Hi, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on kvm/linux-next] [also build test WARNING on v4.14 next-20171124] [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/Wanpeng-Li/KVM-X86-Fix-softlockup-when-get-the-current-kvmclock-timestamp/20171109-030841 base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next config: i386-allyesconfig (attached as .config) compiler: gcc-7 (Debian 7.2.0-12) 7.2.1 20171025 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 >>): In file included from arch/x86/kvm/x86.h:7:0, from arch/x86/kvm/x86.c:28: arch/x86/kvm/x86.c: In function 'get_kvmclock_ns': >> arch/x86/include/asm/pvclock.h:93:15: warning: '*((void *)&hv_clock+28)' may be used uninitialized in this function [-Wmaybe-uninitialized] u64 offset = pvclock_scale_delta(delta, src->tsc_to_system_mul, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ src->tsc_shift); ~~~~~~~~~~~~~~~ arch/x86/kvm/x86.c:1785:32: note: '*((void *)&hv_clock+28)' was declared here struct pvclock_vcpu_time_info hv_clock; ^~~~~~~~ In file included from arch/x86/kvm/x86.h:7:0, from arch/x86/kvm/x86.c:28: arch/x86/include/asm/pvclock.h:65:2: warning: '*((void *)&hv_clock+24)' may be used uninitialized in this function [-Wmaybe-uninitialized] __asm__ ( ^~~~~~~ arch/x86/kvm/x86.c:1785:32: note: '*((void *)&hv_clock+24)' was declared here struct pvclock_vcpu_time_info hv_clock; ^~~~~~~~ -- In file included from arch/x86//kvm/x86.h:7:0, from arch/x86//kvm/x86.c:28: arch/x86//kvm/x86.c: In function 'get_kvmclock_ns': >> arch/x86/include/asm/pvclock.h:93:15: warning: '*((void *)&hv_clock+28)' may be used uninitialized in this function [-Wmaybe-uninitialized] u64 offset = pvclock_scale_delta(delta, src->tsc_to_system_mul, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ src->tsc_shift); ~~~~~~~~~~~~~~~ arch/x86//kvm/x86.c:1785:32: note: '*((void *)&hv_clock+28)' was declared here struct pvclock_vcpu_time_info hv_clock; ^~~~~~~~ In file included from arch/x86//kvm/x86.h:7:0, from arch/x86//kvm/x86.c:28: arch/x86/include/asm/pvclock.h:65:2: warning: '*((void *)&hv_clock+24)' may be used uninitialized in this function [-Wmaybe-uninitialized] __asm__ ( ^~~~~~~ arch/x86//kvm/x86.c:1785:32: note: '*((void *)&hv_clock+24)' was declared here struct pvclock_vcpu_time_info hv_clock; ^~~~~~~~ vim +93 arch/x86/include/asm/pvclock.h 347bb4448 Zachary Amsden 2010-08-19 88 dce2db0a3 Marcelo Tosatti 2012-11-27 89 static __always_inline a5a1d1c29 Thomas Gleixner 2016-12-21 90 u64 __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, u64 tsc) dce2db0a3 Marcelo Tosatti 2012-11-27 91 { 108b249c4 Paolo Bonzini 2016-09-01 92 u64 delta = tsc - src->tsc_timestamp; a5a1d1c29 Thomas Gleixner 2016-12-21 @93 u64 offset = pvclock_scale_delta(delta, src->tsc_to_system_mul, f7550d076 Minfei Huang 2016-05-27 94 src->tsc_shift); 3aed64f6d Paolo Bonzini 2016-06-09 95 return src->system_time + offset; dce2db0a3 Marcelo Tosatti 2012-11-27 96 } dce2db0a3 Marcelo Tosatti 2012-11-27 97 :::::: The code at line 93 was first introduced by commit :::::: a5a1d1c2914b5316924c7893eb683a5420ebd3be clocksource: Use a plain u64 instead of cycle_t :::::: TO: Thomas Gleixner <tglx@xxxxxxxxxxxxx> :::::: CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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