaglikci, Nandita Vijaykumar, Nika Mansourighiasi, Saugata Ghose, and Onur Mutlu“CROW: A Low-Cost Substrate for Improving DRAM Performance, Energy Efficiency, and Reliability”,  Proceedings of the 46th International Symposium on Computer Architecture (ISCA), Phoenix, AZ, USA, June 2019.
[Slides (pptx) (pdf)]
[Lightning Talk Slides (pptx) (pdf)]
[Poster (pptx) (pdf)]
[Lightning Talk Video (3 minutes)]
[Full Talk Video (16 minutes)]
[Full Talk Lecture (29 minutes)]
[Source Code for CROW (Ramulator and Circuit Modeling)]

Hasan Hassan, Nandita Vijaykumar, Samira Khan, Saugata Ghose, Kevin Chang, Gennady Pekhimenko, Donghyuk Lee, Oguz Ergin, and Onur Mutlu“SoftMC: A Flexible and Practical Open-Source Infrastructure for Enabling Experimental DRAM Studies” Proceedings of the 23rd International Symposium on High-Performance Computer Architecture (HPCA), Austin, TX, USA, February 2017.
[Slides (pptx) (pdf)] [Lightning Session Slides (pptx) (pdf)]
[Full Talk Lecture (39 minutes)]
[Source Code]



Posted in Papers, PhD Defense.