On Thu, 17 Nov 2016 15:29:14 +0800 kbuild test robot <fengguang.wu@xxxxxxxxx> wrote: > tree: https://github.com/awilliam/linux-vfio.git mdev-v14 > head: 4e00cd8f5f2bb527739c118ecef7618cba91ad8f > commit: 08328e6c0af2193e06343641ab48efa95bcd9e24 [11/22] vfio iommu: Add blocking notifier to notify DMA_UNMAP > config: x86_64-randconfig-s2-11171425 (attached as .config) > compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901 > reproduce: > git checkout 08328e6c0af2193e06343641ab48efa95bcd9e24 > # 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 >>): > > In file included from include/uapi/linux/stddef.h:1:0, > from include/linux/stddef.h:4, > from include/uapi/linux/posix_types.h:4, > from include/uapi/linux/types.h:13, > from include/linux/types.h:5, > from include/linux/compat.h:8, > from drivers/vfio/vfio_iommu_type1.c:27: > drivers/vfio/vfio_iommu_type1.c: In function 'vfio_iommu_type1_ioctl': > >> include/linux/compiler.h:125:12: warning: 'retries' may be used uninitialized in this function [-Wmaybe-uninitialized] > ______r = likely_notrace(x); \ > ^ > drivers/vfio/vfio_iommu_type1.c:784:15: note: 'retries' was declared here > int ret = 0, retries; > ^~~~~~~ Sort of impossible since retries is initialized when (dma != dma_last), where dma_last is initialized to NULL, but I'll go ahead and add a zero initializer to retries to make this happy. Thanks, Alex > > vim +/retries +125 include/linux/compiler.h > > d9ad8bc0 Bart Van Assche 2009-04-05 109 && !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__) > 2ed84eeb Steven Rostedt 2008-11-12 110 void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); > 1f0d69a9 Steven Rostedt 2008-11-12 111 > 1f0d69a9 Steven Rostedt 2008-11-12 112 #define likely_notrace(x) __builtin_expect(!!(x), 1) > 1f0d69a9 Steven Rostedt 2008-11-12 113 #define unlikely_notrace(x) __builtin_expect(!!(x), 0) > 1f0d69a9 Steven Rostedt 2008-11-12 114 > 45b79749 Steven Rostedt 2008-11-21 115 #define __branch_check__(x, expect) ({ \ > 1f0d69a9 Steven Rostedt 2008-11-12 116 int ______r; \ > 2ed84eeb Steven Rostedt 2008-11-12 117 static struct ftrace_branch_data \ > 1f0d69a9 Steven Rostedt 2008-11-12 118 __attribute__((__aligned__(4))) \ > 45b79749 Steven Rostedt 2008-11-21 119 __attribute__((section("_ftrace_annotated_branch"))) \ > 1f0d69a9 Steven Rostedt 2008-11-12 120 ______f = { \ > 1f0d69a9 Steven Rostedt 2008-11-12 121 .func = __func__, \ > 1f0d69a9 Steven Rostedt 2008-11-12 122 .file = __FILE__, \ > 1f0d69a9 Steven Rostedt 2008-11-12 123 .line = __LINE__, \ > 1f0d69a9 Steven Rostedt 2008-11-12 124 }; \ > 1f0d69a9 Steven Rostedt 2008-11-12 @125 ______r = likely_notrace(x); \ > 45b79749 Steven Rostedt 2008-11-21 126 ftrace_likely_update(&______f, ______r, expect); \ > 1f0d69a9 Steven Rostedt 2008-11-12 127 ______r; \ > 1f0d69a9 Steven Rostedt 2008-11-12 128 }) > 1f0d69a9 Steven Rostedt 2008-11-12 129 > 1f0d69a9 Steven Rostedt 2008-11-12 130 /* > 1f0d69a9 Steven Rostedt 2008-11-12 131 * Using __builtin_constant_p(x) to ignore cases where the return > 1f0d69a9 Steven Rostedt 2008-11-12 132 * value is always the same. This idea is taken from a similar patch > 1f0d69a9 Steven Rostedt 2008-11-12 133 * written by Daniel Walker. > > :::::: The code at line 125 was first introduced by commit > :::::: 1f0d69a9fc815db82f15722bf05227190b1d714d tracing: profile likely and unlikely annotations > > :::::: TO: Steven Rostedt <rostedt@xxxxxxxxxxx> > :::::: CC: Ingo Molnar <mingo@xxxxxxx> > > --- > 0-DAY kernel test infrastructure Open Source Technology Center > https://lists.01.org/pipermail/kbuild-all Intel Corporation -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
