Re: [Xen-devel] [PATCH for-4.9 v3 2/3] xen/livepatch: Use zeroed memory allocations for arrays

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Thu, Jun 22, 2017 at 07:15:28PM +0100, Andrew Cooper wrote:
> Each of these arrays is sparse.  Use zeroed allocations to cause uninitialised
> array elements to contain deterministic values, most importantly for the
> embedded pointers.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
> CC: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>

Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
[x86 and ARM32]
> CC: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
> 
> * new in v3
> ---
>  xen/common/livepatch.c     | 4 ++--
>  xen/common/livepatch_elf.c | 4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/xen/common/livepatch.c b/xen/common/livepatch.c
> index df67a1a..66d532d 100644
> --- a/xen/common/livepatch.c
> +++ b/xen/common/livepatch.c
> @@ -771,8 +771,8 @@ static int build_symbol_table(struct payload *payload,
>          }
>      }
>  
> -    symtab = xmalloc_array(struct livepatch_symbol, nsyms);
> -    strtab = xmalloc_array(char, strtab_len);
> +    symtab = xzalloc_array(struct livepatch_symbol, nsyms);
> +    strtab = xzalloc_array(char, strtab_len);
>  
>      if ( !strtab || !symtab )
>      {
> diff --git a/xen/common/livepatch_elf.c b/xen/common/livepatch_elf.c
> index c4a9633..b69e271 100644
> --- a/xen/common/livepatch_elf.c
> +++ b/xen/common/livepatch_elf.c
> @@ -52,7 +52,7 @@ static int elf_resolve_sections(struct livepatch_elf *elf, 
> const void *data)
>      int rc;
>  
>      /* livepatch_elf_load sanity checked e_shnum. */
> -    sec = xmalloc_array(struct livepatch_elf_sec, elf->hdr->e_shnum);
> +    sec = xzalloc_array(struct livepatch_elf_sec, elf->hdr->e_shnum);
>      if ( !sec )
>      {
>          dprintk(XENLOG_ERR, LIVEPATCH"%s: Could not allocate memory for 
> section table!\n",
> @@ -225,7 +225,7 @@ static int elf_get_sym(struct livepatch_elf *elf, const 
> void *data)
>      /* No need to check values as elf_resolve_sections did it. */
>      nsym = symtab_sec->sec->sh_size / symtab_sec->sec->sh_entsize;
>  
> -    sym = xmalloc_array(struct livepatch_elf_sym, nsym);
> +    sym = xzalloc_array(struct livepatch_elf_sym, nsym);
>      if ( !sym )
>      {
>          dprintk(XENLOG_ERR, LIVEPATCH "%s: Could not allocate memory for 
> symbols\n",
> -- 
> 2.1.4
> 

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