From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752067AbdBHViM (ORCPT ); Wed, 8 Feb 2017 16:38:12 -0500 Received: from mout.kundenserver.de ([212.227.17.13]:63773 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751837AbdBHViK (ORCPT ); Wed, 8 Feb 2017 16:38:10 -0500 From: Arnd Bergmann To: "David S. Miller" Cc: David Laight , netdev@vger.kernel.org, johannes.berg@intel.com, Arnd Bergmann , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , kasan-dev@googlegroups.com, Nicolas Dichtel , Alexey Dobriyan , Daniel Borkmann , Thomas Graf , Eric Dumazet , linux-kernel@vger.kernel.org Subject: [PATCH] netlink: move nla_put_{u8,u16,u32} out of line Date: Wed, 8 Feb 2017 22:18:26 +0100 Message-Id: <20170208211843.2822208-1-arnd@arndb.de> X-Mailer: git-send-email 2.9.0 X-Provags-ID: V03:K0:LpbxCpYrZHkw7AazeDLUJiR3nfssM3vWvDbEdZD3CTMffjg5Daq PAWPsELKOgRFkmLXtXkwXS5kp4j4KQ/x2iSAkdYB/xCZ4234E9FFxZAGJKIQjQraN4/EW3x fuUAyA9gOw7wXFf+JIgFKn4IJ6bWecr8/J2UFCKRCC83KjvX30OpowVLOhmw6H+1A72ofd1 ehwEO7T/Rpecb6HROOwoQ== X-UI-Out-Filterresults: notjunk:1;V01:K0:kGwI2+1s+84=:gXHLG5gWrikVvt8qa3RMel RuvpTwugbpShXdzMSCOO09GzqDMgTNI2dLFj/4eiyT4GBhN+Z5n2U4a/+W2P4h3SUggLM3+cA 72m8afXNCAS+fyYaZ3KJKgYcRks2QUb7qs7LoGj3NZzpUFPHvpeEUfMbt9pCASoTV/hivIxBR SpanZXuBsDPPlYiy6TbjJoFvOVPowGS5IoNdOhIoezjY8G1YCJlKixQEGgHfzcRW2C5UAzvpD fMhiWMMq5wpzIXuzmCN+JpEFVHgq+irs5G3QGHhuIzTBMMwFlL8J25Wgt1Zr34WZp5XyZzJ70 YwEFhOCZf+MPot9R4skkiVEGg/0c1bHk7Ogmvp8T6umGc4HABWo6ovDcygSs9qz6mPjwDK//s n49XIwr4mt+o4WtKEK+jWM+KUYtSJwGPJQEmT/jJIY2bDTo1Z4J4UdmN/Jnl1gDPUZXP7s7Dk 6uEa+C8yqLRlmYN9McyZq0F2WqGWZrWy5c/khdSsZ7oqtvQNRQmNEd5zG/eZv9nrSVy4D3bbs JxqK1hPDoeFJXRpGbH0Fwp5+hYX4BOfUZQEjokMJ010T6sjvU/ekz8lCcEz8OZd9sW3Gtsu2e Gis1lS7+aEScLAdbrcfwZZJtgJ4PTb1m+gukB99CTvOF3RwywabslOgleWaY8REqdI3KlVC2q fGpQb1vj/djd3zWkFSkHJduKriO0aQ8682k8e2/D/yahh7EV4k+oSvqnpDmh8PvYx0cs= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When CONFIG_KASAN is enabled, the "--param asan-stack=1" causes rather large stack frames in some functions. This goes unnoticed normally because CONFIG_FRAME_WARN is disabled with CONFIG_KASAN by default as of commit 3f181b4d8652 ("lib/Kconfig.debug: disable -Wframe-larger-than warnings with KASAN=y"). The kernelci.org build bot however has the warning enabled and that led me to investigate it a little further, as every build produces these warnings: net/wireless/nl80211.c:4389:1: warning: the frame size of 2240 bytes is larger than 2048 bytes [-Wframe-larger-than=] net/wireless/nl80211.c:1895:1: warning: the frame size of 3776 bytes is larger than 2048 bytes [-Wframe-larger-than=] net/wireless/nl80211.c:1410:1: warning: the frame size of 2208 bytes is larger than 2048 bytes [-Wframe-larger-than=] net/bridge/br_netlink.c:1282:1: warning: the frame size of 2544 bytes is larger than 2048 bytes [-Wframe-larger-than=] It turns out that there is a relatively simple workaround for the netlink users that currently use a local variable in order to do the type conversion: Moving the three functions (for each of the typical sizes) to lib/nlattr.c avoids using local variables in the caller, which drastically reduces the stack usage for nl80211 and br_netlink. It would be good if we could enable the frame size check after that again, but that should be a separate patch and it requires some more testing to see which the largest acceptable frame size should be. Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: kasan-dev@googlegroups.com Signed-off-by: Arnd Bergmann --- include/net/netlink.h | 23 +++++++---------------- lib/nlattr.c | 18 ++++++++++++++++++ 2 files changed, 25 insertions(+), 16 deletions(-) diff --git a/include/net/netlink.h b/include/net/netlink.h index b239fcd33d80..48b117e80509 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -755,10 +755,7 @@ static inline int nla_parse_nested(struct nlattr *tb[], int maxtype, * @attrtype: attribute type * @value: numeric value */ -static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value) -{ - return nla_put(skb, attrtype, sizeof(u8), &value); -} +extern int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value); /** * nla_put_u16 - Add a u16 netlink attribute to a socket buffer @@ -766,10 +763,7 @@ static inline int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value) * @attrtype: attribute type * @value: numeric value */ -static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value) -{ - return nla_put(skb, attrtype, sizeof(u16), &value); -} +extern int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value); /** * nla_put_be16 - Add a __be16 netlink attribute to a socket buffer @@ -779,7 +773,7 @@ static inline int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value) */ static inline int nla_put_be16(struct sk_buff *skb, int attrtype, __be16 value) { - return nla_put(skb, attrtype, sizeof(__be16), &value); + return nla_put_u16(skb, attrtype, (u16 __force)value); } /** @@ -801,7 +795,7 @@ static inline int nla_put_net16(struct sk_buff *skb, int attrtype, __be16 value) */ static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value) { - return nla_put(skb, attrtype, sizeof(__le16), &value); + return nla_put_u16(skb, attrtype, (u16 __force)value); } /** @@ -810,10 +804,7 @@ static inline int nla_put_le16(struct sk_buff *skb, int attrtype, __le16 value) * @attrtype: attribute type * @value: numeric value */ -static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value) -{ - return nla_put(skb, attrtype, sizeof(u32), &value); -} +int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value); /** * nla_put_be32 - Add a __be32 netlink attribute to a socket buffer @@ -823,7 +814,7 @@ static inline int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value) */ static inline int nla_put_be32(struct sk_buff *skb, int attrtype, __be32 value) { - return nla_put(skb, attrtype, sizeof(__be32), &value); + return nla_put_u32(skb, attrtype, (u32 __force)value); } /** @@ -845,7 +836,7 @@ static inline int nla_put_net32(struct sk_buff *skb, int attrtype, __be32 value) */ static inline int nla_put_le32(struct sk_buff *skb, int attrtype, __le32 value) { - return nla_put(skb, attrtype, sizeof(__le32), &value); + return nla_put_u32(skb, attrtype, (u32 __force)value); } /** diff --git a/lib/nlattr.c b/lib/nlattr.c index b42b8577fc23..2988b08a7e4d 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -548,6 +548,24 @@ int nla_put(struct sk_buff *skb, int attrtype, int attrlen, const void *data) } EXPORT_SYMBOL(nla_put); +int nla_put_u8(struct sk_buff *skb, int attrtype, u8 value) +{ + return nla_put(skb, attrtype, sizeof(u8), &value); +} +EXPORT_SYMBOL(nla_put_u8); + +int nla_put_u16(struct sk_buff *skb, int attrtype, u16 value) +{ + return nla_put(skb, attrtype, sizeof(u16), &value); +} +EXPORT_SYMBOL(nla_put_u16); + +int nla_put_u32(struct sk_buff *skb, int attrtype, u32 value) +{ + return nla_put(skb, attrtype, sizeof(u32), &value); +} +EXPORT_SYMBOL(nla_put_u32); + /** * nla_put_64bit - Add a netlink attribute to a socket buffer and align it * @skb: socket buffer to add attribute to -- 2.9.0