On Tue, Feb 28, 2017 at 11:07:08AM -0500, Alan Stern wrote: > On Tue, 28 Feb 2017, Peter Chen wrote: > > > When the user does device unbind and rebind test, the kernel will > > show below dump due to usb_gadget memory region is dirty after unbind. > > Clear usb_gadget region for every new probe. > > > > root@imx6qdlsolo:/sys/bus/platform/drivers/dummy_udc# echo dummy_udc.0 > bind > > [ 102.523312] kobject (eddd78b0): tried to init an initialized object, something is seriously wrong. > > [ 102.532447] CPU: 0 PID: 734 Comm: sh Not tainted 4.10.0-rc7-00872-g1b2b8e9 #1298 > > [ 102.539866] Hardware name: Freescale i.MX6 SoloX (Device Tree) > > [ 102.545717] Backtrace: > > [ 102.548225] [<c010d090>] (dump_backtrace) from [<c010d338>] (show_stack+0x18/0x1c) > > [ 102.555822] r7:ede34000 r6:60010013 r5:00000000 r4:c0f29418 > > [ 102.561512] [<c010d320>] (show_stack) from [<c040c2a4>] (dump_stack+0xb4/0xe8) > > [ 102.568764] [<c040c1f0>] (dump_stack) from [<c040e6d4>] (kobject_init+0x80/0x9c) > > [ 102.576187] r10:0000001f r9:eddd7000 r8:eeaf8c10 r7:eddd78a8 r6:c177891c r5:c0f3b060 > > [ 102.584036] r4:eddd78b0 r3:00000000 > > [ 102.587641] [<c040e654>] (kobject_init) from [<c05359a4>] (device_initialize+0x28/0xf8) > > [ 102.595665] r5:eebc4800 r4:eddd78a8 > > [ 102.599268] [<c053597c>] (device_initialize) from [<c05382ac>] (device_register+0x14/0x20) > > [ 102.607556] r7:eddd78a8 r6:00000000 r5:eebc4800 r4:eddd78a8 > > [ 102.613256] [<c0538298>] (device_register) from [<c0668ef4>] (usb_add_gadget_udc_release+0x8c/0x1ec) > > [ 102.622410] r5:eebc4800 r4:eddd7860 > > [ 102.626015] [<c0668e68>] (usb_add_gadget_udc_release) from [<c0669068>] (usb_add_gadget_udc+0x14/0x18) > > [ 102.635351] r10:0000001f r9:eddd7000 r8:eddd788c r7:bf003770 r6:eddd77f8 r5:eddd7818 > > [ 102.643198] r4:eddd785c r3:eddd7b24 > > [ 102.646834] [<c0669054>] (usb_add_gadget_udc) from [<bf003428>] (dummy_udc_probe+0x170/0x1c4 [dummy_hcd]) > > [ 102.656458] [<bf0032b8>] (dummy_udc_probe [dummy_hcd]) from [<c053d114>] (platform_drv_probe+0x54/0xb8) > > [ 102.665881] r10:00000008 r9:c1778960 r8:bf004128 r7:fffffdfb r6:bf004128 r5:eeaf8c10 > > [ 102.673727] r4:eeaf8c10 > > [ 102.676293] [<c053d0c0>] (platform_drv_probe) from [<c053b160>] (driver_probe_device+0x264/0x474) > > [ 102.685186] r7:00000000 r6:00000000 r5:c1778960 r4:eeaf8c10 > > [ 102.690876] [<c053aefc>] (driver_probe_device) from [<c05397c4>] (bind_store+0xb8/0x14c) > > [ 102.698994] r10:eeb3bb4c r9:ede34000 r8:0000000c r7:eeaf8c44 r6:bf004128 r5:c0f3b668 > > [ 102.706840] r4:eeaf8c10 > > [ 102.709402] [<c053970c>] (bind_store) from [<c0538ca8>] (drv_attr_store+0x28/0x34) > > [ 102.716998] r9:ede34000 r8:00000000 r7:ee3863c0 r6:ee3863c0 r5:c0538c80 r4:c053970c > > [ 102.724776] [<c0538c80>] (drv_attr_store) from [<c029c930>] (sysfs_kf_write+0x50/0x54) > > [ 102.732711] r5:c0538c80 r4:0000000c > > [ 102.736313] [<c029c8e0>] (sysfs_kf_write) from [<c029be84>] (kernfs_fop_write+0x100/0x214) > > [ 102.744599] r7:ee3863c0 r6:eeb3bb40 r5:00000000 r4:00000000 > > [ 102.750287] [<c029bd84>] (kernfs_fop_write) from [<c0222dd8>] (__vfs_write+0x34/0x120) > > [ 102.758231] r10:00000000 r9:ede34000 r8:c0108bc4 r7:0000000c r6:ede35f80 r5:c029bd84 > > [ 102.766077] r4:ee223780 > > [ 102.768638] [<c0222da4>] (__vfs_write) from [<c0224678>] (vfs_write+0xa8/0x170) > > [ 102.775974] r9:ede34000 r8:c0108bc4 r7:ede35f80 r6:01861cb0 r5:ee223780 r4:0000000c > > [ 102.783743] [<c02245d0>] (vfs_write) from [<c0225498>] (SyS_write+0x4c/0xa8) > > [ 102.790818] r9:ede34000 r8:c0108bc4 r7:0000000c r6:01861cb0 r5:ee223780 r4:ee223780 > > [ 102.798595] [<c022544c>] (SyS_write) from [<c0108a20>] (ret_fast_syscall+0x0/0x1c) > > [ 102.806188] r7:00000004 r6:b6e83d58 r5:01861cb0 r4:0000000c > > > > Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > > Cc: stable <stable@xxxxxxxxxxxxxxx> > > Fixes: 90fccb529d24 ("usb: gadget: Gadget directory cleanup - group UDC drivers") > > Signed-off-by: Peter Chen <peter.chen@xxxxxxx> > > Tested-by: Xiaolong Ye <xiaolong.ye@xxxxxxxxx> > > Reported-by: Fengguang Wu <fengguang.wu@xxxxxxxxx> > > --- > > drivers/usb/gadget/udc/dummy_hcd.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c > > index c60abe3..8cabc59 100644 > > --- a/drivers/usb/gadget/udc/dummy_hcd.c > > +++ b/drivers/usb/gadget/udc/dummy_hcd.c > > @@ -1031,6 +1031,8 @@ static int dummy_udc_probe(struct platform_device *pdev) > > int rc; > > > > dum = *((void **)dev_get_platdata(&pdev->dev)); > > + /* Clear usb_gadget region for new registration to udc-core */ > > + memzero_explicit(&dum->gadget, sizeof(struct usb_gadget)); > > dum->gadget.name = gadget_name; > > dum->gadget.ops = &dummy_ops; > > dum->gadget.max_speed = USB_SPEED_SUPER; > > Wouldn't it be better to clear the entire structure, not just > dum->gadget? Then you could also change > > dum[i] = kzalloc(sizeof(struct dummy), GFP_KERNEL); > > to use kmalloc, since the structure will be initialized by the probe > routine. > The memory region of dum is shared between dummy_hcd and dummy_udc. If clear entire dum, the entries for dummy_hcd will be cleared. -- Best Regards, Peter Chen