From: Marek Szyprowski m.szyprowski@samsung.com
[ Upstream commit 33a06f1300a79cfd461cea0268f05e969d4f34ec ]
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) ... [<c076bf3c>] (usb_del_gadget_udc) from [<c0726bec>] (dwc2_hsotg_remove+0x10/0x20) [<c0726bec>] (dwc2_hsotg_remove) from [<c0711208>] (dwc2_driver_probe+0x57c/0x69c) [<c0711208>] (dwc2_driver_probe) from [<c06247c0>] (platform_drv_probe+0x6c/0xa4) [<c06247c0>] (platform_drv_probe) from [<c0621df4>] (really_probe+0x200/0x48c) [<c0621df4>] (really_probe) from [<c06221e8>] (driver_probe_device+0x78/0x1fc) [<c06221e8>] (driver_probe_device) from [<c061fcd4>] (bus_for_each_drv+0x74/0xb8) [<c061fcd4>] (bus_for_each_drv) from [<c0621b54>] (__device_attach+0xd4/0x16c) [<c0621b54>] (__device_attach) from [<c0620c98>] (bus_probe_device+0x88/0x90) [<c0620c98>] (bus_probe_device) from [<c06211b0>] (deferred_probe_work_func+0x3c/0xd0) [<c06211b0>] (deferred_probe_work_func) from [<c0149280>] (process_one_work+0x234/0x7dc) [<c0149280>] (process_one_work) from [<c014986c>] (worker_thread+0x44/0x51c) [<c014986c>] (worker_thread) from [<c0150b1c>] (kthread+0x158/0x1a0) [<c0150b1c>] (kthread) from [<c0100114>] (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 hminas@synopsys.com Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com Signed-off-by: Felipe Balbi balbi@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 c35c93f16a49a..a9e86f5e6eaa3 100644 --- a/drivers/usb/dwc2/platform.c +++ b/drivers/usb/dwc2/platform.c @@ -499,6 +499,7 @@ 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; } @@ -507,7 +508,8 @@ static int dwc2_driver_probe(struct platform_device *dev) return 0;
error: - dwc2_lowlevel_hw_disable(hsotg); + if (hsotg->dr_mode != USB_DR_MODE_PERIPHERAL) + dwc2_lowlevel_hw_disable(hsotg); return retval; }