Re: [PATCH v2] usb: gadget: u_serial: Disable ep before setting port to null to fix the crash caused by port being null

["gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>]

On Mon, Dec 16, 2024 at 12:31:45PM +0000, 胡连勤 wrote:
> From: Lianqin Hu <hulianqin@vivo.com>
> 
> Considering that in some extreme cases, when performing the
> unbinding operation, gserial_disconnect has cleared gser->ioport,
> which triggers gadget reconfiguration, and then calls gs_read_complete,
> resulting in access to a null pointer. Therefore, ep is disabled before
> gserial_disconnect sets port to null to prevent this from happening.
> 
> Call trace:
>  gs_read_complete+0x58/0x240
>  usb_gadget_giveback_request+0x40/0x160
>  dwc3_remove_requests+0x170/0x484
>  dwc3_ep0_out_start+0xb0/0x1d4
>  __dwc3_gadget_start+0x25c/0x720
>  kretprobe_trampoline.cfi_jt+0x0/0x8
>  kretprobe_trampoline.cfi_jt+0x0/0x8
>  udc_bind_to_driver+0x1d8/0x300
>  usb_gadget_probe_driver+0xa8/0x1dc
>  gadget_dev_desc_UDC_store+0x13c/0x188
>  configfs_write_iter+0x160/0x1f4
>  vfs_write+0x2d0/0x40c
>  ksys_write+0x7c/0xf0
>  __arm64_sys_write+0x20/0x30
>  invoke_syscall+0x60/0x150
>  el0_svc_common+0x8c/0xf8
>  do_el0_svc+0x28/0xa0
>  el0_svc+0x24/0x84
> 
> Fixes: c1dca562be8a ("usb gadget: split out serial core")
> Cc: stable@vger.kernel.org
> 
> Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Lianqin Hu <hulianqin@vivo.com>
> 
> v2:
>  - Remove some address information from patch descriptions
>  - Link to v1: https://lore.kernel.org/all/TYUPR06MB621763AB815989161F4033AFD2762@TYUPR06MB6217.apcprd06.prod.outlook.com/
>  - Link to suggestions: https://lore.kernel.org/all/TYUPR06MB6217DE28012FFEC5E808DD64D2962@TYUPR06MB6217.apcprd06.prod.outlook.com/

The "v2:" needs to go below the --- line, what happened to that?

And no need to have a blank line after the cc: stable, right?  Did you
run checkpatch.pl on this?

thanks,

greg k-h