On Fri, Jun 18, 2021 at 10:04:58AM -0700, Nathan Chancellor wrote: > On 6/18/2021 1:44 AM, Sean Young wrote: > > On Fri, Jun 18, 2021 at 06:18:06AM +0800, kernel test robot wrote: > > > Hi Sean, > > > > > > I love your patch! Perhaps something to improve: > > > > > > [auto build test WARNING on linuxtv-media/master] > > > [also build test WARNING on usb-serial/usb-next usb/usb-testing peter.chen-usb/for-usb-next v5.13-rc6 next-20210617] > > > [If your patch is applied to the wrong git tree, kindly drop us a note. > > > And when submitting patch, we suggest to use '--base' as documented in > > > https://git-scm.com/docs/git-format-patch] > > > > > > url: https://github.com/0day-ci/linux/commits/Sean-Young/IR-driver-for-USB-UIRT-device/20210616-182135 > > > base: git://linuxtv.org/media_tree.git master > > > config: powerpc64-randconfig-r012-20210617 (attached as .config) > > > compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 64720f57bea6a6bf033feef4a5751ab9c0c3b401) > > > reproduce (this is a W=1 build): > > > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > > > chmod +x ~/bin/make.cross > > > # install powerpc64 cross compiling tool for clang build > > > # apt-get install binutils-powerpc64-linux-gnu > > > # https://github.com/0day-ci/linux/commit/17d3a0332baecb0359e05e8ae755478c7a1a4468 > > > git remote add linux-review https://github.com/0day-ci/linux > > > git fetch --no-tags linux-review Sean-Young/IR-driver-for-USB-UIRT-device/20210616-182135 > > > git checkout 17d3a0332baecb0359e05e8ae755478c7a1a4468 > > > # save the attached .config to linux build tree > > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64 > > > > > > If you fix the issue, kindly add following tag as appropriate > > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > > > > > All warnings (new ones prefixed by >>): > > > > > > In file included from drivers/media/rc/uirt.c:11: > > > In file included from include/linux/completion.h:12: > > > In file included from include/linux/swait.h:5: > > > In file included from include/linux/list.h:9: > > > In file included from include/linux/kernel.h:12: > > > In file included from include/linux/bitops.h:32: > > > In file included from arch/powerpc/include/asm/bitops.h:62: > > > arch/powerpc/include/asm/barrier.h:49:9: warning: '__lwsync' macro redefined [-Wmacro-redefined] > > > #define __lwsync() __asm__ __volatile__ (stringify_in_c(LWSYNC) : : :"memory") > > > ^ > > > <built-in>:310:9: note: previous definition is here > > > #define __lwsync __builtin_ppc_lwsync > > > ^ > > > > > drivers/media/rc/uirt.c:639:6: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] > > > if (!urb) > > > ^~~~ > > > drivers/media/rc/uirt.c:705:9: note: uninitialized use occurs here > > > return err; > > > > This is interesting. clang is right here, there are error paths where err is > > not initialized. gcc-11.1 does not pick this up for some reason. The error path > > should be an immediate dominator so it shouldn't be complicated to detect. > > The reason GCC does not warn about this is due to commit 78a5255ffb6a ("Stop > the ad-hoc games with -Wno-maybe-initialized"), which disables the GCC > version of this warning except with W=2, which very few people use. You > could use 'KCFLAGS=-Wmaybe-uninitialized' to try and see the same warning. You're right, this is exactly the issue here. When running with W=2 or KCFLAGS=-Wmaybe-uninitialized you do get the warning. There are paths where err are initialized, so gcc correctly says: warning: ‘err’ may be used uninitialized in this function [-Wmaybe-uninitialized] Thanks, Sean > > Cheers, > Nathan > > > I'll send out a v5 with this issue fixed. > > > > Sean > > > > > ^~~ > > > drivers/media/rc/uirt.c:639:2: note: remove the 'if' if its condition is always false > > > if (!urb) > > > ^~~~~~~~~ > > > drivers/media/rc/uirt.c:630:6: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] > > > if (!urb) > > > ^~~~ > > > drivers/media/rc/uirt.c:705:9: note: uninitialized use occurs here > > > return err; > > > ^~~ > > > drivers/media/rc/uirt.c:630:2: note: remove the 'if' if its condition is always false > > > if (!urb) > > > ^~~~~~~~~ > > > drivers/media/rc/uirt.c:626:6: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] > > > if (!rc) > > > ^~~ > > > drivers/media/rc/uirt.c:705:9: note: uninitialized use occurs here > > > return err; > > > ^~~ > > > drivers/media/rc/uirt.c:626:2: note: remove the 'if' if its condition is always false > > > if (!rc) > > > ^~~~~~~~ > > > drivers/media/rc/uirt.c:622:6: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] > > > if (!uirt->out) > > > ^~~~~~~~~~ > > > drivers/media/rc/uirt.c:705:9: note: uninitialized use occurs here > > > return err; > > > ^~~ > > > drivers/media/rc/uirt.c:622:2: note: remove the 'if' if its condition is always false > > > if (!uirt->out) > > > ^~~~~~~~~~~~~~~ > > > drivers/media/rc/uirt.c:618:6: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] > > > if (!uirt->in) > > > ^~~~~~~~~ > > > drivers/media/rc/uirt.c:705:9: note: uninitialized use occurs here > > > return err; > > > ^~~ > > > drivers/media/rc/uirt.c:618:2: note: remove the 'if' if its condition is always false > > > if (!uirt->in) > > > ^~~~~~~~~~~~~~ > > > drivers/media/rc/uirt.c:604:15: note: initialize the variable 'err' to silence this warning > > > int pipe, err; > > > ^ > > > = 0 > > > 6 warnings generated. > > > > > > > > > vim +639 drivers/media/rc/uirt.c > > > > > > 594 > > > 595 static int uirt_probe(struct usb_interface *intf, > > > 596 const struct usb_device_id *id) > > > 597 { > > > 598 struct usb_device *usbdev = interface_to_usbdev(intf); > > > 599 struct usb_endpoint_descriptor *ep_in; > > > 600 struct usb_endpoint_descriptor *ep_out; > > > 601 struct uirt *uirt; > > > 602 struct rc_dev *rc; > > > 603 struct urb *urb; > > > 604 int pipe, err; > > > 605 > > > 606 if (usb_find_common_endpoints(intf->cur_altsetting, &ep_in, &ep_out, NULL, NULL) || > > > 607 usb_endpoint_maxp(ep_in) != MAX_PACKET || > > > 608 usb_endpoint_maxp(ep_out) != MAX_PACKET) { > > > 609 dev_err(&intf->dev, "required endpoints not found\n"); > > > 610 return -ENODEV; > > > 611 } > > > 612 > > > 613 uirt = kzalloc(sizeof(*uirt), GFP_KERNEL); > > > 614 if (!uirt) > > > 615 return -ENOMEM; > > > 616 > > > 617 uirt->in = kmalloc(MAX_PACKET, GFP_KERNEL); > > > 618 if (!uirt->in) > > > 619 goto free_uirt; > > > 620 > > > 621 uirt->out = kmalloc(MAX_PACKET, GFP_KERNEL); > > > 622 if (!uirt->out) > > > 623 goto free_uirt; > > > 624 > > > 625 rc = rc_allocate_device(RC_DRIVER_IR_RAW); > > > 626 if (!rc) > > > 627 goto free_uirt; > > > 628 > > > 629 urb = usb_alloc_urb(0, GFP_KERNEL); > > > 630 if (!urb) > > > 631 goto free_rcdev; > > > 632 > > > 633 pipe = usb_rcvbulkpipe(usbdev, ep_in->bEndpointAddress); > > > 634 usb_fill_bulk_urb(urb, usbdev, pipe, uirt->in, MAX_PACKET, > > > 635 uirt_in_callback, uirt); > > > 636 uirt->urb_in = urb; > > > 637 > > > 638 urb = usb_alloc_urb(0, GFP_KERNEL); > > > > 639 if (!urb) > > > 640 goto free_rcdev; > > > 641 > > > 642 pipe = usb_sndbulkpipe(usbdev, ep_out->bEndpointAddress); > > > 643 usb_fill_bulk_urb(urb, usbdev, pipe, uirt->out, MAX_PACKET, > > > 644 uirt_out_callback, uirt); > > > 645 > > > 646 uirt->dev = &intf->dev; > > > 647 uirt->usbdev = usbdev; > > > 648 uirt->rc = rc; > > > 649 uirt->urb_out = urb; > > > 650 uirt->rx_state = RX_STATE_INTERSPACE_HIGH; > > > 651 > > > 652 err = usb_submit_urb(uirt->urb_in, GFP_KERNEL); > > > 653 if (err != 0) { > > > 654 dev_err(uirt->dev, "failed to submit read urb: %d\n", err); > > > 655 goto free_rcdev; > > > 656 } > > > 657 > > > 658 err = init_ftdi(usbdev); > > > 659 if (err) { > > > 660 dev_err(uirt->dev, "failed to setup ftdi: %d\n", err); > > > 661 goto kill_urbs; > > > 662 } > > > 663 > > > 664 err = uirt_setup(uirt); > > > 665 if (err) > > > 666 goto kill_urbs; > > > 667 > > > 668 usb_make_path(usbdev, uirt->phys, sizeof(uirt->phys)); > > > 669 > > > 670 rc->device_name = "USB-UIRT"; > > > 671 rc->driver_name = KBUILD_MODNAME; > > > 672 rc->input_phys = uirt->phys; > > > 673 usb_to_input_id(usbdev, &rc->input_id); > > > 674 rc->dev.parent = &intf->dev; > > > 675 rc->priv = uirt; > > > 676 rc->tx_ir = uirt_tx; > > > 677 rc->s_tx_carrier = uirt_set_tx_carrier; > > > 678 rc->s_learning_mode = uirt_set_rx_wideband; > > > 679 rc->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER; > > > 680 rc->map_name = RC_MAP_RC6_MCE; > > > 681 rc->rx_resolution = UNIT_US; > > > 682 rc->timeout = IR_TIMEOUT; > > > 683 > > > 684 uirt_set_tx_carrier(rc, 38000); > > > 685 > > > 686 err = rc_register_device(rc); > > > 687 if (err) > > > 688 goto kill_urbs; > > > 689 > > > 690 usb_set_intfdata(intf, uirt); > > > 691 > > > 692 return 0; > > > 693 > > > 694 kill_urbs: > > > 695 usb_kill_urb(uirt->urb_in); > > > 696 usb_kill_urb(uirt->urb_out); > > > 697 free_rcdev: > > > 698 usb_free_urb(uirt->urb_in); > > > 699 usb_free_urb(uirt->urb_out); > > > 700 rc_free_device(rc); > > > 701 free_uirt: > > > 702 kfree(uirt->in); > > > 703 kfree(uirt->out); > > > 704 kfree(uirt); > > > 705 return err; > > > 706 } > > > 707 > > > > > > --- > > > 0-DAY CI Kernel Test Service, Intel Corporation > > > https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx > > > >
