Hi Sebastian, [FYI, it's a private test report for your RFC patch.] [auto build test WARNING on next-20201215] [cannot apply to tip/perf/core linux/master block/for-next trace/for-next linus/master v5.10 v5.10-rc7 v5.10-rc6 v5.10] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Sebastian-Andrzej-Siewior/tracin... base: 9317f948b0b188b8d2fded75957e6d42c460df1b config: i386-randconfig-a001-20201216 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 reproduce (this is a W=1 build): # https://github.com/0day-ci/linux/commit/afd5d9090ab105dae5830c2f050a30ec3... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Sebastian-Andrzej-Siewior/tracing-Merge-irqflags-preemt-counter-add-RT-bits/20201217-012430 git checkout afd5d9090ab105dae5830c2f050a30ec306d7201 # save the attached .config to linux build tree make W=1 ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): kernel/trace/trace.c: In function '__trace_puts': 1001 | int pc; | ^~ kernel/trace/trace.c: In function '__trace_bputs': kernel/trace/trace.c:1056:6: warning: variable 'pc' set but not used [-Wunused-but-set-variable] 1056 | int pc; | ^~ vim +/pc +1001 kernel/trace/trace.c 52ffabe3848a1eb Steven Rostedt (Red Hat 2016-11-23 987) 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 988) /** 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 989) * __trace_puts - write a constant string into the trace buffer. 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 990) * @ip: The address of the caller 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 991) * @str: The constant string to write 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 992) * @size: The size of the string. 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 993) */ 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 994) int __trace_puts(unsigned long ip, const char *str, int size) 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 995) { 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 996) struct ring_buffer_event *event; 13292494379f92f Steven Rostedt (VMware 2019-12-13 997) struct trace_buffer *buffer; 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 998) struct print_entry *entry; afd5d9090ab105d Sebastian Andrzej Siewior 2020-12-16 999 unsigned int trace_ctx; 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1000) int alloc; 8abfb8727f4a724 zhangwei(Jovi 2013-07-18 @1001) int pc; 8abfb8727f4a724 zhangwei(Jovi 2013-07-18 1002) 983f938ae695852 Steven Rostedt (Red Hat 2015-09-30 1003) if (!(global_trace.trace_flags & TRACE_ITER_PRINTK)) f0160a5a2912267 zhangwei(Jovi 2013-07-18 1004) return 0; f0160a5a2912267 zhangwei(Jovi 2013-07-18 1005) 8abfb8727f4a724 zhangwei(Jovi 2013-07-18 1006) pc = preempt_count(); 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1007) 3132e107d608f87 Steven Rostedt (Red Hat 2014-01-23 1008) if (unlikely(tracing_selftest_running || tracing_disabled)) 3132e107d608f87 Steven Rostedt (Red Hat 2014-01-23 1009) return 0; 3132e107d608f87 Steven Rostedt (Red Hat 2014-01-23 1010) 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1011) alloc = sizeof(*entry) + size + 2; /* possible \n added */ 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1012) afd5d9090ab105d Sebastian Andrzej Siewior 2020-12-16 1013 trace_ctx = tracing_gen_ctx_flags(); 1c5eb4481e0151d Steven Rostedt (VMware 2020-01-09 1014) buffer = global_trace.array_buffer.buffer; 82d1b8158c9a77c Steven Rostedt (VMware 2020-01-16 1015) ring_buffer_nest_start(buffer); 3e9a8aadca4807b Steven Rostedt (Red Hat 2016-11-23 1016) event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, afd5d9090ab105d Sebastian Andrzej Siewior 2020-12-16 1017 trace_ctx); 82d1b8158c9a77c Steven Rostedt (VMware 2020-01-16 1018) if (!event) { 82d1b8158c9a77c Steven Rostedt (VMware 2020-01-16 1019) size = 0; 82d1b8158c9a77c Steven Rostedt (VMware 2020-01-16 1020) goto out; 82d1b8158c9a77c Steven Rostedt (VMware 2020-01-16 1021) } 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1022) 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1023) entry = ring_buffer_event_data(event); 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1024) entry->ip = ip; 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1025) 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1026) memcpy(&entry->buf, str, size); 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1027) 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1028) /* Add a newline if necessary */ 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1029) if (entry->buf[size - 1] != '\n') { 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1030) entry->buf[size] = '\n'; 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1031) entry->buf[size + 1] = '\0'; 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1032) } else 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1033) entry->buf[size] = '\0'; 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1034) 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1035) __buffer_unlock_commit(buffer, event); afd5d9090ab105d Sebastian Andrzej Siewior 2020-12-16 1036 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL); 82d1b8158c9a77c Steven Rostedt (VMware 2020-01-16 1037) out: 82d1b8158c9a77c Steven Rostedt (VMware 2020-01-16 1038) ring_buffer_nest_end(buffer); 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1039) return size; 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1040) } 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1041) EXPORT_SYMBOL_GPL(__trace_puts); 09ae72348eccb60 Steven Rostedt (Red Hat 2013-03-08 1042) --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org