Re: [PATCH] [v2 net-next] ipvs: reduce kernel stack usage

From: Julian Anastasov
Date: Thu Jul 25 2019 - 11:01:32 EST

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Hello,

On Mon, 22 Jul 2019, Arnd Bergmann wrote:

> With the new CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL option, the stack
> usage in the ipvs debug output grows because each instance of
> IP_VS_DBG_BUF() now has its own buffer of 160 bytes that add up
> rather than reusing the stack slots:
>
> net/netfilter/ipvs/ip_vs_core.c: In function 'ip_vs_sched_persist':
> net/netfilter/ipvs/ip_vs_core.c:427:1: error: the frame size of 1052 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
> net/netfilter/ipvs/ip_vs_core.c: In function 'ip_vs_new_conn_out':
> net/netfilter/ipvs/ip_vs_core.c:1231:1: error: the frame size of 1048 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
> net/netfilter/ipvs/ip_vs_ftp.c: In function 'ip_vs_ftp_out':
> net/netfilter/ipvs/ip_vs_ftp.c:397:1: error: the frame size of 1104 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
> net/netfilter/ipvs/ip_vs_ftp.c: In function 'ip_vs_ftp_in':
> net/netfilter/ipvs/ip_vs_ftp.c:555:1: error: the frame size of 1200 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
>
> Since printk() already has a way to print IPv4/IPv6 addresses using
> the %pISc format string, use that instead, combined with a macro that
> creates a local sockaddr structure on the stack. These will still
> add up, but the stack frames are now under 200 bytes.
>
> So far I have also only added three files that caused the warning
> messages to be reported. There are still a lot of other instances of
> IP_VS_DBG_BUF() that could be converted the same way after the
> basic idea is confirmed.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> v2:
> - use compressed ipv6 format
> - fix port number endianess

Thanks! Some comments below...

> ---
> include/net/ip_vs.h | 59 ++++++++++++++++-----------------
> net/netfilter/ipvs/ip_vs_core.c | 44 ++++++++++++------------
> net/netfilter/ipvs/ip_vs_ftp.c | 20 +++++------
> 3 files changed, 60 insertions(+), 63 deletions(-)
>
> diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
> index 3759167f91f5..eace4374e69f 100644
> --- a/include/net/ip_vs.h
> +++ b/include/net/ip_vs.h
> @@ -227,6 +227,16 @@ static inline const char *ip_vs_dbg_addr(int af, char *buf, size_t buf_len,
> sizeof(ip_vs_dbg_buf), addr, \
> &ip_vs_dbg_idx)
>
> +#define IP_VS_DBG_SOCKADDR4(fam, addr, port) \
> + (struct sockaddr*)&(struct sockaddr_in) \
> + { .sin_family = (fam), .sin_addr = (addr)->in, .sin_port = (port) }
> +#define IP_VS_DBG_SOCKADDR6(fam, addr, port) \
> + (struct sockaddr*)&(struct sockaddr_in6) \
> + { .sin6_family = (fam), .sin6_addr = (addr)->in6, .sin6_port = (port) }
> +#define IP_VS_DBG_SOCKADDR(fam, addr, port) (fam == AF_INET ? \
> + IP_VS_DBG_SOCKADDR4(fam, addr, port) : \
> + IP_VS_DBG_SOCKADDR6(fam, addr, port))
> +
> #define IP_VS_DBG(level, msg, ...) \
> do { \
> if (level <= ip_vs_get_debug_level()) \
> @@ -251,6 +261,7 @@ static inline const char *ip_vs_dbg_addr(int af, char *buf, size_t buf_len,
> #else /* NO DEBUGGING at ALL */
> #define IP_VS_DBG_BUF(level, msg...) do {} while (0)
> #define IP_VS_ERR_BUF(msg...) do {} while (0)
> +#define IP_VS_DBG_SOCKADDR(fam, addr, port) NULL
> #define IP_VS_DBG(level, msg...) do {} while (0)
> #define IP_VS_DBG_RL(msg...) do {} while (0)
> #define IP_VS_DBG_PKT(level, af, pp, skb, ofs, msg) do {} while (0)
> @@ -1244,31 +1255,23 @@ static inline void ip_vs_control_del(struct ip_vs_conn *cp)
> {
> struct ip_vs_conn *ctl_cp = cp->control;
> if (!ctl_cp) {
> - IP_VS_ERR_BUF("request control DEL for uncontrolled: "
> - "%s:%d to %s:%d\n",
> - IP_VS_DBG_ADDR(cp->af, &cp->caddr),
> - ntohs(cp->cport),
> - IP_VS_DBG_ADDR(cp->af, &cp->vaddr),
> - ntohs(cp->vport));
> + pr_err("request control DEL for uncontrolled: "
> + "%pISpc to %pISpcn",

