search for: raw_local_irq_save

On 11.08.20 09:41, Peter Zijlstra wrote: > On Fri, Aug 07, 2020 at 05:19:03PM +0200, Marco Elver wrote: > >> My hypothesis here is simply that kvm_wait() may be called in a place >> where we get the same case I mentioned to Peter, >> >> raw_local_irq_save(); /* or other IRQs off without tracing */ >> ... >> kvm_wait() /* IRQ state tracing gets confused */ >> ... >> raw_local_irq_restore(); >> >> and therefore, using raw variants in kvm_wait() works. It's also safe >> because it doesn't call any o...

On 11.08.20 09:41, Peter Zijlstra wrote: > On Fri, Aug 07, 2020 at 05:19:03PM +0200, Marco Elver wrote: > >> My hypothesis here is simply that kvm_wait() may be called in a place >> where we get the same case I mentioned to Peter, >> >> raw_local_irq_save(); /* or other IRQs off without tracing */ >> ... >> kvm_wait() /* IRQ state tracing gets confused */ >> ... >> raw_local_irq_restore(); >> >> and therefore, using raw variants in kvm_wait() works. It's also safe >> because it doesn't call any o...

...1, Peter Zijlstra wrote: >>> On Fri, Aug 07, 2020 at 05:19:03PM +0200, Marco Elver wrote: >>> >>>> My hypothesis here is simply that kvm_wait() may be called in a place >>>> where we get the same case I mentioned to Peter, >>>> >>>> raw_local_irq_save(); /* or other IRQs off without tracing */ >>>> ... >>>> kvm_wait() /* IRQ state tracing gets confused */ >>>> ... >>>> raw_local_irq_restore(); >>>> >>>> and therefore, using raw variants in kvm_wait() works. It's also...

...1, Peter Zijlstra wrote: >>> On Fri, Aug 07, 2020 at 05:19:03PM +0200, Marco Elver wrote: >>> >>>> My hypothesis here is simply that kvm_wait() may be called in a place >>>> where we get the same case I mentioned to Peter, >>>> >>>> raw_local_irq_save(); /* or other IRQs off without tracing */ >>>> ... >>>> kvm_wait() /* IRQ state tracing gets confused */ >>>> ... >>>> raw_local_irq_restore(); >>>> >>>> and therefore, using raw variants in kvm_wait() works. It's also...

...gs. However, that was based on your pointer about kvm_wait(), and >> I can't quite tell if it is the right solution. >> >> My hypothesis here is simply that kvm_wait() may be called in a place >> where we get the same case I mentioned to Peter, >> >> raw_local_irq_save(); /* or other IRQs off without tracing */ >> ... >> kvm_wait() /* IRQ state tracing gets confused */ >> ... >> raw_local_irq_restore(); >> >> and therefore, using raw variants in kvm_wait() works. It's also safe >> b...

On Wed, Aug 05, 2020 at 03:59:40PM +0200, Marco Elver wrote: > On Wed, Aug 05, 2020 at 03:42PM +0200, peterz at infradead.org wrote: > > Shouldn't we __always_inline those? They're going to be really small. > > I can send a v2, and you can choose. For reference, though: > > ffffffff86271ee0 <arch_local_save_flags>: > ffffffff86271ee0: 0f 1f 44 00 00

On Wed, Aug 05, 2020 at 03:59:40PM +0200, Marco Elver wrote: > On Wed, Aug 05, 2020 at 03:42PM +0200, peterz at infradead.org wrote: > > Shouldn't we __always_inline those? They're going to be really small. > > I can send a v2, and you can choose. For reference, though: > > ffffffff86271ee0 <arch_local_save_flags>: > ffffffff86271ee0: 0f 1f 44 00 00

...> --- a/init/main.c > +++ b/init/main.c > @@ -1041,6 +1041,22 @@ asmlinkage __visible void __init start_kernel(void) > sfi_init_late(); > kcsan_init(); > > + /* DEBUG CODE */ > + lockdep_assert_irqs_enabled(); /* Pass. */ > + { > + unsigned long flags1; > + raw_local_irq_save(flags1); This disables IRQs but doesn't trace.. > + { > + unsigned long flags2; > + lockdep_assert_irqs_enabled(); /* Pass - expectedly blind. */ Indeed, we didn't trace the above disable, so software state is still on. > + local_irq_save(flags2); So here we save IRQ...

...s, the more > problems I keep finding... bah bah bah. That is, most of these irq-tracking problem are new because commit: 859d069ee1dd ("lockdep: Prepare for NMI IRQ state tracking") changed irq-tracking to ignore the lockdep recursion count. This then allows: lock_acquire() raw_local_irq_save(); current->lockdep_recursion++; trace_lock_acquire() ... tracing ... #PF under raw_local_irq_*() __lock_acquire() arch_spin_lock(&graph_lock) pv-spinlock-wait() local_irq_save() under raw_local_irq_*() However afaict that just made a bad situation w...

...s, the more > problems I keep finding... bah bah bah. That is, most of these irq-tracking problem are new because commit: 859d069ee1dd ("lockdep: Prepare for NMI IRQ state tracking") changed irq-tracking to ignore the lockdep recursion count. This then allows: lock_acquire() raw_local_irq_save(); current->lockdep_recursion++; trace_lock_acquire() ... tracing ... #PF under raw_local_irq_*() __lock_acquire() arch_spin_lock(&graph_lock) pv-spinlock-wait() local_irq_save() under raw_local_irq_*() However afaict that just made a bad situation w...

