Re: [PATCH 1/9] x86/cet: Control protection exception handler

From: kbuild test robot
Date: Fri Jun 08 2018 - 00:19:05 EST


Hi Yu-cheng,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on asm-generic/master]
[also build test ERROR on v4.17 next-20180607]
[cannot apply to tip/x86/core mmotm/master]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/Yu-cheng-Yu/Control-Flow-Enforcement-Part-2/20180608-111152
base: https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git master
config: i386-tinyconfig (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
# save the attached .config to linux build tree
make ARCH=i386

All errors (new ones prefixed by >>):

In file included from arch/x86/include/asm/thread_info.h:53:0,
from include/linux/thread_info.h:38,
from arch/x86/include/asm/preempt.h:7,
from include/linux/preempt.h:81,
from include/linux/rcupdate.h:40,
from include/linux/rculist.h:11,
from include/linux/pid.h:5,
from include/linux/sched.h:14,
from include/linux/context_tracking.h:5,
from arch/x86/kernel/traps.c:15:
arch/x86/kernel/traps.c: In function 'do_control_protection':
>> arch/x86/kernel/traps.c:605:27: error: 'X86_FEATURE_SHSTK' undeclared (first use in this function); did you mean 'X86_FEATURE_EST'?
if (!cpu_feature_enabled(X86_FEATURE_SHSTK) &&
^
arch/x86/include/asm/cpufeature.h:127:24: note: in definition of macro 'cpu_feature_enabled'
(__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
^~~
arch/x86/kernel/traps.c:605:27: note: each undeclared identifier is reported only once for each function it appears in
if (!cpu_feature_enabled(X86_FEATURE_SHSTK) &&
^
arch/x86/include/asm/cpufeature.h:127:24: note: in definition of macro 'cpu_feature_enabled'
(__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
^~~
>> arch/x86/kernel/traps.c:606:27: error: 'X86_FEATURE_IBT' undeclared (first use in this function); did you mean 'X86_FEATURE_IBS'?
!cpu_feature_enabled(X86_FEATURE_IBT)) {
^
arch/x86/include/asm/cpufeature.h:127:24: note: in definition of macro 'cpu_feature_enabled'
(__builtin_constant_p(bit) && DISABLED_MASK_BIT_SET(bit) ? 0 : static_cpu_has(bit))
^~~

vim +605 arch/x86/kernel/traps.c

589
590 /*
591 * When a control protection exception occurs, send a signal
592 * to the responsible application. Currently, control
593 * protection is only enabled for the user mode. This
594 * exception should not come from the kernel mode.
595 */
596 dotraplinkage void
597 do_control_protection(struct pt_regs *regs, long error_code)
598 {
599 struct task_struct *tsk;
600
601 RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
602 cond_local_irq_enable(regs);
603
604 tsk = current;
> 605 if (!cpu_feature_enabled(X86_FEATURE_SHSTK) &&
> 606 !cpu_feature_enabled(X86_FEATURE_IBT)) {
607 goto exit;
608 }
609
610 if (!user_mode(regs)) {
611 tsk->thread.error_code = error_code;
612 tsk->thread.trap_nr = X86_TRAP_CP;
613 if (notify_die(DIE_TRAP, "control protection fault", regs,
614 error_code, X86_TRAP_CP, SIGSEGV) != NOTIFY_STOP)
615 die("control protection fault", regs, error_code);
616 return;
617 }
618
619 tsk->thread.error_code = error_code;
620 tsk->thread.trap_nr = X86_TRAP_CP;
621
622 if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
623 printk_ratelimit()) {
624 unsigned int max_idx, err_idx;
625
626 max_idx = ARRAY_SIZE(control_protection_err) - 1;
627 err_idx = min((unsigned int)error_code - 1, max_idx);
628 pr_info("%s[%d] control protection ip:%lx sp:%lx error:%lx(%s)",
629 tsk->comm, task_pid_nr(tsk),
630 regs->ip, regs->sp, error_code,
631 control_protection_err[err_idx]);
632 print_vma_addr(" in ", regs->ip);
633 pr_cont("\n");
634 }
635
636 exit:
637 force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
638 }
639 NOKPROBE_SYMBOL(do_control_protection);
640

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