Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.33 as permitted sender) client-ip=23.128.96.33;
Date:   Wed, 1 Nov 2023 08:29:57 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Xingxing Luo <xingxing.luo@unisoc.com>
Cc:     b-liu@ti.com, keescook@chromium.org, nathan@kernel.org,
        ndesaulniers@google.com, trix@redhat.com,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org, llvm@lists.linux.dev,
        xingxing0070.luo@gmail.com, Zhiyong.Liu@unisoc.com,
        Cixi.Geng1@unisoc.com, Orson.Zhai@unisoc.com, zhang.lyra@gmail.com
Subject: Re: [PATCH V2] usb: musb: Check requset->buf before use to avoid
 crash issue
Message-ID: <2023110144-sequence-twistable-3580@gregkh>
References: <20231101071421.29462-1-xingxing.luo@unisoc.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20231101071421.29462-1-xingxing.luo@unisoc.com>
Precedence: bulk

On Wed, Nov 01, 2023 at 03:14:21PM +0800, Xingxing Luo wrote:
> When connecting USB to PC, there is a very low probability of kernel
> crash. The reason is that in ep0_txstate(), the buf member of struct
> usb_request used may be a null pointer. Therefore, it needs to
> determine whether it is null before using it.
> 
> [ 4888.071462][T597@C0] Call trace:
> [ 4888.071467][T597@C0]  musb_default_write_fifo+0xa0/0x1ac [musb_hdrc]
> [ 4888.087190][T597@C0]  musb_write_fifo+0x3c/0x90 [musb_hdrc]
> [ 4888.099826][T597@C0]  ep0_txstate+0x78/0x218 [musb_hdrc]
> [ 4888.153918][T597@C0]  musb_g_ep0_irq+0x3c4/0xe10 [musb_hdrc]
> [ 4888.159663][T597@C0]  musb_interrupt+0xab4/0xf1c [musb_hdrc]
> [ 4888.165391][T597@C0]  sprd_musb_interrupt+0x1e4/0x484 [musb_sprd]
> [ 4888.171447][T597@C0]  __handle_irq_event_percpu+0xd8/0x2f8
> [ 4888.176901][T597@C0]  handle_irq_event+0x70/0xe4
> [ 4888.181487][T597@C0]  handle_fasteoi_irq+0x15c/0x230
> [ 4888.186420][T597@C0]  handle_domain_irq+0x88/0xfc
> [ 4888.191090][T597@C0]  gic_handle_irq+0x60/0x138
> [ 4888.195591][T597@C0]  call_on_irq_stack+0x40/0x70
> [ 4888.200263][T597@C0]  do_interrupt_handler+0x50/0xac
> [ 4888.205196][T597@C0]  el1_interrupt+0x34/0x64
> [ 4888.209524][T597@C0]  el1h_64_irq_handler+0x1c/0x2c
> [ 4888.214370][T597@C0]  el1h_64_irq+0x7c/0x80
> [ 4888.218525][T597@C0]  __check_heap_object+0x1ac/0x1fc
> [ 4888.223544][T597@C0]  __check_object_size+0x10c/0x20c
> [ 4888.228563][T597@C0]  simple_copy_to_iter+0x40/0x74
> [ 4888.233410][T597@C0]  __skb_datagram_iter+0xa0/0x310
> [ 4888.238343][T597@C0]  skb_copy_datagram_iter+0x44/0x110
> [ 4888.243535][T597@C0]  netlink_recvmsg+0xdc/0x364
> [ 4888.248123][T597@C0]  ____sys_recvmsg.llvm.16749613423860851707+0x358/0x6c0
> [ 4888.255045][T597@C0]  ___sys_recvmsg+0xe0/0x1dc
> [ 4888.259544][T597@C0]  __arm64_sys_recvmsg+0xc4/0x10c
> [ 4888.264478][T597@C0]  invoke_syscall+0x6c/0x15c
> [ 4888.268976][T597@C0]  el0_svc_common.llvm.12373701176611417606+0xd4/0x120
> [ 4888.275726][T597@C0]  do_el0_svc+0x34/0xac
> [ 4888.279795][T597@C0]  el0_svc+0x28/0x90
> [ 4888.283603][T597@C0]  el0t_64_sync_handler+0x88/0xec
> [ 4888.288548][T597@C0]  el0t_64_sync+0x1b4/0x1b8
> [ 4888.292956][T597@C0] Code: 540002c3 53027ea8 aa1303e9 71000508 (b840452a)
> [ 4888.299789][T597@C0] ---[ end trace 14a301b7253e83cc ]---
> 
> Fixes: 550a7375fe72 ("USB: Add MUSB and TUSB support")
> Signed-off-by: Xingxing Luo <xingxing.luo@unisoc.com>
> ---
> v1 -> v2: - Fixed a spelling error
>           - Add the fixed commit id
> 
>  drivers/usb/musb/musb_gadget_ep0.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/usb/musb/musb_gadget_ep0.c b/drivers/usb/musb/musb_gadget_ep0.c
> index 6d7336727388..19eb7a5e1fdc 100644
> --- a/drivers/usb/musb/musb_gadget_ep0.c
> +++ b/drivers/usb/musb/musb_gadget_ep0.c
> @@ -531,6 +531,11 @@ static void ep0_txstate(struct musb *musb)
>  
>  	request = &req->request;
>  
> +	if (!request->buf) {
> +		musb_dbg(musb, "request->buf is NULL");
> +		return;
> +	}
> +
>  	/* load the data */
>  	fifo_src = (u8 *) request->buf + request->actual;
>  	fifo_count = min((unsigned) MUSB_EP0_FIFOSIZE,
> -- 
> 2.17.1
> 
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- You have marked a patch with a "Fixes:" tag for a commit that is in an
  older released kernel, yet you do not have a cc: stable line in the
  signed-off-by area at all, which means that the patch will not be
  applied to any older kernel releases.  To properly fix this, please
  follow the documented rules in the
  Documentation/process/stable-kernel-rules.rst file for how to resolve
  this.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
from other developers.

thanks,

greg k-h's patch email bot