Commit f33eee1e authored by Lianqin Hu's avatar Lianqin Hu Committed by Wen Zhiwei
Browse files

usb: gadget: u_serial: Disable ep before setting port to null to fix the crash... 

usb: gadget: u_serial: Disable ep before setting port to null to fix the crash caused by port being null

stable inclusion
from stable-v6.6.72
commit 0c50f00cc29948184af05bda31392fff5821f4f3
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IBQN9L

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0c50f00cc29948184af05bda31392fff5821f4f3



--------------------------------

commit 13014969cbf07f18d62ceea40bd8ca8ec9d36cec upstream.

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: c1dca562 ("usb gadget: split out serial core")
Cc: stable <stable@kernel.org>
Suggested-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarLianqin Hu <hulianqin@vivo.com>
Link: https://lore.kernel.org/r/TYUPR06MB621733B5AC690DBDF80A0DCCD2042@TYUPR06MB6217.apcprd06.prod.outlook.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarWen Zhiwei <wenzhiwei@kylinos.cn>
parent cf28f3f4

drivers/usb/gadget/function/u_serial.c

+4 −4
Original line number Diff line number Diff line
@@ -1398,6 +1398,10 @@ void gserial_disconnect(struct gserial *gser) 
	/* REVISIT as above: how best to track this? */

	port->port_line_coding = gser->port_line_coding;



	/* disable endpoints, aborting down any active I/O */

	usb_ep_disable(gser->out);

	usb_ep_disable(gser->in);



	port->port_usb = NULL;

	gser->ioport = NULL;

	if (port->port.count > 0) {
@@ -1409,10 +1413,6 @@ void gserial_disconnect(struct gserial *gser) 
	spin_unlock(&port->port_lock);

	spin_unlock_irqrestore(&serial_port_lock, flags);



	/* disable endpoints, aborting down any active I/O */

	usb_ep_disable(gser->out);

	usb_ep_disable(gser->in);



	/* finally, free any unused/unusable I/O buffers */

	spin_lock_irqsave(&port->port_lock, flags);

	if (port->port.count == 0)