| Message ID | PUZPR06MB62242AA2715789D100FA2E60D28D2@PUZPR06MB6224.apcprd06.prod.outlook.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] usb: gadget: u_serial: check Null pointer in EP callback | expand |
On 20-08-24 02:59 pm, 胡连勤 wrote: > From: Lianqin Hu <hulianqin@vivo.com> > > Added null pointer check to avoid system crash. Address whats becoming Null and why its happening > > Unable to handle kernel NULL pointer dereference at > virtual address 00000000000001a8 > pc : gs_read_complete+0x58/0x240 > lr : usb_gadget_giveback_request+0x40/0x160 > sp : ffffffc00f1539c0 > x29: ffffffc00f1539c0 x28: ffffff8002a30000 x27: 0000000000000000 > x26: ffffff8002a30000 x25: 0000000000000000 x24: ffffff8002a30000 > x23: ffffff8002ff9a70 x22: ffffff898e7a7b00 x21: ffffff803c9af9d8 > x20: ffffff898e7a7b00 x19: 00000000000001a8 x18: ffffffc0099fd098 > x17: 0000000000001000 x16: 0000000080000000 x15: 0000000ac1200000 > x14: 0000000000000003 x13: 000000000000d5e8 x12: 0000000355c314ac > x11: 0000000000000015 x10: 0000000000000012 x9 : 0000000000000008 > x8 : 0000000000000000 x7 : 0000000000000000 x6 : ffffff887cd12000 > x5 : 0000000000000002 x4 : ffffffc00f9b07f0 x3 : ffffffc00f1538d0 > x2 : 0000000000000001 x1 : 0000000000000000 x0 : 00000000000001a8 > 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 > el0t_64_sync_handler+0x88/0xec > el0t_64_sync+0x1b4/0x1b8 > Code: aa1f03e1 aa1303e0 52800022 2a0103e8 (88e87e62) > ---[ end trace 938847327a739172 ]--- > Kernel panic - not syncing: Oops: Fatal exception > > Signed-off-by: Lianqin Hu <hulianqin@vivo.com> > --- > v2: > - Optimize code comments > - Delete log printing > --- > drivers/usb/gadget/function/u_serial.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c > index b394105e55d6..65637d53bf02 > --- a/drivers/usb/gadget/function/u_serial.c > +++ b/drivers/usb/gadget/function/u_serial.c > @@ -454,6 +454,14 @@ static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) > { > struct gs_port *port = ep->driver_data; > > + /* When port is NULL, return to avoid panic. */ > + if (!port) > + return; > + This doesn't protect the port from going to NULL right after the above the check. Since you mentioned gser_disconnect is making port to NULL, add the serial_port_lock to protect port (just like its done on gser_disconnect/suspend/resume). Something like this would do. diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c index f975dc03a190..a33f8cd871ac 100644 --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -451,10 +451,21 @@ static void gs_rx_push(struct work_struct *work) static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) { - struct gs_port *port = ep->driver_data; + struct gs_port *port; + unsigned long flags; + + spin_lock_irqsave(&serial_port_lock, flags); + port = ep->driver_data; + + if (!port) { + spin_unlock_irqrestore(&serial_port_lock, flags); + return; + } - /* Queue all received data until the tty layer is ready for it. */ spin_lock(&port->port_lock); + spin_unlock(&serial_port_lock); + + /* Queue all received data until the tty layer is ready for it. */ list_add_tail(&req->list, &port->read_queue); schedule_delayed_work(&port->push, 0); spin_unlock(&port->port_lock); > /* Queue all received data until the tty layer is ready for it. */ > spin_lock(&port->port_lock); > list_add_tail(&req->list, &port->read_queue); > @@ -465,6 +473,14 @@ static void gs_write_complete(struct usb_ep *ep, struct usb_request *req) > { > struct gs_port *port = ep->driver_data; > > + /* When port is NULL, return to avoid panic. */ > + if (!port) > + return; > + > spin_lock(&port->port_lock); > list_add(&req->list, &port->write_pool); > port->write_started--; Same here also Best Regards, Prashanth K