Backslash was lost

> + IP_VS_DBG_SOCKADDR(cp->af, &cp->caddr, cp->cport),
> + IP_VS_DBG_SOCKADDR(cp->af, &cp->vaddr, cp->vport));
>
> return;
> }
>
> - IP_VS_DBG_BUF(7, "DELeting control for: "
> - "cp.dst=%s:%d ctl_cp.dst=%s:%d\n",
> - IP_VS_DBG_ADDR(cp->af, &cp->caddr),
> - ntohs(cp->cport),
> - IP_VS_DBG_ADDR(cp->af, &ctl_cp->caddr),
> - ntohs(ctl_cp->cport));
> + IP_VS_DBG(7, "DELeting control for: cp.dst=%pISpc ctl_cp.dst=%pISpc\n",
> + IP_VS_DBG_SOCKADDR(cp->af, &cp->caddr, cp->cport),
> + IP_VS_DBG_SOCKADDR(cp->af, &ctl_cp->caddr, ctl_cp->cport));
>
> cp->control = NULL;
> if (atomic_read(&ctl_cp->n_control) == 0) {
> - IP_VS_ERR_BUF("BUG control DEL with n=0 : "
> - "%s:%d to %s:%d\n",
> - IP_VS_DBG_ADDR(cp->af, &cp->caddr),
> - ntohs(cp->cport),
> - IP_VS_DBG_ADDR(cp->af, &cp->vaddr),
> - ntohs(cp->vport));
> + pr_err("BUG control DEL with n=0 : %pISpc to %pISpc\n",

We can remove the space before colon

> + IP_VS_DBG_SOCKADDR(cp->af, &cp->caddr, cp->cport),
> + IP_VS_DBG_SOCKADDR(cp->af, &cp->vaddr, cp->vport));
>
> return;
> }
> @@ -1279,22 +1282,18 @@ static inline void
> ip_vs_control_add(struct ip_vs_conn *cp, struct ip_vs_conn *ctl_cp)
> {
> if (cp->control) {
> - IP_VS_ERR_BUF("request control ADD for already controlled: "
> - "%s:%d to %s:%d\n",
> - IP_VS_DBG_ADDR(cp->af, &cp->caddr),
> - ntohs(cp->cport),
> - IP_VS_DBG_ADDR(cp->af, &cp->vaddr),
> - ntohs(cp->vport));
> + pr_err("request control ADD for already controlled: "
> + "%pISpc to %pISpc\n",
> + IP_VS_DBG_SOCKADDR(cp->af, &cp->caddr, cp->cport),
> + IP_VS_DBG_SOCKADDR(cp->af, &cp->vaddr, cp->vport));
>
> ip_vs_control_del(cp);
> }
>
> - IP_VS_DBG_BUF(7, "ADDing control for: "
> - "cp.dst=%s:%d ctl_cp.dst=%s:%d\n",
> - IP_VS_DBG_ADDR(cp->af, &cp->caddr),
> - ntohs(cp->cport),
> - IP_VS_DBG_ADDR(cp->af, &ctl_cp->caddr),
> - ntohs(ctl_cp->cport));
> + IP_VS_DBG(7, "ADDing control for: "
> + "cp.dst=%pISpc ctl_cp.dst=%pISpc\n",

