tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 6fd3ec5c7af58d5d6b598fba22ac387645af33f4 commit: d1721250f3ffed9afba3e1fb729947cec64c5a8a x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into C date: 1 year, 3 months ago config: i386-randconfig-r036-20210927 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d1721250f3ffed9afba3e1fb729947cec64c5a8a git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout d1721250f3ffed9afba3e1fb729947cec64c5a8a # save the attached .config to linux build tree make W=1 ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): arch/x86/entry/common.c:280:24: warning: no previous prototype for 'prepare_exit_to_usermode' [-Wmissing-prototypes] 280 | __visible noinstr void prepare_exit_to_usermode(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~~~~~~~ arch/x86/entry/common.c:342:24: warning: no previous prototype for 'syscall_return_slowpath' [-Wmissing-prototypes] 342 | __visible noinstr void syscall_return_slowpath(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~~~~~~ arch/x86/entry/common.c:418:24: warning: no previous prototype for 'do_int80_syscall_32' [-Wmissing-prototypes] 418 | __visible noinstr void do_int80_syscall_32(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~~ arch/x86/entry/common.c:463:24: warning: no previous prototype for 'do_fast_syscall_32' [-Wmissing-prototypes] 463 | __visible noinstr long do_fast_syscall_32(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~ >> arch/x86/entry/common.c:527:24: warning: no previous prototype for 'do_SYSENTER_32' [-Wmissing-prototypes] 527 | __visible noinstr long do_SYSENTER_32(struct pt_regs *regs) | ^~~~~~~~~~~~~~ vim +/do_SYSENTER_32 +527 arch/x86/entry/common.c 525 526 /* Returns 0 to return using IRET or 1 to return using SYSEXIT/SYSRETL. */ > 527 __visible noinstr long do_SYSENTER_32(struct pt_regs *regs) 528 { 529 /* SYSENTER loses RSP, but the vDSO saved it in RBP. */ 530 regs->sp = regs->bp; 531 532 /* SYSENTER clobbers EFLAGS.IF. Assume it was set in usermode. */ 533 regs->flags |= X86_EFLAGS_IF; 534 535 return do_fast_syscall_32(regs); 536 } 537 #endif 538 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org