tree: https://github.com/0day-ci/linux/commits/UPDATE-20200911-024129/Borislav-... head: 730776685aa51f334b6186924ad8fb8ae8e10608 commit: 730776685aa51f334b6186924ad8fb8ae8e10608 [1/1] x86/mce: Make mce_rdmsrl() panic on an inaccessible MSR config: x86_64-allyesconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 reproduce (this is a W=1 build): git checkout 730776685aa51f334b6186924ad8fb8ae8e10608 # save the attached .config to linux build tree make W=1 ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): 373 | __visible bool ex_handler_rdmsr_fault(const struct exception_table_entry *fixup, | ^~~~~~~~~~~~~~~~~~~~~~ 418 | __visible bool ex_handler_wrmsr_fault(const struct exception_table_entry *fixup, | ^~~~~~~~~~~~~~~~~~~~~~ # https://github.com/0day-ci/linux/commit/730776685aa51f334b6186924ad8fb8ae... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review UPDATE-20200911-024129/Borislav-Petkov/x86-mce-Make-mce_rdmsrl-do-a-plain-RDMSR-only/20200907-111756 git checkout 730776685aa51f334b6186924ad8fb8ae8e10608 vim +/ex_handler_rdmsr_fault +373 arch/x86/kernel/cpu/mce/core.c 372 374 struct pt_regs *regs, int trapnr, 375 unsigned long error_code, 376 unsigned long fault_addr) 377 { 378 pr_emerg("MSR access error: RDMSR from 0x%x at rIP: 0x%lx (%pS)\n", 379 (unsigned int)regs->cx, regs->ip, (void *)regs->ip); 380 381 show_stack_regs(regs); 382 383 panic("MCA architectural violation!\n"); 384 385 while (true) 386 cpu_relax(); 387 388 return true; 389 } 390 391 /* MSR access wrappers used for error injection */ 392 static u64 mce_rdmsrl(u32 msr) 393 { 394 DECLARE_ARGS(val, low, high); 395 396 if (__this_cpu_read(injectm.finished)) { 397 int offset = msr_to_offset(msr); 398 399 if (offset < 0) 400 return 0; 401 return *(u64 *)((char *)this_cpu_ptr(&injectm) + offset); 402 } 403 404 /* 405 * RDMSR on MCA MSRs should not fault. If they do, this is very much an 406 * architectural violation and needs to be reported to hw vendor. Panic 407 * the box to not allow any further progress. 408 */ 409 asm volatile("1: rdmsr\n" 410 "2:\n" 411 _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_rdmsr_fault) 412 : EAX_EDX_RET(val, low, high) : "c" (msr)); 413 414 415 return EAX_EDX_VAL(val, low, high); 416 } 417 419 struct pt_regs *regs, int trapnr, 420 unsigned long error_code, 421 unsigned long fault_addr) 422 { 423 pr_emerg("MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x) at rIP: 0x%lx (%pS)\n", 424 (unsigned int)regs->cx, (unsigned int)regs->dx, (unsigned int)regs->ax, 425 regs->ip, (void *)regs->ip); 426 427 show_stack_regs(regs); 428 429 panic("MCA architectural violation!\n"); 430 431 while (true) 432 cpu_relax(); 433 434 return true; 435 } 436 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org