[Fwd] Issue 25164 in oss-fuzz: qemu: Fuzzing build failure

[Alexander Bulekov]

Hi Paolo,
Our oss-fuzz builds started failing, after the meson merge. I think I
tracked down the issues:
1.) Looking at the build-log here:
https://oss-fuzz-build-logs.storage.googleapis.com/log-d43d402c-1ce5-4422-b3db-ccbf83a862a0.txt
The error happens at link-time. Re-running the build with V=1:
"/usr/bin/ld" ...
--whole-archive /usr/local/lib/clang/12.0.0/.../libclang_rt.asan-x86_64.a \
--start-group ..... -T /src/qemu/tests/qtest/fuzz/fork_fuzz.ld  \
-wrap qtest_inb -wrap qtest_inw ..... --end-group .....

I compared this against what we had before meson, and noticed that the
start-group/end-group are new. Removing those manually from the link
command, I can link successfully. It looks like these linker groups are
something that meson controls. Is there something we can tweak to make
the fork_fuzz.ld linker script apply to all the objects?

2.) 77afc75f69 ("oss-fuzz/build: remove LIB_FUZZING_ENGINE")

On oss-fuzz, we cannot explicitly specify fsanitize=fuzzer: We have to
leverage the $CC $CXX $CFLAGS $CXXFLAGS $LIB_FUZZING_ENGINE from
oss-fuzz. That was the reason for the "make CONFIG_FUZZ CFLAGS" trickery
in the original build script.

Details:
https://google.github.io/oss-fuzz/getting-started/new-project-guide/#Requirements

To work around this, I think we can create separate configure options
--enable-oss-fuzz and --oss-fuzz-cflags and CONFIG_OSS_FUZZ. In meson we
create a new "source-set" specific_oss_fuzz_ss which is identical to
specific_fuzz_ss, except it does not depend on "-fsanitize=fuzzer",
which is specified in tests/qtest/fuzz/meson.build

I've been working on patches to do (2) but I don't know how to fix (1).
Do you have any ideas?

-Alex

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Date: Sun, 23 Aug 2020 03:10:14 -0700
From: ClusterFuzz-External via monorail <monorail+v2.382749006@chromium.org>
To: alxndr@bu.edu
Subject: Issue 25164 in oss-fuzz: qemu: Fuzzing build failure

Status: New
Owner: ----
CC: b...@redhat.com, stefa...@redhat.com, alx...@bu.edu, pbonz...@redhat.com, 
darren.k...@oracle.com 
Labels: Proj-qemu
Type: Build-Failure

New issue 25164 by ClusterFuzz-External: qemu: Fuzzing build failure
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=25164

The last 2 builds for qemu have been failing.
Build log: 
https://oss-fuzz-build-logs.storage.googleapis.com/log-d43d402c-1ce5-4422-b3db-ccbf83a862a0.txt
Build type: fuzzing

To reproduce locally, please see: 
https://google.github.io/oss-fuzz/advanced-topics/reproducing#reproducing-build-failures

This bug tracker is not being monitored by OSS-Fuzz team. If you have any 
questions, please create an issue at 
https://github.com/google/oss-fuzz/issues/new.

**This bug will be automatically closed within a day once it is fixed.**

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