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Message-ID: <alpine.LFD.2.21.1906302308280.3788@ja.home.ssi.bg>
Date: Sun, 30 Jun 2019 23:36:41 +0300 (EEST)
From: Julian Anastasov <ja@....bg>
To: Arnd Bergmann <arnd@...db.de>
cc: Kees Cook <keescook@...omium.org>,
Wensong Zhang <wensong@...ux-vs.org>,
Simon Horman <horms@...ge.net.au>,
"David S. Miller" <davem@...emloft.net>,
Alexey Kuznetsov <kuznet@....inr.ac.ru>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
Pablo Neira Ayuso <pablo@...filter.org>,
Jozsef Kadlecsik <kadlec@...filter.org>,
Florian Westphal <fw@...len.de>,
James Smart <james.smart@...adcom.com>,
Dick Kennedy <dick.kennedy@...adcom.com>,
"James E . J . Bottomley" <jejb@...ux.ibm.com>,
"Martin K . Petersen" <martin.petersen@...cle.com>,
Larry Finger <Larry.Finger@...inger.net>,
Florian Schilhabel <florian.c.schilhabel@...glemail.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
James Morris <jmorris@...ei.org>, linux-scsi@...r.kernel.org,
linux-kernel@...r.kernel.org, devel@...verdev.osuosl.org,
netdev@...r.kernel.org, lvs-devel@...r.kernel.org,
netfilter-devel@...r.kernel.org, coreteam@...filter.org,
Ard Biesheuvel <ard.biesheuvel@...aro.org>
Subject: Re: [PATCH 4/4] ipvs: reduce kernel stack usage
Hello,
On Fri, 28 Jun 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 %pIS 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.
>
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
> I'm not sure this actually does what I think it does. Someone
> needs to verify that we correctly print the addresses here.
> I've 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.
> ---
> include/net/ip_vs.h | 71 +++++++++++++++++++--------------
> net/netfilter/ipvs/ip_vs_core.c | 44 ++++++++++----------
> net/netfilter/ipvs/ip_vs_ftp.c | 20 +++++-----
> 3 files changed, 72 insertions(+), 63 deletions(-)
>
> diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
> index 3759167f91f5..3dfbeef67be6 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 +1255,31 @@ 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: "
> + "%pISp to %pISp\n",
ip_vs_dbg_addr() used compact form (%pI6c), so it would be
better to use %pISc and %pISpc everywhere in IPVS...
Also, note that before now port was printed with %d and
ntohs() was used, now port should be in network order, so:
- ntohs() should be removed
- htons() should be added, if missing. At first look, this case
is not present in IPVS, we have only ntohs() usage
Regards
--
Julian Anastasov <ja@....bg>
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