Details
| Original language | English |
|---|---|
| Pages | 651-666 |
| Number of pages | 16 |
| Publication status | Published - 2020 |
Abstract
Live patching has become a common technique to keep long-running system services secure and up-to-date without causing downtimes during patch application. However, to safely apply a patch, existing live-update methods require the entire process to enter a state of quiescence, which can be highly disruptive for multi-threaded programs: Having to halt all threads (e.g., at a global barrier) for patching not only hampers quality of service, but can also be tremendously difficult to implement correctly without causing deadlocks or other synchronization issues. In this paper, we present WFPATCH, a wait-free approach to inject code changes into running multi-threaded programs. Instead of having to stop the world before applying a patch, WFPATCH can gradually apply it to each thread individually at a local point of quiescence, while all other threads can make uninterrupted progress. We have implemented WFPATCH as a kernel service and user-space library for Linux 5.1 and evaluated it with OpenLDAP, Apache, Memcached, Samba, Node.js, and MariaDB on Debian 10 (“buster”). In total, we successfully applied 33 different binary patches into running programs while they were actively servicing requests; 15 patches had a CVE number or were other critical updates. Applying a patch with WFPATCH did not lead to any noticeable increase in request latencies - even under high load - while applying the same patch after reaching global quiescence increases tail latencies by a factor of up to 41× for MariaDB.
ASJC Scopus subject areas
- Computer Science(all)
- Computer Networks and Communications
- Computer Science(all)
- Hardware and Architecture
- Computer Science(all)
- Information Systems
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2020. 651-666.
Research output: Contribution to conference › Paper › Research › peer review
}
TY - CONF
T1 - From Global to Local Quiescence - Wait-Free Code Patching of Multi-Threaded Processes.
AU - Rommel, Florian
AU - Dietrich, Christian
AU - Friesel, Daniel
AU - Köppen, Marcel
AU - Borchert, Christoph
AU - Müller, Michael
AU - Spinczyk, Olaf
AU - Lohmann, Daniel
N1 - Funding information: We thank our anonymous reviewers and our shepherd Andrew Baumann for their constructive feedback and the efforts they made to improve this paper. We also thank Lennart Glauer for his work on an early WFPATCH prototype. This work was supported by the German Research Council (DFG) under the grants LO 1719/3, LO 1719/4, SP 968/9-2.
PY - 2020
Y1 - 2020
N2 - Live patching has become a common technique to keep long-running system services secure and up-to-date without causing downtimes during patch application. However, to safely apply a patch, existing live-update methods require the entire process to enter a state of quiescence, which can be highly disruptive for multi-threaded programs: Having to halt all threads (e.g., at a global barrier) for patching not only hampers quality of service, but can also be tremendously difficult to implement correctly without causing deadlocks or other synchronization issues. In this paper, we present WFPATCH, a wait-free approach to inject code changes into running multi-threaded programs. Instead of having to stop the world before applying a patch, WFPATCH can gradually apply it to each thread individually at a local point of quiescence, while all other threads can make uninterrupted progress. We have implemented WFPATCH as a kernel service and user-space library for Linux 5.1 and evaluated it with OpenLDAP, Apache, Memcached, Samba, Node.js, and MariaDB on Debian 10 (“buster”). In total, we successfully applied 33 different binary patches into running programs while they were actively servicing requests; 15 patches had a CVE number or were other critical updates. Applying a patch with WFPATCH did not lead to any noticeable increase in request latencies - even under high load - while applying the same patch after reaching global quiescence increases tail latencies by a factor of up to 41× for MariaDB.
AB - Live patching has become a common technique to keep long-running system services secure and up-to-date without causing downtimes during patch application. However, to safely apply a patch, existing live-update methods require the entire process to enter a state of quiescence, which can be highly disruptive for multi-threaded programs: Having to halt all threads (e.g., at a global barrier) for patching not only hampers quality of service, but can also be tremendously difficult to implement correctly without causing deadlocks or other synchronization issues. In this paper, we present WFPATCH, a wait-free approach to inject code changes into running multi-threaded programs. Instead of having to stop the world before applying a patch, WFPATCH can gradually apply it to each thread individually at a local point of quiescence, while all other threads can make uninterrupted progress. We have implemented WFPATCH as a kernel service and user-space library for Linux 5.1 and evaluated it with OpenLDAP, Apache, Memcached, Samba, Node.js, and MariaDB on Debian 10 (“buster”). In total, we successfully applied 33 different binary patches into running programs while they were actively servicing requests; 15 patches had a CVE number or were other critical updates. Applying a patch with WFPATCH did not lead to any noticeable increase in request latencies - even under high load - while applying the same patch after reaching global quiescence increases tail latencies by a factor of up to 41× for MariaDB.
UR - http://www.scopus.com/inward/record.url?scp=85096787683&partnerID=8YFLogxK
UR - https://dblp.org/rec/conf/osdi/RommelDFKBMSL20
M3 - Paper
SP - 651
EP - 666
ER -