Issues with core pattern
You should follow the directions suggested by AFL.
afl-fuzz 2.52b by <email@example.com> [+] You have 2 CPU cores and 1 runnable tasks (utilization: 50%). [+] Try parallel jobs - see /usr/share/doc/afl-doc/docs/parallel_fuzzing.txt. [*] Checking CPU core loadout... [+] Found a free CPU core, binding to #0. [*] Checking core_pattern... [-] Hmm, your system is configured to send core dump notifications to an external utility. This will cause issues: there will be an extended delay between stumbling upon a crash and having this information relayed to the fuzzer via the standard waitpid() API. To avoid having crashes misinterpreted as timeouts, please log in as root and temporarily modify /proc/sys/kernel/core_pattern, like so: echo core >/proc/sys/kernel/core_pattern [-] PROGRAM ABORT : Pipe at the beginning of 'core_pattern' Location : check_crash_handling(), afl-fuzz.c:7275
No instrumentation detected
If AFL reports
No instrumentation detected, you must first set the environment variable:
afl-fuzz 2.52b by <firstname.lastname@example.org> [+] You have 2 CPU cores and 1 runnable tasks (utilization: 50%). [+] Try parallel jobs - see /usr/share/doc/afl-doc/docs/parallel_fuzzing.txt. [*] Checking CPU core loadout... [+] Found a free CPU core, binding to #0. [*] Checking core_pattern... [*] Setting up output directories... [*] Scanning 'seed_inputs'... [+] No auto-generated dictionary tokens to reuse. [*] Creating hard links for all input files... [*] Validating target binary... [-] Looks like the target binary is not instrumented! The fuzzer depends on compile-time instrumentation to isolate interesting test cases while mutating the input data. For more information, and for tips on how to instrument binaries, please see /usr/share/doc/afl-doc/docs/README. When source code is not available, you may be able to leverage QEMU mode support. Consult the README for tips on how to enable this. (It is also possible to use afl-fuzz as a traditional, "dumb" fuzzer. For that, you can use the -n option - but expect much worse results.) [-] PROGRAM ABORT : No instrumentation detected Location : check_binary(), afl-fuzz.c:6920
Issues with CPU frequency
You can set the following environment variable:
and/or follow the directions suggested by AFL.