On Thu, Feb 07, 2019 at 04:33:23PM +1100, Andrew Donnellan wrote: > Some older gccs (<GCC 7), when invoked with -fsanitize-coverage=trace-pc, > cause a spurious uninitialised variable warning in dt_cpu_ftrs.c: > > arch/powerpc/kernel/dt_cpu_ftrs.c: In function > ‘cpufeatures_process_feature’: > arch/powerpc/kernel/dt_cpu_ftrs.c:686:7: warning: ‘m’ may be used > uninitialized in this function [-Wmaybe-uninitialized] > if (m->cpu_ftr_bit_mask)
It seems to me the warning is correct? If enable_unknown is false and no cpu_feature is found, it will in if (m->cpu_ftr_bit_mask) cur_cpu_spec->cpu_features |= m->cpu_ftr_bit_mask; enable random features (whatever was last in the table), or indeed access via NULL if the table is length 0? So maybe this should be if (known && m->cpu_ftr_bit_mask) cur_cpu_spec->cpu_features |= m->cpu_ftr_bit_mask; instead? (The code would be much clearer if all the known vs. !known codepath was fully separated here). Segher