tree: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git test head: 685a26bc60076305987bf06cfd1269e5e4094c73 commit: 685a26bc60076305987bf06cfd1269e5e4094c73 [69/69] rcu/nocb: Avoid ->nocb_lock capture by corresponding CPU config: arm-realview_defconfig (attached as .config) compiler: arm-linux-gnueabi-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 685a26bc60076305987bf06cfd1269e5e4094c73 # save the attached .config to linux build tree GCC_VERSION=7.4.0 make.cross ARCH=arm
If you fix the issue, kindly add following tag Reported-by: kbuild test robot <[email protected]> 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:1891:2: warning: 'flags' may be used uninitialized in this function [-Wmaybe-uninitialized] wake_nocb_gp(rdp, ndw == RCU_NOCB_WAKE_FORCE, flags); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from include/linux/irqflags.h:16:0, from arch/arm/include/asm/bitops.h:28, from include/linux/bitops.h:19, from include/linux/kernel.h:12, from kernel/rcu/tree.c:21: kernel/rcu/tree_plugin.h: In function 'rcu_nocb_gp_kthread': >> arch/arm/include/asm/irqflags.h:171:2: warning: 'flags' may be used >> uninitialized in this function [-Wmaybe-uninitialized] asm volatile( ^~~ In file included from kernel/rcu/tree.c:3519:0: kernel/rcu/tree_plugin.h:1719:16: note: 'flags' was declared here unsigned long flags; ^~~~~ -- 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:1891:2: warning: 'flags' may be used uninitialized in this function [-Wmaybe-uninitialized] wake_nocb_gp(rdp, ndw == RCU_NOCB_WAKE_FORCE, flags); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from include/linux/irqflags.h:16:0, from arch/arm/include/asm/bitops.h:28, from include/linux/bitops.h:19, from include/linux/kernel.h:12, from kernel//rcu/tree.c:21: kernel//rcu/tree_plugin.h: In function 'rcu_nocb_gp_kthread': >> arch/arm/include/asm/irqflags.h:171:2: warning: 'flags' may be used >> uninitialized in this function [-Wmaybe-uninitialized] asm volatile( ^~~ In file included from kernel//rcu/tree.c:3519:0: kernel//rcu/tree_plugin.h:1719:16: note: 'flags' was declared here unsigned long flags; ^~~~~ vim +/flags +171 arch/arm/include/asm/irqflags.h 7ad1bcb2 include/asm-arm/irqflags.h Russell King 2006-08-27 164 7ad1bcb2 include/asm-arm/irqflags.h Russell King 2006-08-27 165 /* 7ad1bcb2 include/asm-arm/irqflags.h Russell King 2006-08-27 166 * restore saved IRQ & FIQ state 7ad1bcb2 include/asm-arm/irqflags.h Russell King 2006-08-27 167 */ 6fb18ac9 arch/arm/include/asm/irqflags.h Daniel Thompson 2015-06-10 168 #define arch_local_irq_restore arch_local_irq_restore df9ee292 arch/arm/include/asm/irqflags.h David Howells 2010-10-07 169 static inline void arch_local_irq_restore(unsigned long flags) df9ee292 arch/arm/include/asm/irqflags.h David Howells 2010-10-07 170 { df9ee292 arch/arm/include/asm/irqflags.h David Howells 2010-10-07 @171 asm volatile( 55bdd694 arch/arm/include/asm/irqflags.h Catalin Marinas 2010-05-21 172 " msr " IRQMASK_REG_NAME_W ", %0 @ local_irq_restore" df9ee292 arch/arm/include/asm/irqflags.h David Howells 2010-10-07 173 : df9ee292 arch/arm/include/asm/irqflags.h David Howells 2010-10-07 174 : "r" (flags) df9ee292 arch/arm/include/asm/irqflags.h David Howells 2010-10-07 175 : "memory", "cc"); df9ee292 arch/arm/include/asm/irqflags.h David Howells 2010-10-07 176 } df9ee292 arch/arm/include/asm/irqflags.h David Howells 2010-10-07 177 :::::: The code at line 171 was first introduced by commit :::::: df9ee29270c11dba7d0fe0b83ce47a4d8e8d2101 Fix IRQ flag handling naming :::::: TO: David Howells <[email protected]> :::::: CC: David Howells <[email protected]> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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