Hi Waiman, [auto build test WARNING on linus/master] [also build test WARNING on v4.10-rc1 next-20161224] [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/Waiman-Long/futex-Introducing-throughput-optimized-TP-futexes/20161230-020021 config: i386-randconfig-x006-201652 (attached as .config) compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901 reproduce: # save the attached .config to linux build tree make ARCH=i386 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 >>): kernel/futex.c: In function 'futex_lock': >> kernel/futex.c:3776:13: warning: 'rspin_timeout' may be used uninitialized in this function [-Wmaybe-uninitialized] else if (curtime > rspin_timeout) ^ kernel/futex.c:3656:6: note: 'rspin_timeout' was declared here u64 rspin_timeout; ^~~~~~~~~~~~~ vim +/rspin_timeout +3776 kernel/futex.c 3760 3761 if (!owner_task && (reader_value >= 0)) { 3762 int old_count = reader_value; 3763 3764 /* 3765 * Reset timeout value if the old reader 3766 * count is 0 or the reader value changes and 3767 * handoff time hasn't been reached. Otherwise, 3768 * disable reader spinning if the handoff time 3769 * is reached. 3770 */ 3771 reader_value = (uval & FUTEX_TID_MASK); 3772 if (!old_count || (!handoff_set 3773 && (reader_value != old_count))) 3774 rspin_timeout = curtime + 3775 TP_RSPIN_TIMEOUT; > 3776 else if (curtime > rspin_timeout) 3777 reader_value = -1; 3778 } 3779 if (!handoff_set && (curtime > handoff_time)) { 3780 WARN_ON(READ_ONCE(state->handoff_pid)); 3781 WRITE_ONCE(state->handoff_pid, vpid); 3782 3783 /* 3784 * Disable handoff check. --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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