On Mon, Nov 07, 2022 at 08:56:06AM +0000, Jiantao Zhang wrote: > This reverts commit 0a55187a1ec8c Please show the full hash for this line. > > In the process of switching USB config from rndis to other config, if function gadget->ops->pullup() return an error,it will inevitably cause a CFI failure(Linux version 5.10.43). Please wrap the line properly. And CFI is not in 5.10, so why is this an issue? > > analysis as follows: > ====================================================== > (1) write /config/usb_gadget/g1/UDC "none" (init.usb.configfs.rc:2) > > gether_disconnect+0x2c/0x1f8 (dev->port_usb = NULL) > rndis_disable+0x4c/0x74 > composite_disconnect+0x74/0xb0 > configfs_composite_disconnect+0x60/0x7c > usb_gadget_disconnect+0x70/0x124 > usb_gadget_unregister_driver+0xc8/0x1d8 > gadget_dev_desc_UDC_store+0xec/0x1e4 > > in function usb_gadget_disconnect(),gadget->udc->driver->disconnect() > will not be called when gadget->ops->pullup() return an error, therefore, pointer dev->port will not be set to NULL. > > (2) rm /config/usb_gadget/g1/configs/b.1/f1 (init.usb.configfs.rc:8) > (f1 -> ../../../../usb_gadget/g1/functions/rndis.gs4) > > rndis_deregister+0x28/0x54 > rndis_free+0x44/0x7c > usb_put_function+0x14/0x1c > config_usb_cfg_unlink+0xc4/0xe0 > configfs_unlink+0x124/0x1c8 > vfs_unlink+0x114/0x1dc > > (3) rmdir /config/usb_gadget/g1/functions/rndis.gs4 > (init.usb.configfs.rc:11) > > CFI failure (target: [<ffffff814bc20c00>] 0000000068f50078): > CPU: 2 PID: 1 Comm: init VIP: 00 Tainted: G W O 5.10.43 #1 > Call trace: > __cfi_slowpath+0x300/0x3bc > rndis_signal_disconnect+0x1e0/0x204 > rndis_close+0x24/0x2c > eth_stop+0xd0/0x234 (if dev->port_usb != NULL, call rndis_close) > __dev_close_many+0x204/0x2d4 > dev_close_many+0x48/0x2c8 > rollback_registered_many+0x184/0xdac > unregister_netdevice_queue+0xf8/0x24c > rndis_free_inst+0x78/0xc8 > rndis_attr_release+0x3c/0x84 > config_item_release+0x6c/0x180 > configfs_rmdir+0x7e0/0xca0 > > Since the rndis memory has been freed in step2, function rndis_close cannot be called here. In function eth_stop(), if pointer dev->port_usb is NULL, function rndis_close() will not be called. So, if > gadget->ops->pullup() return an error in step1, a CFI failure will be > caused here. > ====================================================== > Through above analysis, i think gadget->udc->driver->disconnect() need to be called even if gadget->udc->driver->disconnect() return an error. I really do not understand, sorry. What does CFI have to do with anything here? What functions are mis-matched that CFI trips over it? And by reverting this change, don't you now have the original problem that this commit was trying to solve? > > Signed-off-by: Jiantao Zhang <water.zhangjiantao@xxxxxxxxxx> > Signed-off-by: TaoXue <xuetao09@xxxxxxxxxx> No Fixes: tag? No cc: stable? thanks, greg k-h
