From: Marek Szyprowski Date: Thu, 16 Jul 2020 11:55:25 +0000 (+0200) Subject: usb: gadget: udc: Flush pending work also in error path X-Git-Tag: v5.10.7~1952^2~35^2~33 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=37d9453b052dec46f6439658536ca8f301566559;p=platform%2Fkernel%2Flinux-rpi.git usb: gadget: udc: Flush pending work also in error path When binding an UDC driver to the pending gadget fails in check_pending_gadget_drivers(), the usb_add_gadget_udc_release() function ends without waiting for the usb_gadget_state_work to finish, what in turn might cause the whole struct usb_gadget being freed by the caller before the usb_gadget_state_work being executed. This can be observed on some boards with USB Mass Storage gadget compiled-in and kernel booted without the needed 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 dwc2: probe of 12480000.hsotg failed with error -22 8<--- cut here --- Unable to handle kernel NULL pointer dereference at virtual address 00000004 pgd = (ptrval) [00000004] *pgd=00000000 Internal error: Oops: 5 [#1] PREEMPT SMP ARM Modules linked in: CPU: 1 PID: 88 Comm: kworker/1:2 Not tainted 5.8.0-rc5-next-20200715-00062-gc5bb489ae825-dirty #8792 Hardware name: Samsung Exynos (Flattened Device Tree) Workqueue: 0x0 (rcu_gp) PC is at process_one_work+0x44/0x7dc ... Process kworker/1:2 (pid: 88, stack limit = 0x(ptrval)) Stack: (0xed9f1f00 to 0xed9f2000) ... [] (process_one_work) from [] (worker_thread+0x44/0x51c) [] (worker_thread) from [] (kthread+0x158/0x1a0) [] (kthread) from [] (ret_from_fork+0x14/0x20) Exception stack(0xed9f1fb0 to 0xed9f1ff8) ... ---[ end trace 5033c1326a62e5f3 ]--- note: kworker/1:2[88] exited with preempt_count 1 Fix this by flushing pending work in error path. Reviewed-by: Peter Chen Signed-off-by: Marek Szyprowski Signed-off-by: Felipe Balbi --- diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index c33ad8a..4f82bcd3 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -1230,6 +1230,7 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget, return 0; err_del_udc: + flush_work(&gadget->work); device_del(&udc->dev); err_unlist_udc: