MOpt mode cause afl-fuzz to hang without fuzzing progress
apach301 opened this issue · comments
afl-fuzz secondary node (-S) hangs when MOpt mode is enabled (-L N; with N >= 0):
AFL++ v4.08c works well, the problem appears in v4.09c (by testing different commits between v4.08c and v4.09c I found that afl-fuzz started to hang in MOpt mode after a8185f8). If afl-fuzz launched with -M and -L it is not hanging.
introspection.txt contains only one line: CYCLE cycle=1 cycle_wo_finds=0 time_wo_finds=0 expand_havoc=0 queue=8.
The problem could be triggered by launching either instrumented fuzztarget or using QEMU mode.
do you mean that a8185f8 is the commit where MOpt starts to go wrong in -S mode? or the following commit is the culprit?
do you mean that a8185f8 is the commit where MOpt starts to go wrong in -S mode? or the following commit is the culprit?
I didn't figured out what exact changes affected -S mode, Only that a8185f8 (pendfav merge) is the first commit on dev-branch where I detected hanging (previous works normally in -S mode).
thanks for reporting.
I did a workaround for the bug, it is in the dev branch.
I will either remove Mopt or rewrite it in the future.