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
