Re: [PATCH] umad.c: memset() ib_user_mad_reg_req structure to 0 before invoking ioctl()

[Hal Rosenstock <hal-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>]

On 7/4/2011 5:53 AM, sebastien dugue wrote:
> 
> This fixes the following warning issued by valgrind:
> 
> ==5287== Syscall param ioctl(generic) points to uninitialised byte(s)
> ==5287==    at 0x3C466D95D7: ioctl (in /lib64/libc-2.12.so)
> ==5287==    by 0x526C292: umad_register (umad.c:947)
> ==5287==    by 0x568D206: smp_engine_init (query_smp.c:228)
> ==5287==    by 0x5689F8F: ibnd_discover_fabric (ibnetdisc.c:537)
> ==5287==    by 0x411700: devmgr_discover_fabric (devmgr_discover.c:66)
> 
> Signed-off-by: Jean-Vincent Ficet <jean-vincent.ficet-6ktuUTfB/bM@public.gmane.org>
> 
> ---
> 
> diff --git a/src/umad.c b/src/umad.c
> index 45a9423..cac46a4 100644
> --- a/src/umad.c
> +++ b/src/umad.c
> @@ -892,6 +892,7 @@ int umad_register_oui(int fd, int mgmt_class, uint8_t rmpp_version,
>  		return -EINVAL;
>  	}
>  
> +	memset(&req, 0, sizeof(req));
>  	req.qpn = 1;
>  	req.mgmt_class = mgmt_class;
>  	req.mgmt_class_version = 1;
> @@ -928,6 +929,7 @@ int umad_register(int fd, int mgmt_class, int mgmt_version,
>  	    ("fd %d mgmt_class %u mgmt_version %u rmpp_version %d method_mask %p",
>  	     fd, mgmt_class, mgmt_version, rmpp_version, method_mask);
>  
> +	memset(&req, 0, sizeof(req));
>  	req.qpn = qp = (mgmt_class == 0x1 || mgmt_class == 0x81) ? 0 : 1;
>  	req.mgmt_class = mgmt_class;
>  	req.mgmt_class_version = mgmt_version;

I think this is a "false positive" in valgrind. memset of the request
isn't really needed for either of these APIs as all input fields are
filled in by the caller and the only one which isn't is id which is an
output field.

-- Hal
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