Re: [Qemu-devel] [PATCH] hw: intel_iommu: initialize 'name' in vtd_find_add_as

[Paolo Bonzini]

On 01/08/19 18:28, Li Qiang wrote:
> The 'name' variable in vtd_find_add_as function is not initialized
> now, so when in gdb, we will got following output:
> 
> (gdb) p name
> $1 = 
> "vtd-00.0\000\000\000\000\000\000\000\000\060\330\377\377\377\177\000\000\001\000\000\000\000\000\000\000p\330\377\377\377\177\000\000\353\362\372VUU\000\000p\330\377\377\377\177\000\000
>   
> \000\000\060b\000\000\220\021\000\000\360a\000\000\200\"\002\000\020a\000\000 
>  
> \000\000\060b\000\000\200\332\377\377\377\177\000\000\240\330\377\377\377\177\000\000<\364\372VUU\000\000\000\000\000\000\000\000\000\000
>   \000\000\060b\000"
> 
> After this patch, it is more clear:
> 
> (gdb) p name
> $1 = "vtd-00.0", '\000' <repeats 119 times>
> 
> Signed-off-by: Li Qiang <address@hidden>

There are hundreds of other occurrences of this same phenomenon.  It's
not a bug, it's just how the debugger chooses to print character arrays.

Paolo

> ---
>  hw/i386/intel_iommu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index de86f53b4e..e379c2a512 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -3286,7 +3286,7 @@ VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, 
> PCIBus *bus, int devfn)
>      uintptr_t key = (uintptr_t)bus;
>      VTDBus *vtd_bus = g_hash_table_lookup(s->vtd_as_by_busptr, &key);
>      VTDAddressSpace *vtd_dev_as;
> -    char name[128];
> +    char name[128] = {};
>  
>      if (!vtd_bus) {
>          uintptr_t *new_key = g_malloc(sizeof(*new_key));
>