Hi Neal, [auto build test ERROR on net-next/master] url: https://github.com/0day-ci/linux/commits/Neal-Cardwell/tcp-BBR-congestion-control-algorithm/20160917-025323 config: x86_64-randconfig-x006-201637 (attached as .config) compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 All errors (new ones prefixed by >>): >> net/ipv4/tcp_cdg.c:59:8: error: redefinition of 'struct minmax' struct minmax { ^~~~~~ In file included from include/linux/tcp.h:22:0, from include/net/tcp.h:24, from net/ipv4/tcp_cdg.c:30: include/linux/win_minmax.h:17:8: note: originally defined here struct minmax { ^~~~~~ vim +59 net/ipv4/tcp_cdg.c 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 43 module_param(window, int, 0444); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 44 MODULE_PARM_DESC(window, "gradient window size (power of two <= 256)"); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 45 module_param(backoff_beta, uint, 0644); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 46 MODULE_PARM_DESC(backoff_beta, "backoff beta (0-1024)"); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 47 module_param(backoff_factor, uint, 0644); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 48 MODULE_PARM_DESC(backoff_factor, "backoff probability scale factor"); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 49 module_param(hystart_detect, uint, 0644); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 50 MODULE_PARM_DESC(hystart_detect, "use Hybrid Slow start " 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 51 "(0: disabled, 1: ACK train, 2: delay threshold, 3: both)"); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 52 module_param(use_ineff, uint, 0644); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 53 MODULE_PARM_DESC(use_ineff, "use ineffectual backoff detection (threshold)"); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 54 module_param(use_shadow, bool, 0644); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 55 MODULE_PARM_DESC(use_shadow, "use shadow window heuristic"); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 56 module_param(use_tolerance, bool, 0644); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 57 MODULE_PARM_DESC(use_tolerance, "use loss tolerance heuristic"); 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 58 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 @59 struct minmax { 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 60 union { 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 61 struct { 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 62 s32 min; 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 63 s32 max; 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 64 }; 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 65 u64 v64; 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 66 }; 2b0a8c9e Kenneth Klette Jonassen 2015-06-10 67 }; :::::: The code at line 59 was first introduced by commit :::::: 2b0a8c9eee81882fc0001ccf6d9af62cdc682f9e tcp: add CDG congestion control :::::: TO: Kenneth Klette Jonassen :::::: CC: David S. Miller --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation