Hi Changbin, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on linus/master] [also build test WARNING on v4.17-rc4 next-20180510] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/changbin-du-intel-com/kernel-hacking-GCC-optimization-for-better-debug-experience-Og/20180509-213955 config: x86_64-randconfig-s1-05100951 (attached as .config) compiler: gcc-6 (Debian 6.4.0-9) 6.4.0 20171026 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings All warnings (new ones prefixed by >>): drivers//net/wireless/zydas/zd1201.c: In function 'zd1201_get_freq': >> drivers//net/wireless/zydas/zd1201.c:939:10: warning: 'channel' may be used uninitialized in this function [-Wmaybe-uninitialized] freq->m = channel; ~~~~~~~~^~~~~~~~~ drivers//net/wireless/zydas/zd1201.c: In function 'zd1201_get_mode': >> drivers//net/wireless/zydas/zd1201.c:1016:2: warning: 'porttype' may be used uninitialized in this function [-Wmaybe-uninitialized] switch(porttype) { ^~~~~~ drivers//net/wireless/zydas/zd1201.c: In function 'zd1201_get_rate': >> drivers//net/wireless/zydas/zd1201.c:1282:2: warning: 'rate' may be used uninitialized in this function [-Wmaybe-uninitialized] switch(rate) { ^~~~~~ drivers//net/wireless/zydas/zd1201.c: In function 'zd1201_get_rts': >> drivers//net/wireless/zydas/zd1201.c:1334:13: warning: 'rtst' may be used uninitialized in this function [-Wmaybe-uninitialized] rts->value = rtst; ~~~~~~~~~~~^~~~~~ drivers//net/wireless/zydas/zd1201.c: In function 'zd1201_get_frag': >> drivers//net/wireless/zydas/zd1201.c:1372:14: warning: 'fragt' may be used uninitialized in this function [-Wmaybe-uninitialized] frag->value = fragt; ~~~~~~~~~~~~^~~~~~~ drivers//net/wireless/zydas/zd1201.c: In function 'zd1201_set_power': >> drivers//net/wireless/zydas/zd1201.c:1503:28: warning: 'duration' may be used uninitialized in this function [-Wmaybe-uninitialized] level = vwrq->value * 4 / duration; ~~~~~~~~~~~~~~~~^~~~~~~~~~ drivers//net/wireless/zydas/zd1201.c: In function 'zd1201_get_power': drivers//net/wireless/zydas/zd1201.c:1542:27: warning: 'duration' may be used uninitialized in this function [-Wmaybe-uninitialized] vwrq->value = duration * level / 4; ~~~~~~~~~^~~~~~~ >> drivers//net/wireless/zydas/zd1201.c:1547:15: warning: 'level' may be used uninitialized in this function [-Wmaybe-uninitialized] if (enabled && level) ~~~~~~~~^~~~~~~~ >> drivers//net/wireless/zydas/zd1201.c:1547:6: warning: 'enabled' may be used uninitialized in this function [-Wmaybe-uninitialized] if (enabled && level) ^ drivers//net/wireless/zydas/zd1201.c: In function 'zd1201_get_hostauth': >> drivers//net/wireless/zydas/zd1201.c:1631:13: warning: 'hostauth' may be used uninitialized in this function [-Wmaybe-uninitialized] rrq->value = hostauth; ~~~~~~~~~~~^~~~~~~~~~ drivers//net/wireless/zydas/zd1201.c: In function 'zd1201_get_maxassoc': >> drivers//net/wireless/zydas/zd1201.c:1681:13: warning: 'maxassoc' may be used uninitialized in this function [-Wmaybe-uninitialized] rrq->value = maxassoc; ~~~~~~~~~~~^~~~~~~~~~ -- drivers/rtc/rtc-da9052.c: In function 'da9052_read_alarm': >> drivers/rtc/rtc-da9052.c:25:3: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized] dev_err(rtc->da9052->dev, "%s: " fmt, __func__, ##__VA_ARGS__) ^~~~~~~ In file included from drivers/rtc/rtc-da9052.c:21:0: include/linux/mfd/da9052/da9052.h:157:6: note: 'ret' was declared here int ret; ^~~ >> drivers/rtc/rtc-da9052.c:25:3: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized] dev_err(rtc->da9052->dev, "%s: " fmt, __func__, ##__VA_ARGS__) ^~~~~~~ In file included from drivers/rtc/rtc-da9052.c:21:0: include/linux/mfd/da9052/da9052.h:157:6: note: 'ret' was declared here int ret; ^~~ drivers/rtc/rtc-da9052.c: In function 'da9052_rtc_read_time': >> drivers/rtc/rtc-da9052.c:25:3: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized] dev_err(rtc->da9052->dev, "%s: " fmt, __func__, ##__VA_ARGS__) ^~~~~~~ In file included from drivers/rtc/rtc-da9052.c:21:0: include/linux/mfd/da9052/da9052.h:157:6: note: 'ret' was declared here int ret; ^~~ >> drivers/rtc/rtc-da9052.c:25:3: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized] dev_err(rtc->da9052->dev, "%s: " fmt, __func__, ##__VA_ARGS__) ^~~~~~~ In file included from drivers/rtc/rtc-da9052.c:21:0: include/linux/mfd/da9052/da9052.h:157:6: note: 'ret' was declared here int ret; ^~~ -- net/bluetooth/mgmt.c: In function 'read_local_oob_ext_data_complete': >> net/bluetooth/mgmt.c:5669:27: warning: 'r256' may be used uninitialized in this function [-Wmaybe-uninitialized] u8 *h192, *r192, *h256, *r256; ^~~~ -- In file included from drivers//net/wireless/zydas/zd1211rw/zd_usb.c:28:0: drivers//net/wireless/zydas/zd1211rw/zd_usb.c: In function 'eject_installer': >> include/linux/usb.h:1922:23: warning: 'bulk_out_ep' may be used uninitialized in this function [-Wmaybe-uninitialized] ((PIPE_BULK << 30) | __create_pipe(dev, endpoint)) ^~~~~~~~~~~~~ drivers//net/wireless/zydas/zd1211rw/zd_usb.c:1278:5: note: 'bulk_out_ep' was declared here u8 bulk_out_ep; ^~~~~~~~~~~ -- drivers/slimbus/messaging.c: In function 'slim_do_transfer': >> drivers/slimbus/messaging.c:126:4: warning: 'tid' may be used uninitialized in this function [-Wmaybe-uninitialized] idr_remove(&ctrl->tid_idr, tid); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- drivers//staging/comedi/drivers/serial2002.c: In function 'serial2002_setup_subdevs': >> drivers//staging/comedi/drivers/serial2002.c:497:7: warning: 'cfg' may be used uninitialized in this function [-Wmaybe-uninitialized] if (serial2002_setup_subdevice(s, cfg, range, mapping, kind)) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- In file included from drivers/net/wireless/zydas/zd1211rw/zd_usb.c:28:0: drivers/net/wireless/zydas/zd1211rw/zd_usb.c: In function 'eject_installer': >> include/linux/usb.h:1922:23: warning: 'bulk_out_ep' may be used uninitialized in this function [-Wmaybe-uninitialized] ((PIPE_BULK << 30) | __create_pipe(dev, endpoint)) ^~~~~~~~~~~~~ drivers/net/wireless/zydas/zd1211rw/zd_usb.c:1278:5: note: 'bulk_out_ep' was declared here u8 bulk_out_ep; ^~~~~~~~~~~ -- drivers//regulator/max8925-regulator.c: In function 'max8925_regulator_probe': >> drivers//regulator/max8925-regulator.c:315:3: warning: 'ri' may be used uninitialized in this function [-Wmaybe-uninitialized] dev_err(&pdev->dev, "failed to register regulator %s\n", ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ri->desc.name); ~~~~~~~~~~~~~~ -- drivers//bcma/sprom.c: In function 'bcma_sprom_get': >> drivers//bcma/sprom.c:642:3: warning: 'sprom' may be used uninitialized in this function [-Wmaybe-uninitialized] kfree(sprom); ^~~~~~~~~~~~ -- drivers//block/rbd.c: In function 'rbd_v2_snap_id_by_name': >> drivers//block/rbd.c:4797:25: warning: 'snap_id' may be used uninitialized in this function [-Wmaybe-uninitialized] return found ? snap_id : CEPH_NOSNAP; drivers//block/rbd.c: In function 'rbd_dev_image_id': >> drivers//block/rbd.c:5349:27: warning: 'image_id' may be used uninitialized in this function [-Wmaybe-uninitialized] rbd_dev->spec->image_id = image_id; ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~ -- drivers//firmware/qemu_fw_cfg.c: In function 'fw_cfg_build_symlink': >> drivers//firmware/qemu_fw_cfg.c:557:9: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized] return ret; ^~~ .. vim +/seq +33 include/linux/compiler.h 1f0d69a9 Steven Rostedt 2008-11-12 22 d45ae1f7 Steven Rostedt (VMware 2017-01-17 23) #define __branch_check__(x, expect, is_constant) ({ \ 1f0d69a9 Steven Rostedt 2008-11-12 24 int ______r; \ 134e6a03 Steven Rostedt (VMware 2017-01-19 25) static struct ftrace_likely_data \ 1f0d69a9 Steven Rostedt 2008-11-12 26 __attribute__((__aligned__(4))) \ 45b79749 Steven Rostedt 2008-11-21 27 __attribute__((section("_ftrace_annotated_branch"))) \ 1f0d69a9 Steven Rostedt 2008-11-12 28 ______f = { \ 134e6a03 Steven Rostedt (VMware 2017-01-19 29) .data.func = __func__, \ 134e6a03 Steven Rostedt (VMware 2017-01-19 30) .data.file = __FILE__, \ 134e6a03 Steven Rostedt (VMware 2017-01-19 31) .data.line = __LINE__, \ 1f0d69a9 Steven Rostedt 2008-11-12 32 }; \ d45ae1f7 Steven Rostedt (VMware 2017-01-17 @33) ______r = __builtin_expect(!!(x), expect); \ d45ae1f7 Steven Rostedt (VMware 2017-01-17 34) ftrace_likely_update(&______f, ______r, \ d45ae1f7 Steven Rostedt (VMware 2017-01-17 35) expect, is_constant); \ 1f0d69a9 Steven Rostedt 2008-11-12 36 ______r; \ 1f0d69a9 Steven Rostedt 2008-11-12 37 }) 1f0d69a9 Steven Rostedt 2008-11-12 38 :::::: The code at line 33 was first introduced by commit :::::: d45ae1f7041ac52ade6c5ec76d96bbed765d67aa tracing: Process constants for (un)likely() profiler :::::: TO: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> :::::: CC: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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