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KMSAN enables the use of LLVM's MemorySanitizer in the kernel. This enables precise detection of uses of uninitialized memory. As with KASAN, this feature has substantial runtime overhead and is intended to be used as part of some automated testing regime. The runtime maintains a pair of shadow maps. One is used to track the state of memory in the kernel map at bit-granularity: a bit in the kernel map is initialized when the corresponding shadow bit is clear, and is uninitialized otherwise. The second shadow map stores information about the origin of uninitialized regions of the kernel map, simplifying debugging. KMSAN relies on being able to intercept certain functions which cannot be instrumented by the compiler. KMSAN thus implements interceptors which manually update shadow state and in some cases explicitly check for uninitialized bytes. For instance, all calls to copyout() are subject to such checks. The runtime exports several functions which can be used to verify the shadow map for a given buffer. Helpers provide the same functionality for a few structures commonly used for I/O, such as CAM CCBs, BIOs and mbufs. These are handy when debugging a KMSAN report whose proximate and root causes are far away from each other. Obtained from: NetBSD Sponsored by: The FreeBSD Foundation
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|---|---|
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| cddl | Various commands and libraries under the Common Development and Distribution License. |
| contrib | Packages contributed by 3rd parties. |
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sys/arch/conf |
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