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"Random" Segmentation Fault‚Äč

Running CI Fuzz with LLVM versions <=16 on Linux can cause Fuzzing runs to randomly crash with the following error message:

<fuzz_test_name>: signal: segmentation fault (core dumped)

This could be caused by the default ASLR (Address Space Layout Randomization) entropy value set by the OS. Sanitizers in earlier LLVM versions seem to have issues with a too high value (in this case 32).

To resolve this, you can either upgrade to a LLVM version >= 17 or you can set the entropy value to 28 or 30 with the following commands:

sudo cat /proc/sys/vm/mmap_rnd_bits
sudo sysctl vm.mmap_rnd_bits=28

Be aware that this value could be reset during OS updates.