runtime/race: Race detector test fails on grsec kernels

[gopherbot]

by wizeman@wizy.org:

What steps will reproduce the problem?
1. Install Linux kernel patched with security enhancements from grsecurity.net
2. Run the race detector tests

What is the expected output?

Success

What do you see instead?

# Testing race detector.
==9105== ERROR: Failed to allocate 0x400000 (4194304) bytes at address 0x130800000000
(12)
==9105== ERROR: Failed to allocate 0x80000 (524288) bytes at address 0x600000000000 (12)
FATAL: ThreadSanitizer can not mmap thread trace
FAIL    flag    0.010s


Which version are you using?  (run 'go version')

1.1.2

Please provide any additional information below.

It seems to be a similar issue to the one fixed here:

https://golang.org/cl/5650072/

[dvyukov]

Comment 1:

We seem to be specifying MAP_FIXED when trying to allocate at particular address. Please
check with strace what exactly syscall fails.
Or do you want to say that we need to try to allocate w/o MAP_FIXED if MAP_FIXED fails?

Labels changed: added racedetector.

Owner changed to @dvyukov.

[gopherbot]

Comment 2 by wizeman@wizy.org:

Actually, it seems mmap() on those addresses fail with ENOMEM because grsec kernels with
UDEREF protection on amd64 reduce the available virtual address space to 42 bits (as
opposed to 47 bits on a default Linux kernel).
I suppose it's not easy to change (i.e configure or patch) the addresses which
ThreadSanitizer mmaps?
The code seems to come from LLVM, right?
BTW, how do I know which LLVM tag/commit does the ThreadSanitizer code distributed as a
binary blob in the source tarball come from? It doesn't seem to be documented in
go/src/pkg/runtime/race/README.

[dvyukov]

Comment 3:

LLVM rev on which the binary is built is present in latest src/pkg/runtime/race/README
files. Otherwise it must be noted in commit messages:
https://code.google.com/p/go/source/browse/src/pkg/runtime/race/README
Yes, the code comes from LLVM.
It's not that it's very difficult to changes the mappings, but it is somewhat tricky. We
have 4 different mappings:
http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/rtl/tsan_platform.h?view=markup
The mapping is fixed during build.
If you want to rebuild runtime, you need to run the following script:
http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/tsan/go/buildgo.sh?view=markup
it will give you race_linux_amd64.syso, which you can copy to Go tree.

[rsc]

Comment 4:

Labels changed: added go1.3maybe.

[dsymonds]

Comment 6:

Labels changed: removed priority-triage.

[rsc]

Comment 7:

Labels changed: added release-none, removed go1.3maybe.

[rsc]

Comment 8:

Labels changed: added repo-main.

[dvyukov]

Is there any interest in this issues? I am inclined to close as it is not particularly actionable.

[dvyukov]

non-actionable