From: Michael Tretter <m.tretter@pengutronix.de>
To: Nadezda Lutovinova <lutovinova@ispras.ru>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
ldv-project@linuxtesting.org
Subject: Re: [PATCH] media: allegro: request irq after initializing mbox_status
Date: Mon, 23 Aug 2021 09:53:53 +0200 [thread overview]
Message-ID: <20210823075353.GC28846@pengutronix.de> (raw)
In-Reply-To: <20210819154935.19826-1-lutovinova@ispras.ru>
Hi Nadezda,
On Thu, 19 Aug 2021 18:49:35 +0300, Nadezda Lutovinova wrote:
> If IRQ occurs between calling devm_request_threaded_irq() and
> allegro_firmware_request_nowait(), then null pointer dereference
> occurs since dev->mbox_status wasn't initialized yet but used
> in allegro_mbox_notify().
Thanks for the patch. As explained in [0], this is not an issue.
>
> The patch puts registration of the interrupt handler after
> initializing of neccesery data.
The interrupt handler must be registered during the execution of
allegro_fw_callback(), because the driver exchanges messages with the firmware
during the bring up. With this patch this is not guaranteed anymore.
Michael
[0] https://lore.kernel.org/linux-media/20210511072834.GC17882@pengutronix.de/
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Nadezda Lutovinova <lutovinova@ispras.ru>
> ---
> .../media/platform/allegro-dvt/allegro-core.c | 24 +++++++++----------
> 1 file changed, 12 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/media/platform/allegro-dvt/allegro-core.c b/drivers/media/platform/allegro-dvt/allegro-core.c
> index 887b492e4ad1..9c1997ff74e8 100644
> --- a/drivers/media/platform/allegro-dvt/allegro-core.c
> +++ b/drivers/media/platform/allegro-dvt/allegro-core.c
> @@ -3707,18 +3707,6 @@ static int allegro_probe(struct platform_device *pdev)
> return PTR_ERR(dev->sram);
> }
>
> - irq = platform_get_irq(pdev, 0);
> - if (irq < 0)
> - return irq;
> - ret = devm_request_threaded_irq(&pdev->dev, irq,
> - allegro_hardirq,
> - allegro_irq_thread,
> - IRQF_SHARED, dev_name(&pdev->dev), dev);
> - if (ret < 0) {
> - dev_err(&pdev->dev, "failed to request irq: %d\n", ret);
> - return ret;
> - }
> -
> ret = v4l2_device_register(&pdev->dev, &dev->v4l2_dev);
> if (ret)
> return ret;
> @@ -3732,6 +3720,18 @@ static int allegro_probe(struct platform_device *pdev)
> return ret;
> }
>
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0)
> + return irq;
> + ret = devm_request_threaded_irq(&pdev->dev, irq,
> + allegro_hardirq,
> + allegro_irq_thread,
> + IRQF_SHARED, dev_name(&pdev->dev), dev);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to request irq: %d\n", ret);
> + return ret;
> + }
> +
> return 0;
> }
>
> --
> 2.17.1
>
>
prev parent reply other threads:[~2021-08-23 7:54 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-19 15:49 [PATCH] media: allegro: request irq after initializing mbox_status Nadezda Lutovinova
2021-08-23 7:53 ` Michael Tretter [this message]
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