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Subject: Re: [PATCH] um: vector: Use GFP_ATOMIC under spin lock
To:     Tiezhu Yang <yangtiezhu@loongson.cn>,
        Jeff Dike <jdike@addtoit.com>,
        Richard Weinberger <richard@nod.at>
Cc:     linux-um@lists.infradead.org, linux-kernel@vger.kernel.org,
        Xuefeng Li <lixuefeng@loongson.cn>
References: <1592544007-2751-1-git-send-email-yangtiezhu@loongson.cn>
From:   Anton Ivanov <anton.ivanov@cambridgegreys.com>
Message-ID: <04be37fc-c8cb-f506-20a5-97467b638069@cambridgegreys.com>
Date:   Mon, 21 Sep 2020 15:36:38 +0100
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On 19/06/2020 06:20, Tiezhu Yang wrote:
> Use GFP_ATOMIC instead of GFP_KERNEL under spin lock to fix possible
> sleep-in-atomic-context bugs.
> 
> Fixes: 9807019a62dc ("um: Loadable BPF "Firmware" for vector drivers")
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>   arch/um/drivers/vector_kern.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/um/drivers/vector_kern.c b/arch/um/drivers/vector_kern.c
> index 8735c46..555203e 100644
> --- a/arch/um/drivers/vector_kern.c
> +++ b/arch/um/drivers/vector_kern.c
> @@ -1403,7 +1403,7 @@ static int vector_net_load_bpf_flash(struct net_device *dev,
>   		kfree(vp->bpf->filter);
>   		vp->bpf->filter = NULL;
>   	} else {
> -		vp->bpf = kmalloc(sizeof(struct sock_fprog), GFP_KERNEL);
> +		vp->bpf = kmalloc(sizeof(struct sock_fprog), GFP_ATOMIC);
>   		if (vp->bpf == NULL) {
>   			netdev_err(dev, "failed to allocate memory for firmware\n");
>   			goto flash_fail;
> @@ -1415,7 +1415,7 @@ static int vector_net_load_bpf_flash(struct net_device *dev,
>   	if (request_firmware(&fw, efl->data, &vdevice->pdev.dev))
>   		goto flash_fail;
>   
> -	vp->bpf->filter = kmemdup(fw->data, fw->size, GFP_KERNEL);
> +	vp->bpf->filter = kmemdup(fw->data, fw->size, GFP_ATOMIC);
>   	if (!vp->bpf->filter)
>   		goto free_buffer;
>   
> 
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
-- 
Anton R. Ivanov
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