From: Peter Zijlstra <peterz@infradead.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: linux-arch@vger.kernel.org, Alexey Kardashevskiy <aik@ozlabs.ru>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>
Subject: Re: [PATCH 1/2] lockdep: improve current->(hard|soft)irqs_enabled synchronisation with actual irq state
Date: Thu, 23 Jul 2020 13:40:10 +0200 [thread overview]
Message-ID: <20200723114010.GO5523@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20200723105615.1268126-1-npiggin@gmail.com>
On Thu, Jul 23, 2020 at 08:56:14PM +1000, Nicholas Piggin wrote:
> diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
> index 3a0db7b0b46e..35060be09073 100644
> --- a/arch/powerpc/include/asm/hw_irq.h
> +++ b/arch/powerpc/include/asm/hw_irq.h
> @@ -200,17 +200,14 @@ static inline bool arch_irqs_disabled(void)
> #define powerpc_local_irq_pmu_save(flags) \
> do { \
> raw_local_irq_pmu_save(flags); \
> - trace_hardirqs_off(); \
> + if (!raw_irqs_disabled_flags(flags)) \
> + trace_hardirqs_off(); \
> } while(0)
> #define powerpc_local_irq_pmu_restore(flags) \
> do { \
> - if (raw_irqs_disabled_flags(flags)) { \
> - raw_local_irq_pmu_restore(flags); \
> - trace_hardirqs_off(); \
> - } else { \
> + if (!raw_irqs_disabled_flags(flags)) \
> trace_hardirqs_on(); \
> - raw_local_irq_pmu_restore(flags); \
> - } \
> + raw_local_irq_pmu_restore(flags); \
> } while(0)
You shouldn't be calling lockdep from NMI context! That is, I recently
added suport for that on x86:
https://lkml.kernel.org/r/20200623083721.155449112@infradead.org
https://lkml.kernel.org/r/20200623083721.216740948@infradead.org
But you need to be very careful on how you order things, as you can see
the above relies on preempt_count() already having been incremented with
NMI_MASK.
next prev parent reply other threads:[~2020-07-23 11:43 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-23 10:56 [PATCH 1/2] lockdep: improve current->(hard|soft)irqs_enabled synchronisation with actual irq state Nicholas Piggin
2020-07-23 10:56 ` [PATCH 2/2] lockdep: warn on redundant or incorrect irq state changes Nicholas Piggin
2020-07-24 2:57 ` kernel test robot
2020-08-04 10:00 ` Alexey Kardashevskiy
2020-07-23 11:40 ` Peter Zijlstra [this message]
2020-07-23 13:11 ` [PATCH 1/2] lockdep: improve current->(hard|soft)irqs_enabled synchronisation with actual irq state Nicholas Piggin
2020-07-23 14:59 ` Peter Zijlstra
2020-07-23 16:20 ` Nicholas Piggin
2020-07-24 4:16 ` Alexey Kardashevskiy
2020-07-24 5:59 ` Nicholas Piggin
2020-07-26 7:40 ` Alexey Kardashevskiy
2020-07-24 6:16 ` Athira Rajeev
2020-07-24 2:19 ` kernel test robot
2020-07-24 3:15 ` kernel test robot
2020-07-25 20:26 ` Peter Zijlstra
2020-07-26 4:14 ` Nicholas Piggin
2020-07-26 11:59 ` peterz
2020-07-26 12:11 ` peterz
2020-07-28 11:22 ` Nicholas Piggin
2020-08-07 11:11 ` peterz
2020-08-12 8:18 ` Nicholas Piggin
2020-08-12 10:35 ` peterz
2020-08-18 7:22 ` Nicholas Piggin
2020-08-18 15:41 ` peterz
2020-08-18 23:54 ` Nicholas Piggin
2020-08-19 10:39 ` Alexey Kardashevskiy
2020-08-19 15:32 ` peterz
2020-08-19 15:39 ` peterz
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