tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git test head: 77ef1b88654653681661fb0ce7cc1d6e712a409f commit: 6ad9e6bcf543a758d4b7323cb2909ebd66f39ee4 [70/72] fixup! rcu/nocb: Avoid ->nocb_lock capture by corresponding CPU config: sparc64-allmodconfig (attached as .config) compiler: sparc64-linux-gcc (GCC) 7.4.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross git checkout 6ad9e6bcf543a758d4b7323cb2909ebd66f39ee4 # save the attached .config to linux build tree GCC_VERSION=7.4.0 make.cross ARCH=sparc64
If you fix the issue, kindly add following tag Reported-by: kbuild test robot <l...@intel.com> 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 >>): In file included from kernel/rcu/tree.c:3519:0: kernel/rcu/tree_plugin.h: In function 'do_nocb_deferred_wakeup_common': >> kernel/rcu/tree_plugin.h:1888:3: warning: 'flags' may be used uninitialized >> in this function [-Wmaybe-uninitialized] rcu_nocb_unlock_irqrestore(rdp, flags); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/rcu/tree_plugin.h: In function 'rcu_nocb_gp_kthread': kernel/rcu/tree_plugin.h:1790:3: warning: 'flags' may be used uninitialized in this function [-Wmaybe-uninitialized] rcu_nocb_unlock_irqrestore(my_rdp, flags); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/rcu/tree_plugin.h:1721:16: note: 'flags' was declared here unsigned long flags; ^~~~~ vim +/flags +1888 kernel/rcu/tree_plugin.h 1879 1880 /* Do a deferred wakeup of rcu_nocb_kthread(). */ 1881 static void do_nocb_deferred_wakeup_common(struct rcu_data *rdp) 1882 { 1883 unsigned long flags; 1884 int ndw; 1885 1886 rcu_nocb_lock_irqsave(rdp, flags); 1887 if (!rcu_nocb_need_deferred_wakeup(rdp)) { > 1888 rcu_nocb_unlock_irqrestore(rdp, flags); 1889 return; 1890 } 1891 ndw = READ_ONCE(rdp->nocb_defer_wakeup); 1892 WRITE_ONCE(rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_NOT); 1893 wake_nocb_gp(rdp, ndw == RCU_NOCB_WAKE_FORCE, flags); 1894 trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("DeferredWake")); 1895 } 1896 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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