Re: [Qemu-devel] [PATCH 14/38] ivshmem: Fix harmless misuse of Error

[Marc-André Lureau]

On Mon, Feb 29, 2016 at 7:40 PM, Markus Armbruster <address@hidden> wrote:
> We reuse errp after passing it host_memory_backend_get_memory().  If
> both host_memory_backend_get_memory() and the reuse set an error, the
> reuse will fail the assertion in error_setv().  Fortunately,
> host_memory_backend_get_memory() can't fail.
>
> Pass it &error_abort to make our assumption explicit, and to get the
> assertion failure in the right place should it become invalid.
>
> Signed-off-by: Markus Armbruster <address@hidden>
> ---

Reviewed-by: Marc-André Lureau <address@hidden>



>  hw/misc/ivshmem.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
> index 2850e8a..eb53d9a 100644
> --- a/hw/misc/ivshmem.c
> +++ b/hw/misc/ivshmem.c
> @@ -841,7 +841,7 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error 
> **errp)
>              g_warning("size argument ignored with hostmem");
>          }
>
> -        mr = host_memory_backend_get_memory(s->hostmem, errp);
> +        mr = host_memory_backend_get_memory(s->hostmem, &error_abort);
>          s->ivshmem_size = memory_region_size(mr);
>      } else if (s->sizearg == NULL) {
>          s->ivshmem_size = 4 << 20; /* 4 MB default */
> @@ -906,7 +906,8 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error 
> **errp)
>
>          IVSHMEM_DPRINTF("using hostmem\n");
>
> -        mr = host_memory_backend_get_memory(MEMORY_BACKEND(s->hostmem), 
> errp);
> +        mr = host_memory_backend_get_memory(MEMORY_BACKEND(s->hostmem),
> +                                            &error_abort);
>          vmstate_register_ram(mr, DEVICE(s));
>          memory_region_add_subregion(&s->bar, 0, mr);
>          pci_register_bar(PCI_DEVICE(s), 2, attr, &s->bar);
> @@ -1131,7 +1132,7 @@ static void ivshmem_check_memdev_is_busy(Object *obj, 
> const char *name,
>  {
>      MemoryRegion *mr;
>
> -    mr = host_memory_backend_get_memory(MEMORY_BACKEND(val), errp);
> +    mr = host_memory_backend_get_memory(MEMORY_BACKEND(val), &error_abort);
>      if (memory_region_is_mapped(mr)) {
>          char *path = object_get_canonical_path_component(val);
>          error_setg(errp, "can't use already busy memdev: %s", path);
> --
> 2.4.3
>
>



-- 
Marc-André Lureau