May be we can join above lines

> + IP_VS_DBG_SOCKADDR(cp->af, &cp->caddr, cp->cport),
> + IP_VS_DBG_SOCKADDR(cp->af, &ctl_cp->caddr, ctl_cp->cport));
>
> cp->control = ctl_cp;
> atomic_inc(&ctl_cp->n_control);
> diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
> index 46f06f92ab8f..06ab0bf9ae08 100644
> --- a/net/netfilter/ipvs/ip_vs_core.c
> +++ b/net/netfilter/ipvs/ip_vs_core.c
> @@ -52,7 +52,6 @@
> #include <net/ip_vs.h>
> #include <linux/indirect_call_wrapper.h>
>
> -
> EXPORT_SYMBOL(register_ip_vs_scheduler);
> EXPORT_SYMBOL(unregister_ip_vs_scheduler);
> EXPORT_SYMBOL(ip_vs_proto_name);
> @@ -295,11 +294,11 @@ ip_vs_sched_persist(struct ip_vs_service *svc,
> #endif
> snet.ip = src_addr->ip & svc->netmask;
>
> - IP_VS_DBG_BUF(6, "p-schedule: src %s:%u dest %s:%u "
> - "mnet %s\n",
> - IP_VS_DBG_ADDR(svc->af, src_addr), ntohs(src_port),
> - IP_VS_DBG_ADDR(svc->af, dst_addr), ntohs(dst_port),
> - IP_VS_DBG_ADDR(svc->af, &snet));
> + IP_VS_DBG(6, "p-schedule: src %pISpc dest %pISpc "
> + "mnet %pIS\n",

Join? mnet %pISc ?

> + IP_VS_DBG_SOCKADDR(svc->af, src_addr, src_port),
> + IP_VS_DBG_SOCKADDR(svc->af, dst_addr, dst_port),
> + IP_VS_DBG_SOCKADDR(svc->af, &snet, 0));
>
> /*
> * As far as we know, FTP is a very complicated network protocol, and
> @@ -567,12 +566,12 @@ ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff *skb,
> }
> }
>
> - IP_VS_DBG_BUF(6, "Schedule fwd:%c c:%s:%u v:%s:%u "
> - "d:%s:%u conn->flags:%X conn->refcnt:%d\n",
> + IP_VS_DBG(6, "Schedule fwd:%c c:%pISpc v:%pISpc "
> + "d:%pISp conn->flags:%X conn->refcnt:%d\n",

d:%pISpc

> ip_vs_fwd_tag(cp),
> - IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
> - IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
> - IP_VS_DBG_ADDR(cp->daf, &cp->daddr), ntohs(cp->dport),
> + IP_VS_DBG_SOCKADDR(cp->af, &cp->caddr, cp->cport),
> + IP_VS_DBG_SOCKADDR(cp->af, &cp->vaddr, cp->vport),
> + IP_VS_DBG_SOCKADDR(cp->daf, &cp->daddr, cp->dport),
> cp->flags, refcount_read(&cp->refcnt));
>
> ip_vs_conn_stats(cp, svc);
> @@ -886,8 +885,8 @@ static int handle_response_icmp(int af, struct sk_buff *skb,
> /* Ensure the checksum is correct */
> if (!skb_csum_unnecessary(skb) && ip_vs_checksum_complete(skb, ihl)) {
> /* Failed checksum! */
> - IP_VS_DBG_BUF(1, "Forward ICMP: failed checksum from %s!\n",
> - IP_VS_DBG_ADDR(af, snet));
> + IP_VS_DBG(1, "Forward ICMP: failed checksum from %pISc!\n",
> + IP_VS_DBG_SOCKADDR(af, snet, 0));
> goto out;
> }
>
> @@ -1220,13 +1219,13 @@ struct ip_vs_conn *ip_vs_new_conn_out(struct ip_vs_service *svc,
> ip_vs_conn_stats(cp, svc);
>
> /* return connection (will be used to handle outgoing packet) */
> - IP_VS_DBG_BUF(6, "New connection RS-initiated:%c c:%s:%u v:%s:%u "
> - "d:%s:%u conn->flags:%X conn->refcnt:%d\n",
> - ip_vs_fwd_tag(cp),
> - IP_VS_DBG_ADDR(cp->af, &cp->caddr), ntohs(cp->cport),
> - IP_VS_DBG_ADDR(cp->af, &cp->vaddr), ntohs(cp->vport),
> - IP_VS_DBG_ADDR(cp->af, &cp->daddr), ntohs(cp->dport),
> - cp->flags, refcount_read(&cp->refcnt));
> + IP_VS_DBG(6, "New connection RS-initiated:%c c:%pISpc v:%pISpc "
> + "d:%pISp conn->flags:%X conn->refcnt:%d\n",

