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* [linux-next:master 4204/5575] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement
@ 2022-06-23  8:50 kernel test robot
  2022-06-24  2:52 ` Paul E. McKenney
  0 siblings, 1 reply; 4+ messages in thread
From: kernel test robot @ 2022-06-23  8:50 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:   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@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=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@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 4204/5575] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement
  2022-06-23  8:50 [linux-next:master 4204/5575] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement kernel test robot
@ 2022-06-24  2:52 ` Paul E. McKenney
  2022-06-24  5:47   ` Christophe Leroy
  0 siblings, 1 reply; 4+ messages in thread
From: Paul E. McKenney @ 2022-06-24  2:52 UTC (permalink / raw)
  To: kernel test robot
  Cc: Frederic Weisbecker, kbuild-all, Linux Memory Management List,
	Nicolas Saenz Julienne

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@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=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@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

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, &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 4204/5575] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement
  2022-06-24  2:52 ` Paul E. McKenney
@ 2022-06-24  5:47   ` Christophe Leroy
  2022-06-24 12:57     ` Paul E. McKenney
  0 siblings, 1 reply; 4+ messages in thread
From: Christophe Leroy @ 2022-06-24  5:47 UTC (permalink / raw)
  To: paulmck, kernel test robot
  Cc: Frederic Weisbecker, kbuild-all, Linux Memory Management List,
	Nicolas Saenz Julienne



Le 24/06/2022 à 04:52, Paul E. McKenney a écrit :
> 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@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=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@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
> 
> 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.


The commit called out above did a change. It added:

	#define CT_WARN_ON(cond)

When CONFIG_CONTEXT_TRACKING_USER is not defined


That change is wrong, it should be:

	#define CT_WARN_ON(cond)	do { } while (0)


Christophe

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [linux-next:master 4204/5575] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement
  2022-06-24  5:47   ` Christophe Leroy
@ 2022-06-24 12:57     ` Paul E. McKenney
  0 siblings, 0 replies; 4+ messages in thread
From: Paul E. McKenney @ 2022-06-24 12:57 UTC (permalink / raw)
  To: Christophe Leroy
  Cc: kernel test robot, Frederic Weisbecker, kbuild-all,
	Linux Memory Management List, Nicolas Saenz Julienne

On Fri, Jun 24, 2022 at 05:47:54AM +0000, Christophe Leroy wrote:
> 
> 
> Le 24/06/2022 à 04:52, Paul E. McKenney a écrit :
> > 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@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=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@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
> > 
> > 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.
> 
> 
> The commit called out above did a change. It added:
> 
> 	#define CT_WARN_ON(cond)
> 
> When CONFIG_CONTEXT_TRACKING_USER is not defined
> 
> 
> That change is wrong, it should be:
> 
> 	#define CT_WARN_ON(cond)	do { } while (0)

Ah, thank you.  Will fix.

							Thanx, Paul


^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-06-24 12:57 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-06-23  8:50 [linux-next:master 4204/5575] arch/powerpc/kernel/interrupt.c:542:55: error: suggest braces around empty body in an 'if' statement kernel test robot
2022-06-24  2:52 ` Paul E. McKenney
2022-06-24  5:47   ` Christophe Leroy
2022-06-24 12:57     ` Paul E. McKenney

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