Clang build bot now uses two-stage builds, and other LLVM/LLDB news

Upstream describes LLDB as a next generation, high-performance debugger. It is built on top of LLVM/Clang toolchain, and features great integration with it. At the moment, it primarily supports debugging C, C++ and ObjC code, and there is interest in extending it to more languages.

In February, I have started working on LLDB, as contracted by the NetBSD Foundation. So far I've been working on reenabling continuous integration, squashing bugs, improving NetBSD core file support, extending NetBSD's ptrace interface to cover more register types and fix compat32 issues, and fixing watchpoint support. In October 2019, I've finished my work on threading support (pending pushes) and fought issues related to upgrade to NetBSD 9.

November was focused on finally pushing the aforementioned patches and major buildbot changes. Notably, I was working on extending the test runs to compiler-rt which required revisiting past driver issues, as well as resolving new ones. More details on this below.

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First release candidate for NetBSD 9.0 available!

Four months after the start of the release engineering process for 9.0, the first (and hopefully only) release candidate is now available.

The NetBSD 9.0 release comes with many new features and lots of improvements over the NetBSD 8.1 release...

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Debugging FFS Mount Failures

This report was written by Maciej Grochowski as a part of developing the AFL+KCOV project.

This report is a continuation of my previous work on Fuzzing Filesystems via AFL. You can find previous posts where I described the fuzzing (part1, part2) or my EuroBSDcon presentation.
In this part, we won't talk too much about fuzzing itself but I want to describe the process of finding root causes of File system issues and my recent work trying to improve this process.
This story begins with a mount issue that I found during my very first run of the AFL, and I presented it during my talk on EuroBSDcon in Lillehammer.

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Board of Directors and Officers elected

Per the membership voting, we have seated the new Board of Directors of the NetBSD Foundation:

• Taylor R. Campbell <riastadh@>
• William J. Coldwell <billc@>
• Michael van Elst <mlelstv@>
• Thomas Klausner <wiz@>
• Cherry G. Mathew <cherry@>
• Pierre Pronchery <khorben@>
• Leonardo Taccari <leot@>

We would like to thank Makoto Fujiwara <mef@> and Jeremy C. Reed <reed@> for their service on the Board of Directors during their term(s).

The new Board of Directors have voted in the executive officers for The NetBSD Foundation:

President:	William J. Coldwell
Vice President:	Pierre Pronchery
Secretary:	Christos Zoulas
Assistant Secretary:	Thomas Klausner
Treasurer:	Christos Zoulas
Assistant Treasurer:	Taylor R. Campbell

Thanks to everyone that voted and we look forward to a great 2020.

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LLDB Threading support now ready for mainline

Upstream describes LLDB as a next generation, high-performance debugger. It is built on top of LLVM/Clang toolchain, and features great integration with it. At the moment, it primarily supports debugging C, C++ and ObjC code, and there is interest in extending it to more languages.

In February, I have started working on LLDB, as contracted by the NetBSD Foundation. So far I've been working on reenabling continuous integration, squashing bugs, improving NetBSD core file support, extending NetBSD's ptrace interface to cover more register types and fix compat32 issues and fixing watchpoint support. Then, I've started working on improving thread support which is taking longer than expected. You can read more about that in my September 2019 report.

So far the number of issues uncovered while enabling proper threading support has stopped me from merging the work-in-progress patches. However, I've finally reached the point where I believe that the current work can be merged and the remaining problems can be resolved afterwards. More on that and other LLVM-related events happening during the last month in this report.

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Stabilization of the ptrace(2) threads continued

I have introduced changes to make debuggers more reliable in threaded scenarios. Additionally I have revamped micro-UBSan runtime for newer Clang (version 10git). I have received the OK from core@ to switch our iconv(3) to POSIX conformant iconv(3) and I have adapted where possible and readily known in pkgsrc to the newer API. This month I continued to find a solution to the impasse in LLD that blocks adding NetBSD support.[Read More] [0 comments]

 

Stabilization of the ptrace(2) threads

I have introduced changes that make debuggers more reliable in threaded scenarios. Additionally, I have enhanced Leak Sanitizer support and introduced various improvements in the basesystem.[Read More] [1 comment]

 

Threading support in LLDB continued

Upstream describes LLDB as a next generation, high-performance debugger. It is built on top of LLVM/Clang toolchain, and features great integration with it. At the moment, it primarily supports debugging C, C++ and ObjC code, and there is interest in extending it to more languages.

In February, I have started working on LLDB, as contracted by the NetBSD Foundation. So far I've been working on reenabling continuous integration, squashing bugs, improving NetBSD core file support, extending NetBSD's ptrace interface to cover more register types and fix compat32 issues and fixing watchpoint support. Then, I've started working on improving thread support. You can read more about that in my July 2019 report.

I've been on vacation in August, and in September I've resumed the work on LLDB. I've started by fixing new regressions in LLVM suite, then improved my previous patches and continued debugging test failures and timeouts resulting from my patches.

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EuroBSDCon 2019

Submitted by Maciej Grochowski.

This year This year EuroBSDCon took place in Lillehammer Norway. I had the pleasure to attend as a speaker with my talk about fuzzing the NetBSD filesystems.[Read More] [1 comment]

 

LLVM santizers and GDB regression test suite

As NetBSD-9 is branched, I have been asked to finish the LLVM sanitizer integration. This work is now accomplished and with MKLLVM=yes build option (by default off), the distribution will be populated with LLVM files for ASan, TSan, MSan, UBSan, libFuzzer, SafeStack and XRay.

I have also transplanted basesystem GDB patched to my GDB repository and managed to run the GDB regression test-suite.[Read More] [1 comment]

 

Enchancing Syzkaller Support for NetBSD, Part 3

Prepared by Siddharth Muralee(@R3x) as a part of Google Summer of Code’19

As a part of Google Summer of Code’19, I am working on improving the support for Syzkaller kernel fuzzer. Syzkaller is an unsupervised coverage-guided kernel fuzzer, that supports a variety of operating systems including NetBSD.

You can take a look through the first report to see the initial changes that we made and you can look at the second report to read about the initial support we added for fuzzing the network stack.

This report details the work done during the final coding period where the target was to improve the support for fuzzing the filesystem stack.

Filesystem fuzzing is a relatively less explored area. Syzkaller itself only has filesystem fuzzing support for Linux.

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Adapting TriforceAFL for NetBSD, Part 3

Prepared by Akul Pillai as part of GSoC 2019.

This is the third report summarising the work done in the third coding period for the GSoC project of Adapting TriforceAFL for NetBSD kernel syscall fuzzing.
Please also go through the first and second report.

This post also outlines the work done throughout the duration of GSoC, describes the implications of the same and future improvements to come.

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