Kernel Concurrency Sanitizer Set For Linux 5.5 To Uncover Data Race Conditions
Written by Michael Larabel in Linux Security on 25 November 2019 at 01:03 PM EST. 3 Comments
LINUX SECURITY --
Adding to the list of changes on deck for the Linux 5.5 kernel is a new "sanitizer" for spotting data race conditions.

The Linux kernel already has an address sanitizer, undefined behavior sanitizer, and other helpers while the newest is the kernel concurrency sanitizer. Like many of the sanitizers for the kernel and within compilers, the work comes courtesy of Google engineers.

The Kernel Concurrency Sanitizer should be able to spot data races within the kernel in real-time when built with the "KCSAN" support enabled. Due to the run-time overhead, this functionality shouldn't be bundled for production kernels but more for just testing builds.

Here's how it works: "KCSAN uses the -fsanitize=thread build time instrumentation features of both GCC and Clang, which transforms all memory reads/writes into __tsan_*callbacks with addresses and access type flags passed in that KCSAN can process and turn into a global array of 'watchpoints' that denote ongoing accesses. If two CPUs happen upon each other via an unsafe (non-atomic) access then a warning is generated."

The Kernel Concurrency Sanitizer is still being improved upon and for working around false-positives, but the initial implementation is ready for Linux 5.5.
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Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter or contacted via MichaelLarabel.com.

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