[linux-next:master 4040/7019] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement

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* [linux-next:master 4040/7019] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement
@ 2022-06-30 18:23 kernel test robot
  2022-06-30 21:01 ` Paul E. McKenney
  0 siblings, 1 reply; 4+ messages in thread
From: kernel test robot @ 2022-06-30 18:23 UTC (permalink / raw)
  To: Frederic Weisbecker
  Cc: kbuild-all, Linux Memory Management List, Paul E. McKenney,
	Nicolas Saenz Julienne

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   6cc11d2a1759275b856e464265823d94aabd5eaf
commit: 408c74a2d8f01262e152b7eb09500033fbe6bafe [4040/7019] context_tracking: Convert state to atomic_t
config: powerpc-amigaone_defconfig (https://download.01.org/0day-ci/archive/20220701/202207010213.PDJ0d9Vj-lkp@intel.com/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=408c74a2d8f01262e152b7eb09500033fbe6bafe
        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 408c74a2d8f01262e152b7eb09500033fbe6bafe
        # 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

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

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


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, &current_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@gmail.com>
:::::: CC: Michael Ellerman <mpe@ellerman.id.au>

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [linux-next:master 4040/7019] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement
  2022-06-30 18:23 [linux-next:master 4040/7019] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement kernel test robot
@ 2022-06-30 21:01 ` Paul E. McKenney
  2022-07-01 10:11   ` [kbuild-all] " Chen, Rong A
  0 siblings, 1 reply; 4+ messages in thread
From: Paul E. McKenney @ 2022-06-30 21:01 UTC (permalink / raw)
  To: kernel test robot
  Cc: Frederic Weisbecker, kbuild-all, Linux Memory Management List,
	Nicolas Saenz Julienne

On Fri, Jul 01, 2022 at 02:23:30AM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   6cc11d2a1759275b856e464265823d94aabd5eaf
> commit: 408c74a2d8f01262e152b7eb09500033fbe6bafe [4040/7019] context_tracking: Convert state to atomic_t
> config: powerpc-amigaone_defconfig (https://download.01.org/0day-ci/archive/20220701/202207010213.PDJ0d9Vj-lkp@intel.com/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=408c74a2d8f01262e152b7eb09500033fbe6bafe
>         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 408c74a2d8f01262e152b7eb09500033fbe6bafe
>         # 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
> 
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@intel.com>

Good catch!  Does the updated commit 344e00943785 ("context_tracking:
Convert state to atomic_t") address this issue?

							Thanx, Paul

> 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
> 
> 
> 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, &current_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@gmail.com>
> :::::: CC: Michael Ellerman <mpe@ellerman.id.au>
> 
> -- 
> 0-DAY CI Kernel Test Service
> https://01.org/lkp


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [kbuild-all] Re: [linux-next:master 4040/7019] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement
  2022-06-30 21:01 ` Paul E. McKenney
@ 2022-07-01 10:11   ` Chen, Rong A
  2022-07-01 13:51     ` Paul E. McKenney
  0 siblings, 1 reply; 4+ messages in thread
From: Chen, Rong A @ 2022-07-01 10:11 UTC (permalink / raw)
  To: paulmck, kernel test robot
  Cc: Frederic Weisbecker, kbuild-all, Linux Memory Management List,
	Nicolas Saenz Julienne



On 7/1/2022 5:01 AM, Paul E. McKenney wrote:
> On Fri, Jul 01, 2022 at 02:23:30AM +0800, kernel test robot wrote:
>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
>> head:   6cc11d2a1759275b856e464265823d94aabd5eaf
>> commit: 408c74a2d8f01262e152b7eb09500033fbe6bafe [4040/7019] context_tracking: Convert state to atomic_t
>> config: powerpc-amigaone_defconfig (https://download.01.org/0day-ci/archive/20220701/202207010213.PDJ0d9Vj-lkp@intel.com/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=408c74a2d8f01262e152b7eb09500033fbe6bafe
>>          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 408c74a2d8f01262e152b7eb09500033fbe6bafe
>>          # 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
>>
>> If you fix the issue, kindly add following tag where applicable
>> Reported-by: kernel test robot <lkp@intel.com>
> 
> Good catch!  Does the updated commit 344e00943785 ("context_tracking:
> Convert state to atomic_t") address this issue?
> 
> 							Thanx, Paul

Hi Paul,

Yes, I have confirmed that there's no such issue on commit 344e00943785.

Best Regards,
Rong Chen

> 
>> 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
>>
>>
>> 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, &current_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@gmail.com>
>> :::::: CC: Michael Ellerman <mpe@ellerman.id.au>
>>
>> -- 
>> 0-DAY CI Kernel Test Service
>> https://01.org/lkp
> _______________________________________________
> kbuild-all mailing list -- kbuild-all@lists.01.org
> To unsubscribe send an email to kbuild-all-leave@lists.01.org
> 


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [kbuild-all] Re: [linux-next:master 4040/7019] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement
  2022-07-01 10:11   ` [kbuild-all] " Chen, Rong A
@ 2022-07-01 13:51     ` Paul E. McKenney
  0 siblings, 0 replies; 4+ messages in thread
From: Paul E. McKenney @ 2022-07-01 13:51 UTC (permalink / raw)
  To: Chen, Rong A
  Cc: kernel test robot, Frederic Weisbecker, kbuild-all,
	Linux Memory Management List, Nicolas Saenz Julienne

On Fri, Jul 01, 2022 at 06:11:31PM +0800, Chen, Rong A wrote:
> 
> 
> On 7/1/2022 5:01 AM, Paul E. McKenney wrote:
> > On Fri, Jul 01, 2022 at 02:23:30AM +0800, kernel test robot wrote:
> > > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> > > head:   6cc11d2a1759275b856e464265823d94aabd5eaf
> > > commit: 408c74a2d8f01262e152b7eb09500033fbe6bafe [4040/7019] context_tracking: Convert state to atomic_t
> > > config: powerpc-amigaone_defconfig (https://download.01.org/0day-ci/archive/20220701/202207010213.PDJ0d9Vj-lkp@intel.com/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=408c74a2d8f01262e152b7eb09500033fbe6bafe
> > >          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 408c74a2d8f01262e152b7eb09500033fbe6bafe
> > >          # 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
> > > 
> > > If you fix the issue, kindly add following tag where applicable
> > > Reported-by: kernel test robot <lkp@intel.com>
> > 
> > Good catch!  Does the updated commit 344e00943785 ("context_tracking:
> > Convert state to atomic_t") address this issue?
> > 
> > 							Thanx, Paul
> 
> Hi Paul,
> 
> Yes, I have confirmed that there's no such issue on commit 344e00943785.

Thank you!

							Thanx, Paul

> Best Regards,
> Rong Chen
> 
> > 
> > > 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
> > > 
> > > 
> > > 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, &current_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@gmail.com>
> > > :::::: CC: Michael Ellerman <mpe@ellerman.id.au>
> > > 
> > > -- 
> > > 0-DAY CI Kernel Test Service
> > > https://01.org/lkp
> > _______________________________________________
> > kbuild-all mailing list -- kbuild-all@lists.01.org
> > To unsubscribe send an email to kbuild-all-leave@lists.01.org
> > 


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2022-07-01 13:51 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-06-30 18:23 [linux-next:master 4040/7019] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement kernel test robot
2022-06-30 21:01 ` Paul E. McKenney
2022-07-01 10:11   ` [kbuild-all] " Chen, Rong A
2022-07-01 13:51     ` Paul E. McKenney

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