5.4-stable review patch. If anyone has any objections, please let me know.
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From: Lianqin Hu hulianqin@vivo.com
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: c1dca562be8a ("usb gadget: split out serial core") Cc: stable stable@kernel.org Suggested-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Lianqin Hu hulianqin@vivo.com Link: https://lore.kernel.org/r/TYUPR06MB621733B5AC690DBDF80A0DCCD2042@TYUPR06MB62... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/gadget/function/u_serial.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/drivers/usb/gadget/function/u_serial.c +++ b/drivers/usb/gadget/function/u_serial.c @@ -1369,6 +1369,10 @@ void gserial_disconnect(struct gserial * /* 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 || port->openclose) { @@ -1378,10 +1382,6 @@ void gserial_disconnect(struct gserial * } spin_unlock_irqrestore(&port->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 && !port->openclose)