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Date:   Thu, 19 Jan 2023 09:48:56 -0700
From:   Keith Busch <kbusch@kernel.org>
To:     Christoph Hellwig <hch@lst.de>
Cc:     Klaus Jensen <its@irrelevant.dk>, Jens Axboe <axboe@fb.com>,
        Sagi Grimberg <sagi@grimberg.me>,
        linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>
Subject: Re: regression on aarch64? panic on boot
Message-ID: <Y8l0ePagRXDHQByr@kbusch-mbp>
References: <Y8XINx8fpGPKudW6@cormorant.local>
 <20230117055819.GB13795@lst.de>
 <Y8ZA30EoAFaFPwVC@cormorant.local>
 <20230117063735.GA14468@lst.de>
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On Tue, Jan 17, 2023 at 07:37:35AM +0100, Christoph Hellwig wrote:
> On Tue, Jan 17, 2023 at 07:31:59AM +0100, Klaus Jensen wrote:
> > Good morning Christoph,
> > 
> > Yep, the above works.
> 
> Context for the newly added: This is dropping the newly added
> PROBE_PREFER_ASYNCHRONOUS in nvme, which causes Klaus' arm64 (but not
> other boot tests) to fail.  Any idea what could be going wrong there
> probably in userspace?

Prior to 6.2, the driver would do it's own async_schedule, and that
async probe function would flush the first scan work.
wait_for_device_probe() was then forced to wait for the scan_work to
complete, which brings up the root device.

We're not flushing the scan_work anymore from our probe, so this should
fix it for 6.2:

---
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index b294b41a149a7..ff97426749976 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -3046,6 +3046,7 @@ static int nvme_probe(struct pci_dev *pdev, const struct pci_device_id *id)

        nvme_start_ctrl(&dev->ctrl);
        nvme_put_ctrl(&dev->ctrl);
+       flush_work(&dev->ctrl.scan_work);
        return 0;

 out_disable:
--