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Re: [PATCH] Update 'make fuzz-all' docs to reflect modern clang

From
Andrzej Hunt <andrzej@ahunt.org>
Date
Mar 4, 2021, 15:26 UTC
Message-ID
<094d75bf-707a-5b0d-fead-5c9ad08e0a18@ahunt.org>
In-Reply-To
<YD1tJlY/mqZOmTNm@google.com>
On 01/03/2021 23:39, Josh Steadmon wrote:
> Thanks for taking a look at this! This looked correct to me, but when I
> tried to run the fuzzers I got an error about
> "-fsanitize-coverage=trace-pc-guard" not being supported any longer.

Oops, I realised I was accidentally using clang 7 (instead of 11) locally. I can reproduce the same error with my copy of clang-11. Thanks for catching this!

Show 6 quoted lines
> Looking at the LLVM 11.0.0 docs [1], I see that it recommends using
> "-fsanitize=fuzzer-no-link" instead (the "-no-link" is because we're
> also building executables that have their own main()).
> 
> So we'd also want to change CFLAGS to
> "-fsanitize=fuzzer-no-link,address".
I will fix this too!

I suspect that when I built without fuzzer-no-link, the fuzzer binaries included libFuzzer, but were missing whatever fuzzing-related instrumentation clang should have added. (Fortunately oss-fuzz seems to be adding this to the CFLAGS automatically [1].)

[1] https://oss-fuzz-build-logs.storage.googleapis.com/log-74f40f33-f384-475b-b141-0e44afb272f5.txt

Previous: Josh SteadmonNext: Andrzej Hunt via GitGitGadget
Message 3 of 10 in “Update 'make fuzz-all' docs to reflect modern clang”
  1. Update 'make fuzz-all' docs to reflect modern clangAndrzej Hunt via GitGitGadget, Feb 28, 2021
  2. Josh SteadmonMar 1, 2021
  3. Andrzej HuntMar 4, 2021
  4. Update 'make fuzz-all' docs to reflect modern clangAndrzej Hunt via GitGitGadget, Mar 4, 2021
  5. Junio C HamanoMar 4, 2021
  6. Andrzej HuntMar 8, 2021
  7. Junio C HamanoMar 8, 2021
  8. Josh SteadmonMar 10, 2021
  9. Makefile: update 'make fuzz-all' docs to reflect modern clangAndrzej Hunt via GitGitGadget, Mar 8, 2021
  10. Josh SteadmonMar 10, 2021

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