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Message-ID: <ef85bc4b-fbd0-f21c-1fe6-345659934bd9@hartkopp.net>
Date:   Mon, 31 Oct 2022 10:51:26 +0100
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Subject: Re: [PATCH] can: canxl: Fix unremoved canxl_packet in can_exit()
To:     Chen Zhongjin <chenzhongjin@huawei.com>,
        linux-kernel@vger.kernel.org, linux-can@vger.kernel.org,
        netdev@vger.kernel.org
Cc:     mkl@pengutronix.de, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com, mailhol.vincent@wanadoo.fr
References: <20221031033053.37849-1-chenzhongjin@huawei.com>
Content-Language: en-US
From:   Oliver Hartkopp <socketcan@hartkopp.net>
In-Reply-To: <20221031033053.37849-1-chenzhongjin@huawei.com>
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On 31.10.22 04:30, Chen Zhongjin wrote:
> In can_init(), dev_add_pack(&canxl_packet) is added but not removed in
> can_exit(). It break the packet handler list and can make kernel panic
> when can_init() for the second time.
> 
>> modprobe can && rmmod can
>> rmmod xxx && modprobe can
> 
> BUG: unable to handle page fault for address: fffffbfff807d7f4
> RIP: 0010:dev_add_pack+0x133/0x1f0
> Call Trace:
>   <TASK>
>   can_init+0xaa/0x1000 [can]
>   do_one_initcall+0xd3/0x4e0
>   ...
> 
> Fixes: fb08cba12b52 ("can: canxl: update CAN infrastructure for CAN XL frames")
> Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>

Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>

Thanks for the finding!

Best regards,
Oliver

> ---
>   net/can/af_can.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/net/can/af_can.c b/net/can/af_can.c
> index 9503ab10f9b8..5e9e3e1e9825 100644
> --- a/net/can/af_can.c
> +++ b/net/can/af_can.c
> @@ -902,6 +902,7 @@ static __init int can_init(void)
>   static __exit void can_exit(void)
>   {
>   	/* protocol unregister */
> +	dev_remove_pack(&canxl_packet);
>   	dev_remove_pack(&canfd_packet);
>   	dev_remove_pack(&can_packet);
>   	sock_unregister(PF_CAN);