[$] Finding race conditions with KCSAN

Race conditions can be some of the trickiest bugs to find. The resultingproblems can be subtle, and reproducing the problem in order to track itdown can be difficult or impossible; often code inserted to narrow down arace condition will cause it to stop manifesting entirely. A tool that canfind race conditions automatically would thus be a valuable thing for thekernel community to have. In late September, Marco Elver announceda tool called KCSAN (the Kernel Concurrency Sanitizer) that doesexactly that - and which has already found a number of real problems.