include/linux/netlink.h:115:6: warning: ' conflicts with existing pseudo(MASK) entry for TOS mask ' directive output truncated writing 57 bytes into a region of size between 33 and 39

From: kernel test robot
Date: Tue Sep 19 2023 - 15:10:13 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 2cf0f715623872823a72e451243bbf555d10d032
commit: 3c9561c0a5b988be3dfd24ea1de2301b95efc640 sfc: support TC decap rules matching on enc_ip_tos
date: 4 months ago
config: x86_64-randconfig-014-20230906 (https://download.01.org/0day-ci/archive/20230920/202309200308.Eu2HF6Md-lkp@xxxxxxxxx/config)
compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230920/202309200308.Eu2HF6Md-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309200308.Eu2HF6Md-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

In file included from include/uapi/linux/neighbour.h:6:0,
from include/linux/netdevice.h:46,
from include/net/sch_generic.h:5,
from include/net/pkt_cls.h:7,
from drivers/net/ethernet/sfc/tc.c:12:
drivers/net/ethernet/sfc/tc.c: In function 'efx_tc_flower_record_encap_match':
>> include/linux/netlink.h:115:6: warning: ' conflicts with existing pseudo(MASK) entry for TOS mask ' directive output truncated writing 57 bytes into a region of size between 33 and 39 [-Wformat-truncation=]
if (snprintf(__extack->_msg_buf, NETLINK_MAX_FMTMSG_LEN, \
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"%s" fmt "%s", "", ##args, "") >= \
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/netlink.h:130:2: note: in expansion of macro 'NL_SET_ERR_MSG_FMT'
NL_SET_ERR_MSG_FMT((extack), KBUILD_MODNAME ": " fmt, ##args)
^~~~~~~~~~~~~~~~~~
drivers/net/ethernet/sfc/tc.c:507:5: note: in expansion of macro 'NL_SET_ERR_MSG_FMT_MOD'
NL_SET_ERR_MSG_FMT_MOD(extack,
^~~~~~~~~~~~~~~~~~~~~~
include/linux/netlink.h:115:6: note: directive argument in the range [0, 2147483647]
if (snprintf(__extack->_msg_buf, NETLINK_MAX_FMTMSG_LEN, \
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"%s" fmt "%s", "", ##args, "") >= \
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/netlink.h:130:2: note: in expansion of macro 'NL_SET_ERR_MSG_FMT'
NL_SET_ERR_MSG_FMT((extack), KBUILD_MODNAME ": " fmt, ##args)
^~~~~~~~~~~~~~~~~~
drivers/net/ethernet/sfc/tc.c:507:5: note: in expansion of macro 'NL_SET_ERR_MSG_FMT_MOD'
NL_SET_ERR_MSG_FMT_MOD(extack,
^~~~~~~~~~~~~~~~~~~~~~
include/linux/netlink.h:115:6: note: 'snprintf' output between 103 and 115 bytes into a destination of size 80
if (snprintf(__extack->_msg_buf, NETLINK_MAX_FMTMSG_LEN, \
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"%s" fmt "%s", "", ##args, "") >= \
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/netlink.h:130:2: note: in expansion of macro 'NL_SET_ERR_MSG_FMT'
NL_SET_ERR_MSG_FMT((extack), KBUILD_MODNAME ": " fmt, ##args)
^~~~~~~~~~~~~~~~~~
drivers/net/ethernet/sfc/tc.c:507:5: note: in expansion of macro 'NL_SET_ERR_MSG_FMT_MOD'
NL_SET_ERR_MSG_FMT_MOD(extack,
^~~~~~~~~~~~~~~~~~~~~~


vim +115 include/linux/netlink.h

2d4bc93368f5a0 Johannes Berg 2017-04-12 106
51c352bdbcd23d Edward Cree 2022-10-18 107 /* We splice fmt with %s at each end even in the snprintf so that both calls
51c352bdbcd23d Edward Cree 2022-10-18 108 * can use the same string constant, avoiding its duplication in .ro
51c352bdbcd23d Edward Cree 2022-10-18 109 */
51c352bdbcd23d Edward Cree 2022-10-18 110 #define NL_SET_ERR_MSG_FMT(extack, fmt, args...) do { \
51c352bdbcd23d Edward Cree 2022-10-18 111 struct netlink_ext_ack *__extack = (extack); \
51c352bdbcd23d Edward Cree 2022-10-18 112 \
51c352bdbcd23d Edward Cree 2022-10-18 113 if (!__extack) \
51c352bdbcd23d Edward Cree 2022-10-18 114 break; \
51c352bdbcd23d Edward Cree 2022-10-18 @115 if (snprintf(__extack->_msg_buf, NETLINK_MAX_FMTMSG_LEN, \
51c352bdbcd23d Edward Cree 2022-10-18 116 "%s" fmt "%s", "", ##args, "") >= \
51c352bdbcd23d Edward Cree 2022-10-18 117 NETLINK_MAX_FMTMSG_LEN) \
51c352bdbcd23d Edward Cree 2022-10-18 118 net_warn_ratelimited("%s" fmt "%s", "truncated extack: ", \
51c352bdbcd23d Edward Cree 2022-10-18 119 ##args, "\n"); \
51c352bdbcd23d Edward Cree 2022-10-18 120 \
51c352bdbcd23d Edward Cree 2022-10-18 121 do_trace_netlink_extack(__extack->_msg_buf); \
51c352bdbcd23d Edward Cree 2022-10-18 122 \
51c352bdbcd23d Edward Cree 2022-10-18 123 __extack->_msg = __extack->_msg_buf; \
51c352bdbcd23d Edward Cree 2022-10-18 124 } while (0)
51c352bdbcd23d Edward Cree 2022-10-18 125

:::::: The code at line 115 was first introduced by commit
:::::: 51c352bdbcd23d7ce46b06c1e64c82754dc44044 netlink: add support for formatted extack messages

:::::: TO: Edward Cree <ecree.xilinx@xxxxxxxxx>
:::::: CC: Jakub Kicinski <kuba@xxxxxxxxxx>

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