Re: [PATCH 08/16] ipvs: fix ip_vs_set_timeout debug messages

[Julian Anastasov <ja@ssi.bg>]

	Hello,

On Sat, 6 Oct 2012, Arnd Bergmann wrote:

> On Friday 05 October 2012, Julian Anastasov wrote:
> > 
> > 	Hello,
> > 
> > On Fri, 5 Oct 2012, Arnd Bergmann wrote:
> > 
> > > The ip_vs_set_timeout function sets timeouts for TCP and UDP, which
> > > can be enabled independently at compile time. The debug message
> > > always prints both timeouts that are passed into the function,
> > > but if one is disabled, the message will show uninitialized data.
> > > 
> > > This splits the debug message into two separte IP_VS_DBG statements
> > > that are in the same #ifdef section to ensure we only print the
> > > text about what is actually going on.
> > > 
> > > Without this patch, building ARM ixp4xx_defconfig results in:
> > 
> > 	Are there any CONFIG_IP_VS_PROTO_xxx options in this
> > default config? It is a waste of memory if IPVS is compiled
> > without any protocols.
> 
> They all appear to be turned off:
> 
> $ grep CONFIG_IP_VS obj-tmp/.config
> CONFIG_IP_VS=m
> CONFIG_IP_VS_DEBUG=y
> CONFIG_IP_VS_TAB_BITS=12
> # CONFIG_IP_VS_PROTO_TCP is not set
> # CONFIG_IP_VS_PROTO_UDP is not set
> # CONFIG_IP_VS_PROTO_AH_ESP is not set
> # CONFIG_IP_VS_PROTO_ESP is not set
> # CONFIG_IP_VS_PROTO_AH is not set
> # CONFIG_IP_VS_PROTO_SCTP is not set
> CONFIG_IP_VS_RR=m
> CONFIG_IP_VS_WRR=m
> CONFIG_IP_VS_LC=m
> CONFIG_IP_VS_WLC=m
> CONFIG_IP_VS_LBLC=m
> CONFIG_IP_VS_LBLCR=m
> CONFIG_IP_VS_DH=m
> CONFIG_IP_VS_SH=m
> # CONFIG_IP_VS_SED is not set
> # CONFIG_IP_VS_NQ is not set
> CONFIG_IP_VS_SH_TAB_BITS=8

	Something should be changed here, may be at least
TCP/UDP, who knows.

> > > net/netfilter/ipvs/ip_vs_ctl.c: In function 'ip_vs_genl_set_cmd':
> > > net/netfilter/ipvs/ip_vs_ctl.c:2238:47: warning: 't.udp_timeout' may be used uninitialized in this function [-Wuninitialized]
> > > net/netfilter/ipvs/ip_vs_ctl.c:3322:28: note: 't.udp_timeout' was declared here
> > > net/netfilter/ipvs/ip_vs_ctl.c:2238:47: warning: 't.tcp_fin_timeout' may be used uninitialized in this function [-Wuninitialized]
> > > net/netfilter/ipvs/ip_vs_ctl.c:3322:28: note: 't.tcp_fin_timeout' was declared here
> > > net/netfilter/ipvs/ip_vs_ctl.c:2238:47: warning: 't.tcp_timeout' may be used uninitialized in this function [-Wuninitialized]
> > > net/netfilter/ipvs/ip_vs_ctl.c:3322:28: note: 't.tcp_timeout' was declared here
> > 
> > 	There are many __ip_vs_get_timeouts callers but
> > just one calls memset(&t, 0, sizeof(t)) before that,
> > problem only for ip_vs_genl_set_config and ip_vs_set_timeout.
> > 
> > 	To be safe, can we move this memset into
> > __ip_vs_get_timeouts instead of playing games with defines?:
> > 
> > 	memset(t, 0, sizeof(*t));
> > 
> > 	This debug message will be more precise in showing the
> > changed values if we replace the __ip_vs_get_timeouts 
> > call in ip_vs_genl_set_config with memset(&t, 0, sizeof(t)).
> > Then we will see 0 for values that are not changed/supported.
> 
> 8<-----
> ipvs: initialize returned data in do_ip_vs_get_ctl
> 
> As reported by a gcc warning, the do_ip_vs_get_ctl does not initalize
> all the members of the ip_vs_timeout_user structure it returns if
> at least one of the TCP or UDP protocols is disabled for ipvs. 
> 
> This makes sure that the data is always initialized, before it is
> returned as a response to IPVS_CMD_GET_CONFIG or printed as a
> debug message in IPVS_CMD_SET_CONFIG.
> 
> Without this patch, building ARM ixp4xx_defconfig results in:
> 
> net/netfilter/ipvs/ip_vs_ctl.c: In function 'ip_vs_genl_set_cmd':
> net/netfilter/ipvs/ip_vs_ctl.c:2238:47: warning: 't.udp_timeout' may be used uninitialized in this function [-Wuninitialized]
> net/netfilter/ipvs/ip_vs_ctl.c:3322:28: note: 't.udp_timeout' was declared here
> net/netfilter/ipvs/ip_vs_ctl.c:2238:47: warning: 't.tcp_fin_timeout' may be used uninitialized in this function [-Wuninitialized]
> net/netfilter/ipvs/ip_vs_ctl.c:3322:28: note: 't.tcp_fin_timeout' was declared here
> net/netfilter/ipvs/ip_vs_ctl.c:2238:47: warning: 't.tcp_timeout' may be used uninitialized in this function [-Wuninitialized]
> net/netfilter/ipvs/ip_vs_ctl.c:3322:28: note: 't.tcp_timeout' was declared here
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> 
> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> index 2770f85..3995d2e 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c
> @@ -2590,6 +2588,7 @@ __ip_vs_get_timeouts(struct net *net, struct ip_vs_timeout_user *u)
>  #if defined(CONFIG_IP_VS_PROTO_TCP) || defined(CONFIG_IP_VS_PROTO_UDP)
>  	struct ip_vs_proto_data *pd;
>  #endif

	That is what we want. If you plan another submission
you can add empty line before this memset and to replace
the __ip_vs_get_timeouts call in ip_vs_genl_set_config with
memset but they are cosmetic changes. Or may be Simon will
take care about the coding style when applying the change.

Acked-by: Julian Anastasov <ja@ssi.bg>

> +	memset(u, 0, sizeof (*u));
>  
>  #ifdef CONFIG_IP_VS_PROTO_TCP
>  	pd = ip_vs_proto_data_get(net, IPPROTO_TCP);
> @@ -2768,7 +2767,6 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
>  	{
>  		struct ip_vs_timeout_user t;
>  
> -		memset(&t, 0, sizeof(t));
>  		__ip_vs_get_timeouts(net, &t);
>  		if (copy_to_user(user, &t, sizeof(t)) != 0)
>  			ret = -EFAULT;

Regards

--
Julian Anastasov <ja@ssi.bg>