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 >> >> 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") >> ^ >> :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. 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@lists.01.org > >