Hi Amit, Thanks for reporting this an proposing a fix. My review comments below:
Amit Machhiwal <[email protected]> writes: > GCC 16 tightens diagnostics around const correctness and now correctly > rejects attempts to modify strings referenced through const-qualified > pointers. In kvm_ppc_register_host_cpu_type(), ppc_cpu_aliases[i].model > is defined as const char *, but the code was using strstr() on it and > then modifying the returned pointer in-place to strip > POWERPC_CPU_TYPE_SUFFIX. > > This results in a write through a pointer derived from const data, > triggering a build failure with GCC 16: > > error: assignment discards 'const' qualifier from pointer target type > [-Werror=discarded-qualifiers] > suffix = strstr(ppc_cpu_aliases[i].model, POWERPC_CPU_TYPE_SUFFIX); > ^ > This looks more like an aliasing issue for the pointer returned by g_strdup and it being used between const and non-const contexts. > Fix this by duplicating the model string into a mutable buffer using > g_strdup(), storing it in the alias table, and then performing the > suffix truncation on the mutable copy. > > This preserves the existing behavior while avoiding modification of > const data and ensures compatibility with newer compilers. I think the better approach would be to avoid modifying the value returned by g_strdup before its assigned to 'ppc_cpu_alias[i].model' struct member. > > No functional change intended. > > Signed-off-by: Amit Machhiwal <[email protected]> > --- > target/ppc/kvm.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c > index 25c28ad089c6..e71e5c0117da 100644 > --- a/target/ppc/kvm.c > +++ b/target/ppc/kvm.c > @@ -2654,10 +2654,12 @@ static int kvm_ppc_register_host_cpu_type(void) > dc = DEVICE_CLASS(ppc_cpu_get_family_class(pvr_pcc)); > for (i = 0; ppc_cpu_aliases[i].alias != NULL; i++) { > if (g_ascii_strcasecmp(ppc_cpu_aliases[i].alias, dc->desc) == 0) { > + char *model; > char *suffix; > > - ppc_cpu_aliases[i].model = g_strdup(object_class_get_name(oc)); > - suffix = strstr(ppc_cpu_aliases[i].model, > POWERPC_CPU_TYPE_SUFFIX); > + model = g_strdup(object_class_get_name(oc)); while we are at it lets also handle ENOMEM error and trickle it back to arch_kvm_init() > + ppc_cpu_aliases[i].model = model; > + suffix = strstr(model, POWERPC_CPU_TYPE_SUFFIX); > if (suffix) { > *suffix = 0; > } > > base-commit: ac0cc20ad2fe0b8df2e5d9458e90a095ac711ab1 > -- > 2.50.1 (Apple Git-155) > > I have done the above proposed changes in a separate patch which i will post in some time. -- Cheers ~ Vaibhav
