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CVS commit: src

Module Name:    src
Committed By:   maxv
Date:           Tue Nov  5 20:19:18 UTC 2019

Modified Files:
        src/sys/arch/amd64/amd64: machdep.c mptramp.S
        src/sys/arch/amd64/conf: GENERIC Makefile.amd64
        src/sys/arch/x86/x86: cpu.c
        src/sys/conf: files
        src/sys/kern: files.kern
        src/sys/lib/libkern: libkern.h
        src/sys/sys: atomic.h bus_proto.h cdefs.h systm.h
Added Files:
        src/sys/arch/amd64/include: csan.h
        src/sys/kern: subr_csan.c
        src/sys/sys: csan.h

Log Message:
Add Kernel Concurrency Sanitizer (kCSan) support. This sanitizer allows us
to detect race conditions at runtime. It is a variation of TSan that is
easy to implement and more suited to kernel internals, albeit theoretically
less precise than TSan's happens-before.

We do basically two things:

 - On every KCSAN_NACCESSES (=2000) memory accesses, we create a cell
   describing the access, and delay the calling CPU (10ms).

 - On all memory accesses, we verify if the memory we're reading/writing
   is referenced in a cell already.

The combination of the two means that, if for example cpu0 does a read that
is selected and cpu1 does a write at the same address, kCSan will fire,
because cpu1's write collides with cpu0's read cell.

The coverage of the instrumentation is the same as that of kASan. Also, the
code is organized in a way similar to kASan, so it is easy to add support
for more architectures than amd64. kCSan is compatible with KCOV.

Reviewed by Kamil.

To generate a diff of this commit:
cvs rdiff -u -r1.294 -r1.295 src/share/mk/
cvs rdiff -u -r1.337 -r1.338 src/sys/arch/amd64/amd64/machdep.c
cvs rdiff -u -r1.26 -r1.27 src/sys/arch/amd64/amd64/mptramp.S
cvs rdiff -u -r1.544 -r1.545 src/sys/arch/amd64/conf/GENERIC
cvs rdiff -u -r1.78 -r1.79 src/sys/arch/amd64/conf/Makefile.amd64
cvs rdiff -u -r0 -r1.1 src/sys/arch/amd64/include/csan.h
cvs rdiff -u -r1.173 -r1.174 src/sys/arch/x86/x86/cpu.c
cvs rdiff -u -r1.1240 -r1.1241 src/sys/conf/files
cvs rdiff -u -r1.35 -r1.36 src/sys/kern/files.kern
cvs rdiff -u -r0 -r1.1 src/sys/kern/subr_csan.c
cvs rdiff -u -r1.132 -r1.133 src/sys/lib/libkern/libkern.h
cvs rdiff -u -r1.15 -r1.16 src/sys/sys/atomic.h
cvs rdiff -u -r1.9 -r1.10 src/sys/sys/bus_proto.h
cvs rdiff -u -r1.147 -r1.148 src/sys/sys/cdefs.h
cvs rdiff -u -r0 -r1.1 src/sys/sys/csan.h
cvs rdiff -u -r1.287 -r1.288 src/sys/sys/systm.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

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