| Message ID | 20220505104618.22729-1-m.szyprowski@samsung.com |
|---|---|
| State | New |
| Headers | show |
| Series | usb: dwc2: gadget: don't reset gadget's driver->bus | expand |
On 5/5/2022 2:46 PM, Marek Szyprowski wrote: > UDC driver should not touch gadget's driver internals, especially it > should not reset driver->bus. This wasn't harmful so far, but since > commit fc274c1e9973 ("USB: gadget: Add a new bus for gadgets") gadget > subsystem got it's own bus and messing with ->bus triggers the > following NULL pointer dereference: > > dwc2 12480000.hsotg: bound driver g_ether > 8<--- cut here --- > Unable to handle kernel NULL pointer dereference at virtual address 00000000 > [00000000] *pgd=00000000 > Internal error: Oops: 5 [#1] SMP ARM > Modules linked in: ... > CPU: 0 PID: 620 Comm: modprobe Not tainted 5.18.0-rc5-next-20220504 #11862 > Hardware name: Samsung Exynos (Flattened Device Tree) > PC is at module_add_driver+0x44/0xe8 > LR is at sysfs_do_create_link_sd+0x84/0xe0 > ... > Process modprobe (pid: 620, stack limit = 0x(ptrval)) > ... > module_add_driver from bus_add_driver+0xf4/0x1e4 > bus_add_driver from driver_register+0x78/0x10c > driver_register from usb_gadget_register_driver_owner+0x40/0xb4 > usb_gadget_register_driver_owner from do_one_initcall+0x44/0x1e0 > do_one_initcall from do_init_module+0x44/0x1c8 > do_init_module from load_module+0x19b8/0x1b9c > load_module from sys_finit_module+0xdc/0xfc > sys_finit_module from ret_fast_syscall+0x0/0x54 > Exception stack(0xf1771fa8 to 0xf1771ff0) > ... > dwc2 12480000.hsotg: new device is high-speed > ---[ end trace 0000000000000000 ]--- > > Fix this by removing driver->bus entry reset. > > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Minas Harutyunyan <hminas@synopsys.com> > --- > drivers/usb/dwc2/gadget.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c > index eee3504397e6..fe2a58c75861 100644 > --- a/drivers/usb/dwc2/gadget.c > +++ b/drivers/usb/dwc2/gadget.c > @@ -4544,7 +4544,6 @@ static int dwc2_hsotg_udc_start(struct usb_gadget *gadget, > > WARN_ON(hsotg->driver); > > - driver->driver.bus = NULL; > hsotg->driver = driver; > hsotg->gadget.dev.of_node = hsotg->dev->of_node; > hsotg->gadget.speed = USB_SPEED_UNKNOWN;
diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c index eee3504397e6..fe2a58c75861 100644 --- a/drivers/usb/dwc2/gadget.c +++ b/drivers/usb/dwc2/gadget.c @@ -4544,7 +4544,6 @@ static int dwc2_hsotg_udc_start(struct usb_gadget *gadget, WARN_ON(hsotg->driver); - driver->driver.bus = NULL; hsotg->driver = driver; hsotg->gadget.dev.of_node = hsotg->dev->of_node; hsotg->gadget.speed = USB_SPEED_UNKNOWN;
UDC driver should not touch gadget's driver internals, especially it should not reset driver->bus. This wasn't harmful so far, but since commit fc274c1e9973 ("USB: gadget: Add a new bus for gadgets") gadget subsystem got it's own bus and messing with ->bus triggers the following NULL pointer dereference: dwc2 12480000.hsotg: bound driver g_ether 8<--- cut here --- Unable to handle kernel NULL pointer dereference at virtual address 00000000 [00000000] *pgd=00000000 Internal error: Oops: 5 [#1] SMP ARM Modules linked in: ... CPU: 0 PID: 620 Comm: modprobe Not tainted 5.18.0-rc5-next-20220504 #11862 Hardware name: Samsung Exynos (Flattened Device Tree) PC is at module_add_driver+0x44/0xe8 LR is at sysfs_do_create_link_sd+0x84/0xe0 ... Process modprobe (pid: 620, stack limit = 0x(ptrval)) ... module_add_driver from bus_add_driver+0xf4/0x1e4 bus_add_driver from driver_register+0x78/0x10c driver_register from usb_gadget_register_driver_owner+0x40/0xb4 usb_gadget_register_driver_owner from do_one_initcall+0x44/0x1e0 do_one_initcall from do_init_module+0x44/0x1c8 do_init_module from load_module+0x19b8/0x1b9c load_module from sys_finit_module+0xdc/0xfc sys_finit_module from ret_fast_syscall+0x0/0x54 Exception stack(0xf1771fa8 to 0xf1771ff0) ... dwc2 12480000.hsotg: new device is high-speed ---[ end trace 0000000000000000 ]--- Fix this by removing driver->bus entry reset. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- drivers/usb/dwc2/gadget.c | 1 - 1 file changed, 1 deletion(-)