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Message-ID: <71004ab9-38e0-4323-2506-38d6e71130f6@huawei.com>
Date:   Thu, 16 Jun 2022 15:11:12 +0800
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Subject: Re: [PATCH -next] driver core: fix deadlock in __driver_attach
To:     <gregkh@linuxfoundation.org>, <rafael@kernel.org>
CC:     <linux-kernel@vger.kernel.org>, <yukuai3@huawei.com>
References: <20220608094355.3298420-1-zhangwensheng5@huawei.com>
From:   "zhangwensheng (E)" <zhangwensheng5@huawei.com>
In-Reply-To: <20220608094355.3298420-1-zhangwensheng5@huawei.com>
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friendly ping...

在 2022/6/8 17:43, Zhang Wensheng 写道:
> In __driver_attach function, There are also potential AA deadlock
> problem, like the commit b232b02bf3c2 ("driver core: fix deadlock
> in __device_attach").
>
> Fixes: ef0ff68351be ("driver core: Probe devices asynchronously instead of the driver")
> Signed-off-by: Zhang Wensheng <zhangwensheng5@huawei.com>
> ---
>   drivers/base/dd.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index 11b0fb6414d3..b766968a873c 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -1115,6 +1115,7 @@ static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie)
>   static int __driver_attach(struct device *dev, void *data)
>   {
>   	struct device_driver *drv = data;
> +	bool async = false;
>   	int ret;
>   
>   	/*
> @@ -1153,9 +1154,11 @@ static int __driver_attach(struct device *dev, void *data)
>   		if (!dev->driver && !dev->p->async_driver) {
>   			get_device(dev);
>   			dev->p->async_driver = drv;
> -			async_schedule_dev(__driver_attach_async_helper, dev);
> +			async = true;
>   		}
>   		device_unlock(dev);
> +		if (async)
> +			async_schedule_dev(__driver_attach_async_helper, dev);
>   		return 0;
>   	}
>