diff options
Diffstat (limited to 'instrumentation')
| -rw-r--r-- | instrumentation/README.llvm.md | 4 | ||||
| -rw-r--r-- | instrumentation/README.neverzero.md | 5 |
2 files changed, 9 insertions, 0 deletions
diff --git a/instrumentation/README.llvm.md b/instrumentation/README.llvm.md index adce6c1d..a9d51829 100644 --- a/instrumentation/README.llvm.md +++ b/instrumentation/README.llvm.md @@ -144,6 +144,10 @@ is not optimal and was only fixed in llvm 9. You can set this with AFL_LLVM_NOT_ZERO=1 See [README.neverzero.md](README.neverzero.md) +Support for thread safe counters has been added for mode LLVM CLASSIC. +Activate it with `AFL_LLVM_THREADSAFE_INST=1`. The tradeoff is better precision in +multi threaded apps for a slightly higher instrumentation overhead. + ## 4) Snapshot feature To speed up fuzzing you can use a linux loadable kernel module which enables diff --git a/instrumentation/README.neverzero.md b/instrumentation/README.neverzero.md index 49104e00..06334eab 100644 --- a/instrumentation/README.neverzero.md +++ b/instrumentation/README.neverzero.md @@ -33,3 +33,8 @@ AFL_LLVM_SKIP_NEVERZERO=1 ``` If the target does not have extensive loops or functions that are called a lot then this can give a small performance boost. + +Please note that the default counter implementations are not thread safe! + +Support for thread safe counters in mode LLVM CLASSIC can be activated with setting +`AFL_LLVM_THREADSAFE_INST=1`. \ No newline at end of file |