On Fri, Aug 07, 2020 at 05:19:03PM +0200, Marco Elver wrote: > My hypothesis here is simply that kvm_wait() may be called in a place > where we get the same case I mentioned to Peter, > > raw_local_irq_save(); /* or other IRQs off without tracing */ > ... > kvm_wait() /* IRQ state tracing gets confused */ > ... > raw_local_irq_restore(); > > and therefore, using raw variants in kvm_wait() works. It's also safe > because it doesn't call any other libraries that would r...

...signed long __raw_local_ return flags; } -#define raw_local_save_flags(flags) \ - do { (flags) = __raw_local_save_flags(); } while (0) static inline void raw_local_irq_restore(unsigned long flags) { @@ -100,8 +107,6 @@ static inline unsigned long __raw_local_ return flags; } -#define raw_local_irq_save(flags) \ - do { (flags) = __raw_local_irq_save(); } while (0) static inline int raw_irqs_disabled(void) { @@ -128,6 +133,7 @@ static inline void halt(void) __asm__ __volatile__("hlt": : :"memory"); } +#endif /* CONFIG_PARAVIRT */ #else /* __ASSEMBLY__: */ # ifdef CON...

...signed long __raw_local_ return flags; } -#define raw_local_save_flags(flags) \ - do { (flags) = __raw_local_save_flags(); } while (0) static inline void raw_local_irq_restore(unsigned long flags) { @@ -100,8 +107,6 @@ static inline unsigned long __raw_local_ return flags; } -#define raw_local_irq_save(flags) \ - do { (flags) = __raw_local_irq_save(); } while (0) static inline int raw_irqs_disabled(void) { @@ -128,6 +133,7 @@ static inline void halt(void) __asm__ __volatile__("hlt": : :"memory"); } +#endif /* CONFIG_PARAVIRT */ #else /* __ASSEMBLY__: */ # ifdef CON...

...1.08.20 09:41, Peter Zijlstra wrote: > > On Fri, Aug 07, 2020 at 05:19:03PM +0200, Marco Elver wrote: > > > > > My hypothesis here is simply that kvm_wait() may be called in a place > > > where we get the same case I mentioned to Peter, > > > > > > raw_local_irq_save(); /* or other IRQs off without tracing */ > > > ... > > > kvm_wait() /* IRQ state tracing gets confused */ > > > ... > > > raw_local_irq_restore(); > > > > > > and therefore, using raw variants in kvm_wait() works. It's also safe >...

Hi folks, Here is the result of the latest work on the pvops front, after the x86 arch merge. From the functionality point of view, almost nothing was changed, except for proper vsmp support - which was discussed, but not implemented before - and the introduction of smp_ops in x86_64, which eased the merging of the smp header. Speaking of the merge, a significant part (although not majority) of

Hi folks, Here is the result of the latest work on the pvops front, after the x86 arch merge. From the functionality point of view, almost nothing was changed, except for proper vsmp support - which was discussed, but not implemented before - and the introduction of smp_ops in x86_64, which eased the merging of the smp header. Speaking of the merge, a significant part (although not majority) of

...ot;); -} static inline int raw_irqs_disabled_flags(unsigned long flags) { @@ -76,18 +26,6 @@ static inline int raw_irqs_disabled(void unsigned long flags = __raw_local_save_flags(); return raw_irqs_disabled_flags(flags); -} - -/* - * For spinlocks, etc: - */ -static inline unsigned long __raw_local_irq_save(void) -{ - unsigned long flags = __raw_local_save_flags(); - - raw_local_irq_disable(); - - return flags; } #define raw_local_irq_save(flags) \ =================================================================== --- a/include/asm-i386/processor.h +++ b/include/asm-i386/processor.h @@ -20,6 +20,...

...ot;); -} static inline int raw_irqs_disabled_flags(unsigned long flags) { @@ -76,18 +26,6 @@ static inline int raw_irqs_disabled(void unsigned long flags = __raw_local_save_flags(); return raw_irqs_disabled_flags(flags); -} - -/* - * For spinlocks, etc: - */ -static inline unsigned long __raw_local_irq_save(void) -{ - unsigned long flags = __raw_local_save_flags(); - - raw_local_irq_disable(); - - return flags; } #define raw_local_irq_save(flags) \ =================================================================== --- a/include/asm-i386/processor.h +++ b/include/asm-i386/processor.h @@ -20,6 +20,...

...NABLE_INTERRUPTS_SYSEXIT sti; sysexit +#define INTERRUPT_RETURN iret +#define GET_CR0_INTO_EAX movl %cr0, %eax +#endif /* __ASSEMBLY__ */ +#endif /* CONFIG_PARAVIRT */ + +#ifndef __ASSEMBLY__ +#define raw_local_save_flags(flags) \ + do { (flags) = __raw_local_save_flags(); } while (0) + #define raw_local_irq_save(flags) \ do { (flags) = __raw_local_irq_save(); } while (0) +static inline int raw_irqs_disabled_flags(unsigned long flags) +{ + return !(flags & (1 << 9)); +} + +static inline int raw_irqs_disabled(void) +{ + unsigned long flags = __raw_local_save_flags(); + + return raw_irqs_disabl...

...NABLE_INTERRUPTS_SYSEXIT sti; sysexit +#define INTERRUPT_RETURN iret +#define GET_CR0_INTO_EAX movl %cr0, %eax +#endif /* __ASSEMBLY__ */ +#endif /* CONFIG_PARAVIRT */ + +#ifndef __ASSEMBLY__ +#define raw_local_save_flags(flags) \ + do { (flags) = __raw_local_save_flags(); } while (0) + #define raw_local_irq_save(flags) \ do { (flags) = __raw_local_irq_save(); } while (0) +static inline int raw_irqs_disabled_flags(unsigned long flags) +{ + return !(flags & (1 << 9)); +} + +static inline int raw_irqs_disabled(void) +{ + unsigned long flags = __raw_local_save_flags(); + + return raw_irqs_disabl...