From: Philippe Gerum <rpm@xenomai.org>
To: Florian Bezdeka <florian.bezdeka@siemens.com>
Cc: xenomai@lists.linux.dev
Subject: Re: [PATCH RFC Dovetail 6.16 5/5] kernel/irq/chip: Do not call low level irq chip hooks directly
Date: Tue, 30 Sep 2025 09:52:36 +0200 [thread overview]
Message-ID: <874iskxtq3.fsf@xenomai.org> (raw)
In-Reply-To: <689eb39d04f64799e522453da752d0c367217b62.camel@siemens.com> (Florian Bezdeka's message of "Mon, 29 Sep 2025 23:15:00 +0200")
Florian Bezdeka <florian.bezdeka@siemens.com> writes:
> On Sun, 2025-09-28 at 10:12 +0200, Philippe Gerum wrote:
>> Florian Bezdeka <florian.bezdeka@siemens.com> writes:
>>
>> > irq_mask() and irq_unmask() are tracking a software IRQ state that
>> > might run out of sync when bypassing them.
>> >
>> > No functional change.
>> >
>>
>> Actually, there is. Percpu IRQs are not serialized by the desc->lock, so
>> calling mask_irq/unmask_irq in these handlers is unsafe since we may end
>> up flipping bits from the irqd state concurrently on multiple CPUs for
>> the same descriptor. This is the reason why masking/unmasking was
>> open-coded there. This patch typically breaks my kvm/arm64 fixture at
>> boot, not observed on kvm/x86 so far though.
>>
>
> I clearly missed the serialization part. Wondering why this did not
> trigger on any board / kvm test...
>
> Anyway, it's clear that this patch should be dropped.
>
> Do you want me to resend the series with 5/5 dropped?
>
No need for this. I'll pick the rest of the series directly. Thanks.
--
Philippe.
next prev parent reply other threads:[~2025-09-30 7:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-25 13:05 [PATCH RFC Dovetail 6.16 0/5] Dovetail: Minor cleanups found while debugging the pipeline entry code Florian Bezdeka
2025-09-25 13:05 ` [PATCH RFC Dovetail 6.16 1/5] kernel/entry: irq_pipeline: Do not leave .noinstr.text section Florian Bezdeka
2025-09-26 8:49 ` Philippe Gerum
2025-09-26 10:26 ` Florian Bezdeka
2025-09-26 10:37 ` Philippe Gerum
2025-09-25 13:05 ` [PATCH RFC Dovetail 6.16 2/5] kernel/irq/chip: Change return value of get_flow_step() to int Florian Bezdeka
2025-09-25 13:05 ` [PATCH RFC Dovetail 6.16 3/5] kernel/irq/chip: Simplify may_start_flow() Florian Bezdeka
2025-09-26 8:50 ` Philippe Gerum
2025-09-25 13:05 ` [PATCH RFC Dovetail 6.16 4/5] kernel/irq/chip: Simplify should_feed_pipeline() Florian Bezdeka
2025-09-25 13:05 ` [PATCH RFC Dovetail 6.16 5/5] kernel/irq/chip: Do not call low level irq chip hooks directly Florian Bezdeka
2025-09-28 8:12 ` Philippe Gerum
2025-09-28 8:21 ` Philippe Gerum
2025-09-29 21:15 ` Florian Bezdeka
2025-09-30 7:52 ` Philippe Gerum [this message]
2025-09-28 12:25 ` [PATCH RFC Dovetail 6.16 0/5] Dovetail: Minor cleanups found while debugging the pipeline entry code Philippe Gerum
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