| Message ID | 20190822134028.2623-1-rogerq@ti.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 163be6ff7739b12ff300d77897d340f661821da2 |
| Headers | show |
| Series | [v2] usb: gadget: udc: core: Fix segfault if udc_bind_to_driver() for pending driver fails | expand |
On Thu, 22 Aug 2019, Roger Quadros wrote: > If a gadget driver is in the pending drivers list, a UDC > becomes available and udc_bind_to_driver() fails, then it > gets deleted from the pending list. > i.e. list_del(&driver->pending) in check_pending_gadget_drivers(). > > Then if that gadget driver is unregistered, > usb_gadget_unregister_driver() does a list_del(&driver->pending) > again thus causing a page fault as that list entry has been poisoned > by the previous list_del(). > > Fix this by using list_del_init() instead of list_del() in > check_pending_gadget_drivers(). > > Test case: > > - Make sure no UDC is available > - modprobe g_mass_storage file=wrongfile > - Load UDC driver so it becomes available > lun0: unable to open backing file: wrongfile > - modprobe -r g_mass_storage > > [ 60.900431] Unable to handle kernel paging request at virtual address dead000000000108 > [ 60.908346] Mem abort info: > [ 60.911145] ESR = 0x96000044 > [ 60.914227] Exception class = DABT (current EL), IL = 32 bits > [ 60.920162] SET = 0, FnV = 0 > [ 60.923217] EA = 0, S1PTW = 0 > [ 60.926354] Data abort info: > [ 60.929228] ISV = 0, ISS = 0x00000044 > [ 60.933058] CM = 0, WnR = 1 > [ 60.936011] [dead000000000108] address between user and kernel address ranges > [ 60.943136] Internal error: Oops: 96000044 [#1] PREEMPT SMP > [ 60.948691] Modules linked in: g_mass_storage(-) usb_f_mass_storage libcomposite xhci_plat_hcd xhci_hcd usbcore ti_am335x_adc kfifo_buf omap_rng cdns3 rng_core udc_core crc32_ce xfrm_user crct10dif_ce snd_so6 > [ 60.993995] Process modprobe (pid: 834, stack limit = 0x00000000c2aebc69) > [ 61.000765] CPU: 0 PID: 834 Comm: modprobe Not tainted 4.19.59-01963-g065f42a60499 #92 > [ 61.008658] Hardware name: Texas Instruments SoC (DT) > [ 61.014472] pstate: 60000005 (nZCv daif -PAN -UAO) > [ 61.019253] pc : usb_gadget_unregister_driver+0x7c/0x108 [udc_core] > [ 61.025503] lr : usb_gadget_unregister_driver+0x30/0x108 [udc_core] > [ 61.031750] sp : ffff00001338fda0 > [ 61.035049] x29: ffff00001338fda0 x28: ffff800846d40000 > [ 61.040346] x27: 0000000000000000 x26: 0000000000000000 > [ 61.045642] x25: 0000000056000000 x24: 0000000000000800 > [ 61.050938] x23: ffff000008d7b0d0 x22: ffff0000088b07c8 > [ 61.056234] x21: ffff000001100000 x20: ffff000002020260 > [ 61.061530] x19: ffff0000010ffd28 x18: 0000000000000000 > [ 61.066825] x17: 0000000000000000 x16: 0000000000000000 > [ 61.072121] x15: 0000000000000000 x14: 0000000000000000 > [ 61.077417] x13: ffff000000000000 x12: ffffffffffffffff > [ 61.082712] x11: 0000000000000030 x10: 7f7f7f7f7f7f7f7f > [ 61.088008] x9 : fefefefefefefeff x8 : 0000000000000000 > [ 61.093304] x7 : ffffffffffffffff x6 : 000000000000ffff > [ 61.098599] x5 : 8080000000000000 x4 : 0000000000000000 > [ 61.103895] x3 : ffff000001100020 x2 : ffff800846d40000 > [ 61.109190] x1 : dead000000000100 x0 : dead000000000200 > [ 61.114486] Call trace: > [ 61.116922] usb_gadget_unregister_driver+0x7c/0x108 [udc_core] > [ 61.122828] usb_composite_unregister+0x10/0x18 [libcomposite] > [ 61.128643] msg_cleanup+0x18/0xfce0 [g_mass_storage] > [ 61.133682] __arm64_sys_delete_module+0x17c/0x1f0 > [ 61.138458] el0_svc_common+0x90/0x158 > [ 61.142192] el0_svc_handler+0x2c/0x80 > [ 61.145926] el0_svc+0x8/0xc > [ 61.148794] Code: eb03003f d10be033 54ffff21 a94d0281 (f9000420) > [ 61.154869] ---[ end trace afb22e9b637bd9a7 ]--- > Segmentation fault > > Signed-off-by: Roger Quadros <rogerq@ti.com> > --- > Changelog: > v2 > - Retain policy behaviour if pending gadget driver fails to bind. > > drivers/usb/gadget/udc/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c > index 7cf34beb50df..92af8dc98c3d 100644 > --- a/drivers/usb/gadget/udc/core.c > +++ b/drivers/usb/gadget/udc/core.c > @@ -1143,7 +1143,7 @@ static int check_pending_gadget_drivers(struct usb_udc *udc) > dev_name(&udc->dev)) == 0) { > ret = udc_bind_to_driver(udc, driver); > if (ret != -EPROBE_DEFER) > - list_del(&driver->pending); > + list_del_init(&driver->pending); > break; > } > Acked-by: Alan Stern <stern@rowland.harvard.edu>
diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index 7cf34beb50df..92af8dc98c3d 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -1143,7 +1143,7 @@ static int check_pending_gadget_drivers(struct usb_udc *udc) dev_name(&udc->dev)) == 0) { ret = udc_bind_to_driver(udc, driver); if (ret != -EPROBE_DEFER) - list_del(&driver->pending); + list_del_init(&driver->pending); break; }
If a gadget driver is in the pending drivers list, a UDC becomes available and udc_bind_to_driver() fails, then it gets deleted from the pending list. i.e. list_del(&driver->pending) in check_pending_gadget_drivers(). Then if that gadget driver is unregistered, usb_gadget_unregister_driver() does a list_del(&driver->pending) again thus causing a page fault as that list entry has been poisoned by the previous list_del(). Fix this by using list_del_init() instead of list_del() in check_pending_gadget_drivers(). Test case: - Make sure no UDC is available - modprobe g_mass_storage file=wrongfile - Load UDC driver so it becomes available lun0: unable to open backing file: wrongfile - modprobe -r g_mass_storage [ 60.900431] Unable to handle kernel paging request at virtual address dead000000000108 [ 60.908346] Mem abort info: [ 60.911145] ESR = 0x96000044 [ 60.914227] Exception class = DABT (current EL), IL = 32 bits [ 60.920162] SET = 0, FnV = 0 [ 60.923217] EA = 0, S1PTW = 0 [ 60.926354] Data abort info: [ 60.929228] ISV = 0, ISS = 0x00000044 [ 60.933058] CM = 0, WnR = 1 [ 60.936011] [dead000000000108] address between user and kernel address ranges [ 60.943136] Internal error: Oops: 96000044 [#1] PREEMPT SMP [ 60.948691] Modules linked in: g_mass_storage(-) usb_f_mass_storage libcomposite xhci_plat_hcd xhci_hcd usbcore ti_am335x_adc kfifo_buf omap_rng cdns3 rng_core udc_core crc32_ce xfrm_user crct10dif_ce snd_so6 [ 60.993995] Process modprobe (pid: 834, stack limit = 0x00000000c2aebc69) [ 61.000765] CPU: 0 PID: 834 Comm: modprobe Not tainted 4.19.59-01963-g065f42a60499 #92 [ 61.008658] Hardware name: Texas Instruments SoC (DT) [ 61.014472] pstate: 60000005 (nZCv daif -PAN -UAO) [ 61.019253] pc : usb_gadget_unregister_driver+0x7c/0x108 [udc_core] [ 61.025503] lr : usb_gadget_unregister_driver+0x30/0x108 [udc_core] [ 61.031750] sp : ffff00001338fda0 [ 61.035049] x29: ffff00001338fda0 x28: ffff800846d40000 [ 61.040346] x27: 0000000000000000 x26: 0000000000000000 [ 61.045642] x25: 0000000056000000 x24: 0000000000000800 [ 61.050938] x23: ffff000008d7b0d0 x22: ffff0000088b07c8 [ 61.056234] x21: ffff000001100000 x20: ffff000002020260 [ 61.061530] x19: ffff0000010ffd28 x18: 0000000000000000 [ 61.066825] x17: 0000000000000000 x16: 0000000000000000 [ 61.072121] x15: 0000000000000000 x14: 0000000000000000 [ 61.077417] x13: ffff000000000000 x12: ffffffffffffffff [ 61.082712] x11: 0000000000000030 x10: 7f7f7f7f7f7f7f7f [ 61.088008] x9 : fefefefefefefeff x8 : 0000000000000000 [ 61.093304] x7 : ffffffffffffffff x6 : 000000000000ffff [ 61.098599] x5 : 8080000000000000 x4 : 0000000000000000 [ 61.103895] x3 : ffff000001100020 x2 : ffff800846d40000 [ 61.109190] x1 : dead000000000100 x0 : dead000000000200 [ 61.114486] Call trace: [ 61.116922] usb_gadget_unregister_driver+0x7c/0x108 [udc_core] [ 61.122828] usb_composite_unregister+0x10/0x18 [libcomposite] [ 61.128643] msg_cleanup+0x18/0xfce0 [g_mass_storage] [ 61.133682] __arm64_sys_delete_module+0x17c/0x1f0 [ 61.138458] el0_svc_common+0x90/0x158 [ 61.142192] el0_svc_handler+0x2c/0x80 [ 61.145926] el0_svc+0x8/0xc [ 61.148794] Code: eb03003f d10be033 54ffff21 a94d0281 (f9000420) [ 61.154869] ---[ end trace afb22e9b637bd9a7 ]--- Segmentation fault Signed-off-by: Roger Quadros <rogerq@ti.com> --- Changelog: v2 - Retain policy behaviour if pending gadget driver fails to bind. drivers/usb/gadget/udc/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)