Hello linux community expert: >> diff --git a/drivers/usb/gadget/function/u_serial.c >> b/drivers/usb/gadget/function/u_serial.c >> index b394105e55d6..65637d53bf02 >> --- a/drivers/usb/gadget/function/u_serial.c >> +++ b/drivers/usb/gadget/function/u_serial.c >> @@ -454,6 +454,14 @@ static void gs_read_complete(struct usb_ep *ep, >> struct usb_request *req) { >> struct gs_port *port = ep->driver_data; >> >> + /* When port is NULL, return to avoid panic. */ >> + if (!port) >> + return; >> + >This doesn't protect the port from going to NULL right after the above the check. Since you mentioned gser_disconnect is making port to NULL, add the serial_port_lock to protect port (just like its done on gser_disconnect/suspend/resume). Something like this would do. OK, it is more reasonable to modify it as follows, I will modify it again. >diff --git a/drivers/usb/gadget/function/u_serial.c >b/drivers/usb/gadget/function/u_serial.c >index f975dc03a190..a33f8cd871ac 100644 >--- a/drivers/usb/gadget/function/u_serial.c >+++ b/drivers/usb/gadget/function/u_serial.c >@@ -451,10 +451,21 @@ static void gs_rx_push(struct work_struct *work) >static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) { >- struct gs_port *port = ep->driver_data; >+ struct gs_port *port; >+ unsigned long flags; >+ >+ spin_lock_irqsave(&serial_port_lock, flags); >+ port = ep->driver_data; >+ >+ if (!port) { >+ spin_unlock_irqrestore(&serial_port_lock, flags); >+ return; >+ } >- /* Queue all received data until the tty layer is ready for it. */ > spin_lock(&port->port_lock); >+ spin_unlock(&serial_port_lock); >+ >+ /* Queue all received data until the tty layer is ready for it. >+ */ > list_add_tail(&req->list, &port->read_queue); > schedule_delayed_work(&port->push, 0); > spin_unlock(&port->port_lock); > >> /* Queue all received data until the tty layer is ready for it. */ >> spin_lock(&port->port_lock); >> list_add_tail(&req->list, &port->read_queue); @@ -465,6 +473,14 @@ >> static void gs_write_complete(struct usb_ep *ep, struct usb_request >> *req) { >> struct gs_port *port = ep->driver_data; >> >> + /* When port is NULL, return to avoid panic. */ >> + if (!port) >> + return; >> + >> spin_lock(&port->port_lock); >> list_add(&req->list, &port->write_pool); >> port->write_started--; >Same here also Thanks
On Tue, Aug 20, 2024 at 09:29:05AM +0000, 胡连勤 wrote: > From: Lianqin Hu <hulianqin@vivo.com> > > Added null pointer check to avoid system crash. > > Unable to handle kernel NULL pointer dereference at > virtual address 00000000000001a8 > pc : gs_read_complete+0x58/0x240 > lr : usb_gadget_giveback_request+0x40/0x160 > sp : ffffffc00f1539c0 > x29: ffffffc00f1539c0 x28: ffffff8002a30000 x27: 0000000000000000 > x26: ffffff8002a30000 x25: 0000000000000000 x24: ffffff8002a30000 > x23: ffffff8002ff9a70 x22: ffffff898e7a7b00 x21: ffffff803c9af9d8 > x20: ffffff898e7a7b00 x19: 00000000000001a8 x18: ffffffc0099fd098 > x17: 0000000000001000 x16: 0000000080000000 x15: 0000000ac1200000 > x14: 0000000000000003 x13: 000000000000d5e8 x12: 0000000355c314ac > x11: 0000000000000015 x10: 0000000000000012 x9 : 0000000000000008 > x8 : 0000000000000000 x7 : 0000000000000000 x6 : ffffff887cd12000 > x5 : 0000000000000002 x4 : ffffffc00f9b07f0 x3 : ffffffc00f1538d0 > x2 : 0000000000000001 x1 : 0000000000000000 x0 : 00000000000001a8 > 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 > el0t_64_sync_handler+0x88/0xec > el0t_64_sync+0x1b4/0x1b8 > Code: aa1f03e1 aa1303e0 52800022 2a0103e8 (88e87e62) > ---[ end trace 938847327a739172 ]--- > Kernel panic - not syncing: Oops: Fatal exception > > Signed-off-by: Lianqin Hu <hulianqin@vivo.com> > --- > v2: > - Optimize code comments > - Delete log printing > --- > drivers/usb/gadget/function/u_serial.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) Any specific reason you ignored my previous review comments?
diff --git a/drivers/usb/gadget/function/u_serial.c b/drivers/usb/gadget/function/u_serial.c index b394105e55d6..65637d53bf02 --- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -454,6 +454,14 @@ static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) { struct gs_port *port = ep->driver_data; + /* When port is NULL, return to avoid panic. */ + if (!port) + return; + /* Queue all received data until the tty layer is ready for it. */ spin_lock(&port->port_lock); list_add_tail(&req->list, &port->read_queue); @@ -465,6 +473,14 @@ static void gs_write_complete(struct usb_ep *ep, struct usb_request *req) { struct gs_port *port = ep->driver_data;