Existing DSU implementations vary widely in their treatment of update points.
extension of the Linux kernel that allows security patches to be applied to a running kernel without the need for reboots, avoiding downtimes and improving availability (a technique broadly referred to as dynamic software updating).
Patch a running linux kernel Ksplice is an extension of the Linux kernel that allows security patches to be applied to a running kernel without the need for reboots, avoiding downtimes and improving availability (a technique broadly referred to as dynamic software updating).
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In this post, co-authored with my Ph D student Luís Pina, I take a closer look at the challenge that DSU presents, showing that what Linux will support is still quite far from what we might hope for, but that ideas from the research community promise to get us closer to the ideal, both for operating systems and hopefully for many other applications as well. If in the updated program the entries of a hash table are extended with a timeout field, then a dynamic update needs to convert in-memory hashtable entries to now contain a timeout field; otherwise, when the updated code goes to access that field, it will behave unpredictably.
In some systems, such as Up Stare and Po LUS, an update can occur at any time during execution.
Ginseng's compiler will attempt to infer good locations for update points, but can also use programmer-specified update points.
Ksplice allows system administrators to apply patches to their operating system kernels without rebooting.
Unlike previous hot update systems, Ksplice operates at the object code layer, which allows Ksplice to transform many traditional source code patches into hot updates with little or no programmer involvement.