From 33a06f1300a79cfd461cea0268f05e969d4f34ec Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Thu, 16 Jul 2020 14:09:48 +0200 Subject: [PATCH] usb: dwc2: Fix error path in gadget registration When gadget registration fails, one should not call usb_del_gadget_udc(). Ensure this by setting gadget->udc to NULL. Also in case of a failure there is no need to disable low-level hardware, so return immiedetly instead of jumping to error_init label. This fixes the following kernel NULL ptr dereference on gadget failure (can be easily triggered with g_mass_storage without any module parameters): dwc2 12480000.hsotg: dwc2_check_params: Invalid parameter besl=1 dwc2 12480000.hsotg: dwc2_check_params: Invalid parameter g_np_tx_fifo_size=1024 dwc2 12480000.hsotg: EPs: 16, dedicated fifos, 7808 entries in SPRAM Mass Storage Function, version: 2009/09/11 LUN: removable file: (no medium) no file given for LUN0 g_mass_storage 12480000.hsotg: failed to start g_mass_storage: -22 8<--- cut here --- Unable to handle kernel NULL pointer dereference at virtual address 00000104 pgd = (ptrval) [00000104] *pgd=00000000 Internal error: Oops: 805 [#1] PREEMPT SMP ARM Modules linked in: CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.8.0-rc5 #3133 Hardware name: Samsung Exynos (Flattened Device Tree) Workqueue: events deferred_probe_work_func PC is at usb_del_gadget_udc+0x38/0xc4 LR is at __mutex_lock+0x31c/0xb18 ... Process kworker/0:1 (pid: 12, stack limit = 0x(ptrval)) Stack: (0xef121db0 to 0xef122000) ... [] (usb_del_gadget_udc) from [] (dwc2_hsotg_remove+0x10/0x20) [] (dwc2_hsotg_remove) from [] (dwc2_driver_probe+0x57c/0x69c) [] (dwc2_driver_probe) from [] (platform_drv_probe+0x6c/0xa4) [] (platform_drv_probe) from [] (really_probe+0x200/0x48c) [] (really_probe) from [] (driver_probe_device+0x78/0x1fc) [] (driver_probe_device) from [] (bus_for_each_drv+0x74/0xb8) [] (bus_for_each_drv) from [] (__device_attach+0xd4/0x16c) [] (__device_attach) from [] (bus_probe_device+0x88/0x90) [] (bus_probe_device) from [] (deferred_probe_work_func+0x3c/0xd0) [] (deferred_probe_work_func) from [] (process_one_work+0x234/0x7dc) [] (process_one_work) from [] (worker_thread+0x44/0x51c) [] (worker_thread) from [] (kthread+0x158/0x1a0) [] (kthread) from [] (ret_from_fork+0x14/0x20) Exception stack(0xef121fb0 to 0xef121ff8) ... ---[ end trace 9724c2fc7cc9c982 ]--- While fixing this also fix the double call to dwc2_lowlevel_hw_disable() if dr_mode is set to USB_DR_MODE_PERIPHERAL. In such case low-level hardware is already disabled before calling usb_add_gadget_udc(). That function correctly preserves low-level hardware state, there is no need for the second unconditional dwc2_lowlevel_hw_disable() call. Fixes: 207324a321a8 ("usb: dwc2: Postponed gadget registration to the udc class driver") Acked-by: Minas Harutyunyan Signed-off-by: Marek Szyprowski Signed-off-by: Felipe Balbi --- drivers/usb/dwc2/platform.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c index 8fea5f1..68b56b4 100644 --- a/drivers/usb/dwc2/platform.c +++ b/drivers/usb/dwc2/platform.c @@ -591,6 +591,7 @@ static int dwc2_driver_probe(struct platform_device *dev) if (hsotg->gadget_enabled) { retval = usb_add_gadget_udc(hsotg->dev, &hsotg->gadget); if (retval) { + hsotg->gadget.udc = NULL; dwc2_hsotg_remove(hsotg); goto error_init; } @@ -602,7 +603,8 @@ error_init: if (hsotg->params.activate_stm_id_vb_detection) regulator_disable(hsotg->usb33d); error: - dwc2_lowlevel_hw_disable(hsotg); + if (hsotg->dr_mode != USB_DR_MODE_PERIPHERAL) + dwc2_lowlevel_hw_disable(hsotg); return retval; } -- 2.7.4