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Date:   Thu, 10 Jun 2021 09:06:19 +0100
Message-ID: <87k0n2qh38.wl-maz@kernel.org>
From:   Marc Zyngier <maz@kernel.org>
To:     Heiner Kallweit <hkallweit1@gmail.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
        Christoph Hellwig <hch@lst.de>
Subject: Re: linux-next: NVME using PCI legacy interrupts only
In-Reply-To: <52371274-20bc-a150-a3ed-ba3e1305ad3e@gmail.com>
References: <52371274-20bc-a150-a3ed-ba3e1305ad3e@gmail.com>
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On Wed, 09 Jun 2021 19:43:57 +0100,
Heiner Kallweit <hkallweit1@gmail.com> wrote:
> 
> I found that on linux-next from June 8th my nvme disk is using legacy
> interrupts only. Some debugging lead me to irq_find_mapping() in
> msi_domain_alloc() returning -EEXIST.
> 
> The nvme core first allocates a MSI-X interrupt for setup purposes
> and later frees it and allocates the final number of MSI-X interrupts.
> 
> The following experimental change brought back the MSI-X interrupts.
> This makes me think that somehow freeing a MSI-X interrupt doesn't
> free it completely. I didn't see this behavior a few days ago,
> therefore I think it's related to the recent changes to
> irqdomain/genirq.
> 
> Didn't do a bisect yet, maybe you have an idea already.

Yeah, recent changes in the irqdomain subsystem seem to have uncovered
a long standing issue where we are leaving dangling references in some
domains....

I've now dropped the branch from -next while I figure it out.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.