Re: [PATCH 1/4] softmmu/cpus: Free cpu->thread in cpu_remove_sync()

["Philippe Mathieu-Daudé" <philippe.mathieu.daude@gmail.com>]

On 26/1/22 15:29, Mark Kanda wrote:
> vCPU hotunplug related leak reported by Valgrind:
> 
> ==377357== 8 bytes in 1 blocks are definitely lost in loss record 1,029 of 8,471
> ==377357==    at 0x4C3ADBB: calloc (vg_replace_malloc.c:1117)
> ==377357==    by 0x65C14CD: g_malloc0 (in /usr/lib64/libglib-2.0.so.0.5600.4)
> ==377357==    by 0x8B5AC8: kvm_start_vcpu_thread (kvm-accel-ops.c:68)
> ==377357==    by 0x7817AF: qemu_init_vcpu (cpus.c:634)
> ==377357==    by 0x7185A3: x86_cpu_realizefn (cpu.c:6447)
> ==377357==    by 0x8E46B7: device_set_realized (qdev.c:531)
> ==377357==    by 0x8EE36F: property_set_bool (object.c:2268)
> ==377357==    by 0x8EC3C5: object_property_set (object.c:1403)
> ==377357==    by 0x8F075D: object_property_set_qobject (qom-qobject.c:28)
> ==377357==    by 0x8EC72C: object_property_set_bool (object.c:1472)
> ==377357==    by 0x8E3F7F: qdev_realize (qdev.c:333)
> ==377357==    by 0x43F3A2: qdev_device_add_from_qdict (qdev-monitor.c:711)
> 
> Signed-off-by: Mark Kanda <mark.kanda@oracle.com>
> ---
>   softmmu/cpus.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/softmmu/cpus.c b/softmmu/cpus.c
> index 23bca46b07..1d8380d4aa 100644
> --- a/softmmu/cpus.c
> +++ b/softmmu/cpus.c
> @@ -603,6 +603,7 @@ void cpu_remove_sync(CPUState *cpu)
>       qemu_mutex_unlock_iothread();
>       qemu_thread_join(cpu->thread);
>       qemu_mutex_lock_iothread();
> +    g_free(cpu->thread);

Shouldn't we free that in a dedicated AccelOpsClass::destroy_vcpu_thread
handler instead? (Similarly to free CPUState::halt_cond, next patch).

>   }