d:%pISpc

> + ip_vs_fwd_tag(cp),
> + IP_VS_DBG_SOCKADDR(cp->af, &cp->caddr, cp->cport),
> + IP_VS_DBG_SOCKADDR(cp->af, &cp->vaddr, cp->vport),
> + IP_VS_DBG_SOCKADDR(cp->af, &cp->daddr, cp->dport),
> + cp->flags, refcount_read(&cp->refcnt));
> LeaveFunction(12);
> return cp;
> }
> @@ -1969,7 +1968,6 @@ static int ip_vs_in_icmp_v6(struct netns_ipvs *ipvs, struct sk_buff *skb,
> }
> #endif
>
> -
> /*
> * Check if it's for virtual services, look it up,
> * and send it on its way...
> @@ -1998,10 +1996,10 @@ ip_vs_in(struct netns_ipvs *ipvs, unsigned int hooknum, struct sk_buff *skb, int
> hooknum != NF_INET_LOCAL_OUT) ||
> !skb_dst(skb))) {
> ip_vs_fill_iph_skb(af, skb, false, &iph);
> - IP_VS_DBG_BUF(12, "packet type=%d proto=%d daddr=%s"
> + IP_VS_DBG(12, "packet type=%d proto=%d daddr=%pISc"
> " ignored in hook %u\n",
> skb->pkt_type, iph.protocol,
> - IP_VS_DBG_ADDR(af, &iph.daddr), hooknum);
> + IP_VS_DBG_SOCKADDR(af, &iph.daddr, 0), hooknum);
> return NF_ACCEPT;
> }
> /* ipvs enabled in this netns ? */
> diff --git a/net/netfilter/ipvs/ip_vs_ftp.c b/net/netfilter/ipvs/ip_vs_ftp.c
> index cf925906f59b..22099c42e184 100644
> --- a/net/netfilter/ipvs/ip_vs_ftp.c
> +++ b/net/netfilter/ipvs/ip_vs_ftp.c
> @@ -306,9 +306,9 @@ static int ip_vs_ftp_out(struct ip_vs_app *app, struct ip_vs_conn *cp,
> &start, &end) != 1)
> return 1;
>
> - IP_VS_DBG_BUF(7, "EPSV response (%s:%u) -> %s:%u detected\n",
> - IP_VS_DBG_ADDR(cp->af, &from), ntohs(port),
> - IP_VS_DBG_ADDR(cp->af, &cp->caddr), 0);
> + IP_VS_DBG(7, "EPSV response (%pISpc) -> %pISc detected\n",
> + IP_VS_DBG_SOCKADDR(cp->af, &from, port),
> + IP_VS_DBG_SOCKADDR(cp->af, &cp->caddr, 0));
> } else {
> return 1;
> }
> @@ -510,15 +510,15 @@ static int ip_vs_ftp_in(struct ip_vs_app *app, struct ip_vs_conn *cp,
> &to, &port, cp->af,
> &start, &end) == 1) {
>
> - IP_VS_DBG_BUF(7, "EPRT %s:%u detected\n",
> - IP_VS_DBG_ADDR(cp->af, &to), ntohs(port));
> + IP_VS_DBG(7, "EPRT %pISpc detected\n",
> + IP_VS_DBG_SOCKADDR(cp->af, &to, port));
>
> /* Now update or create a connection entry for it */
> - IP_VS_DBG_BUF(7, "protocol %s %s:%u %s:%u\n",
> - ip_vs_proto_name(ipvsh->protocol),
> - IP_VS_DBG_ADDR(cp->af, &to), ntohs(port),
> - IP_VS_DBG_ADDR(cp->af, &cp->vaddr),
> - ntohs(cp->vport)-1);
> + IP_VS_DBG(7, "protocol %s %pISpc %pISpc\n",
> + ip_vs_proto_name(ipvsh->protocol),
> + IP_VS_DBG_SOCKADDR(cp->af, &to, port),
> + IP_VS_DBG_SOCKADDR(cp->af, &cp->vaddr,
> + htons(ntohs(cp->vport)-1)));
> } else {
> return 1;
> }
> --
> 2.20.0

Regards

--
Julian Anastasov <ja@xxxxxx>

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