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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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