| Message ID | 20220331001717.616938-2-danielhb413@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ppc: valgrind "uninitialized values" fixes | expand |
On Wed, Mar 30, 2022 at 09:17:14PM -0300, Daniel Henrique Barboza wrote: > Valgrind isn't convinced that we are initializing the values we assign > to env->spr[spr] because it doesn't understand that the 'val' union is > being written by the kvm_vcpu_ioctl() that follows (via struct > kvm_one_reg). > > This results in Valgrind complaining about uninitialized values every > time we use env->spr in a conditional, like this instance: > > ==707578== Thread 1: > ==707578== Conditional jump or move depends on uninitialised value(s) > ==707578== at 0xA10A40: hreg_compute_hflags_value (helper_regs.c:106) > ==707578== by 0xA10C9F: hreg_compute_hflags (helper_regs.c:173) > ==707578== by 0xA110F7: hreg_store_msr (helper_regs.c:262) > ==707578== by 0xA051A3: ppc_cpu_reset (cpu_init.c:7168) > ==707578== by 0xD4730F: device_transitional_reset (qdev.c:799) > ==707578== by 0xD4A11B: resettable_phase_hold (resettable.c:182) > ==707578== by 0xD49A77: resettable_assert_reset (resettable.c:60) > ==707578== by 0xD4994B: resettable_reset (resettable.c:45) > ==707578== by 0xD458BB: device_cold_reset (qdev.c:296) > ==707578== by 0x48FBC7: cpu_reset (cpu-common.c:114) > ==707578== by 0x97B5EB: spapr_reset_vcpu (spapr_cpu_core.c:38) > ==707578== by 0x97BABB: spapr_cpu_core_reset (spapr_cpu_core.c:209) > ==707578== Uninitialised value was created by a stack allocation > ==707578== at 0xB11F08: kvm_get_one_spr (kvm.c:543) > > Initializing 'val' has no impact in the logic and makes Valgrind output > more bearable. > > Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > --- > target/ppc/kvm.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c > index dc93b99189..858866ecd4 100644 > --- a/target/ppc/kvm.c > +++ b/target/ppc/kvm.c > @@ -543,10 +543,11 @@ static void kvm_get_one_spr(CPUState *cs, uint64_t id, int spr) > { > PowerPCCPU *cpu = POWERPC_CPU(cs); > CPUPPCState *env = &cpu->env; > + /* Init 'val' to avoid "uninitialised value" Valgrind warnings */ > union { > uint32_t u32; > uint64_t u64; > - } val; > + } val = { }; > struct kvm_one_reg reg = { > .id = id, > .addr = (uintptr_t) &val,
diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c index dc93b99189..858866ecd4 100644 --- a/target/ppc/kvm.c +++ b/target/ppc/kvm.c @@ -543,10 +543,11 @@ static void kvm_get_one_spr(CPUState *cs, uint64_t id, int spr) { PowerPCCPU *cpu = POWERPC_CPU(cs); CPUPPCState *env = &cpu->env; + /* Init 'val' to avoid "uninitialised value" Valgrind warnings */ union { uint32_t u32; uint64_t u64; - } val; + } val = { }; struct kvm_one_reg reg = { .id = id, .addr = (uintptr_t) &val,