# Basic info <!--- Add commit SHA used to reproduce --> Applies for current basop-main # Bug description Invalid array index in ACELP sanity check # Ways to reproduce 1) Build with clang sanitizer flags : CFLAGS += -fsanitize=address,undefined,nullability LDFLAGS += -fsanitize=address,undefined,nullability 2) Decode attached file: IVAS_dec -q -fr 20 -Tracefile stvOMASA_2ISM_2MASA2TC48c+10dB.wav_OMASA_2Dir2TC_2ISM_at_br_sw_techs_13_2_to_512_kbps_start_48_kbps_48kHz_in_48kHz_out_7_1_out_JBM_Prof_5.dectrace -VOIP 7_1 48 stvOMASA_2ISM_2MASA2TC48c+10dB.wav_OMASA_2Dir2TC_2ISM_at_br_sw_techs_13_2_to_512_kbps_start_48_kbps_48kHz_in_48kHz_out_7_1_out_JBM_Prof_5.netsimout out.wav 3) Output will show this message: ... lib_dec/dec_acelp_fx.c:174:9: runtime error: index -1 out of bounds for type 'const UWord32[9]' (aka 'const unsigned int[9]') SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior lib_dec/dec_acelp_fx.c:174:9 in ... 4) Proposed fix Move sanity check inside of an IF statement a few lines lower were the invalid memory access cannot happen, and the ELSE of that IF statement would have the same effect as if the sanity check triggers. <!--- Below are labels that will be added but are not shown in description. This is a template to help fill them. Add further information to the first row and remove and add labels as necessary. --> [stvOMASA_2ISM_2MASA2TC48c+10dB.wav_OMASA_2Dir2TC_2ISM_at_br_sw_techs_13_2_to_512_kbps_start_48_kbps_48kHz_in_48kHz_out_7_1_out_JBM_Prof_5.netsimout](/uploads/ddde633b7e7f0a040181e80e4833d038/stvOMASA_2ISM_2MASA2TC48c+10dB.wav_OMASA_2Dir2TC_2ISM_at_br_sw_techs_13_2_to_512_kbps_start_48_kbps_48kHz_in_48kHz_out_7_1_out_JBM_Prof_5.netsimout)