On Thu, Jun 23, 2022 at 04:50:49PM +0800, kernel test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master > head: 08897940f458ee55416cf80ab13d2d8b9f20038e > commit: 620ac34fef9e21aa2fd4aed6e01eed2e4fc605d4 [4204/5575] context_tracking: Convert state to atomic_t > config: powerpc-mgcoge_defconfig (https://download.01.org/0day-ci/archive/20220623/202206231654.cuANhsQq-lkp@xxxxxxxxx/config) > compiler: powerpc-linux-gcc (GCC) 11.3.0 > reproduce (this is a W=1 build): > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=620ac34fef9e21aa2fd4aed6e01eed2e4fc605d4 > git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git > git fetch --no-tags linux-next master > git checkout 620ac34fef9e21aa2fd4aed6e01eed2e4fc605d4 > # save the config file > mkdir build_dir && cp config build_dir/.config > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash arch/powerpc/kernel/ > > If you fix the issue, kindly add following tag where applicable > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > All errors (new ones prefixed by >>): > > arch/powerpc/kernel/interrupt.c: In function 'interrupt_exit_kernel_prepare': > >> arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement [-Werror=empty-body] > 542 | CT_WARN_ON(ct_state() == CONTEXT_USER); > | ^ > cc1: all warnings being treated as errors This is a bit odd, and perhaps should instead be written as follows: WARN_ON_ONCE(TRAP(regs) != INTERRUPT_PROGRAM && CT_WARN_ON(ct_state() == CONTEXT_USER)); But this code has been around for awhile, and was not changed by the commit called out above. I will let the PowerPC guys choose what they want to do with it. Thanx, Paul > vim +/if +542 arch/powerpc/kernel/interrupt.c > > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 527 > bf9155f1970c4d arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 528 notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs) > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 529 { > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 530 unsigned long flags; > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 531 unsigned long ret = 0; > ad2d2344771dab arch/powerpc/kernel/interrupt.c Christophe Leroy 2021-03-12 532 unsigned long kuap; > 985faa78687de6 arch/powerpc/kernel/interrupt.c Mark Rutland 2021-11-29 533 bool stack_store = read_thread_flags() & _TIF_EMULATE_STACK_STORE; > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 534 > 806c0e6e7e97ad arch/powerpc/kernel/interrupt.c Christophe Leroy 2021-08-23 535 if (regs_is_unrecoverable(regs)) > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 536 unrecoverable_exception(regs); > f821bc97dee4f3 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2021-01-30 537 /* > f821bc97dee4f3 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2021-01-30 538 * CT_WARN_ON comes here via program_check_exception, > f821bc97dee4f3 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2021-01-30 539 * so avoid recursion. > f821bc97dee4f3 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2021-01-30 540 */ > 7153d4bf0b3734 arch/powerpc/kernel/interrupt.c Xiongwei Song 2021-04-14 541 if (TRAP(regs) != INTERRUPT_PROGRAM) > f821bc97dee4f3 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2021-01-30 @542 CT_WARN_ON(ct_state() == CONTEXT_USER); > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 543 > ad2d2344771dab arch/powerpc/kernel/interrupt.c Christophe Leroy 2021-03-12 544 kuap = kuap_get_and_assert_locked(); > c0d7dcf89e5151 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-04-29 545 > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 546 local_irq_save(flags); > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 547 > 344bb20b159dd0 arch/powerpc/kernel/interrupt.c Christophe Leroy 2021-02-08 548 if (!arch_irq_disabled_regs(regs)) { > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 549 /* Returning to a kernel context with local irqs enabled. */ > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 550 WARN_ON_ONCE(!(regs->msr & MSR_EE)); > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 551 again: > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 552 if (IS_ENABLED(CONFIG_PREEMPT)) { > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 553 /* Return to preemptible kernel context */ > 985faa78687de6 arch/powerpc/kernel/interrupt.c Mark Rutland 2021-11-29 554 if (unlikely(read_thread_flags() & _TIF_NEED_RESCHED)) { > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 555 if (preempt_count() == 0) > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 556 preempt_schedule_irq(); > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 557 } > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 558 } > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 559 > 6eaaf9de359986 arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-22 560 check_return_regs_valid(regs); > 6eaaf9de359986 arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-22 561 > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 562 /* > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 563 * Stack store exit can't be restarted because the interrupt > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 564 * stack frame might have been clobbered. > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 565 */ > 61eece2d170779 arch/powerpc/kernel/interrupt.c Christophe Leroy 2021-06-18 566 if (!prep_irq_for_enabled_exit(unlikely(stack_store))) { > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 567 /* > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 568 * Replay pending soft-masked interrupts now. Don't > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 569 * just local_irq_enabe(); local_irq_disable(); because > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 570 * if we are returning from an asynchronous interrupt > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 571 * here, another one might hit after irqs are enabled, > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 572 * and it would exit via this same path allowing > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 573 * another to fire, and so on unbounded. > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 574 */ > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 575 hard_irq_disable(); > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 576 replay_soft_interrupts(); > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 577 /* Took an interrupt, may have more exit work to do. */ > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 578 goto again; > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 579 } > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 580 #ifdef CONFIG_PPC64 > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 581 /* > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 582 * An interrupt may clear MSR[EE] and set this concurrently, > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 583 * but it will be marked pending and the exit will be retried. > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 584 * This leaves a racy window where MSR[EE]=0 and HARD_DIS is > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 585 * clear, until interrupt_exit_kernel_restart() calls > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 586 * hard_irq_disable(), which will set HARD_DIS again. > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 587 */ > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 588 local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS; > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 589 > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 590 } else { > 6eaaf9de359986 arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-22 591 check_return_regs_valid(regs); > 6eaaf9de359986 arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-22 592 > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 593 if (unlikely(stack_store)) > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 594 __hard_EE_RI_disable(); > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 595 /* > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 596 * Returning to a kernel context with local irqs disabled. > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 597 * Here, if EE was enabled in the interrupted context, enable > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 598 * it on return as well. A problem exists here where a soft > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 599 * masked interrupt may have cleared MSR[EE] and set HARD_DIS > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 600 * here, and it will still exist on return to the caller. This > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 601 * will be resolved by the masked interrupt firing again. > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 602 */ > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 603 if (regs->msr & MSR_EE) > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 604 local_paca->irq_happened &= ~PACA_IRQ_HARD_DIS; > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 605 #endif /* CONFIG_PPC64 */ > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 606 } > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 607 > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 608 if (unlikely(stack_store)) { > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 609 clear_bits(_TIF_EMULATE_STACK_STORE, ¤t_thread_info()->flags); > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 610 ret = 1; > 13799748b957bc arch/powerpc/kernel/interrupt.c Nicholas Piggin 2021-06-18 611 } > 6cc0c16d82f889 arch/powerpc/kernel/syscall_64.c Nicholas Piggin 2020-02-26 612 > > :::::: The code at line 542 was first introduced by commit > :::::: f821bc97dee4f3ee92c3668d495af49dfd720fe0 powerpc/64s: move context tracking exit to interrupt exit path > > :::::: TO: Nicholas Piggin <npiggin@xxxxxxxxx> > :::::: CC: Michael Ellerman <mpe@xxxxxxxxxxxxxx> > > -- > 0-DAY CI Kernel Test Service > https://01.org/lkp
