Hi Steven, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on rostedt-trace/for-next] [also build test WARNING on linux/master hnaz-mm/master linus/master v5.16-rc3 next-20211129] [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/Steven-Rostedt/tracing-Various-updates/20211130-104342 base: https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git for-next config: mips-allyesconfig (https://download.01.org/0day-ci/archive/20211130/202111301209.GarWNR3z-lkp@xxxxxxxxx/config) compiler: mips-linux-gcc (GCC) 11.2.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/0day-ci/linux/commit/1ac91c8764ae50601cd41dceb620205607ab59f6 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Steven-Rostedt/tracing-Various-updates/20211130-104342 git checkout 1ac91c8764ae50601cd41dceb620205607ab59f6 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=mips SHELL=/bin/bash kernel/trace/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> All warnings (new ones prefixed by >>): kernel/trace/trace.c: In function 'trace_event_buffer_lock_reserve': >> kernel/trace/trace.c:2769:21: warning: suggest parentheses around assignment used as truth value [-Wparentheses] 2769 | if (entry = __this_cpu_read(trace_buffered_event)) { | ^~~~~ kernel/trace/trace.c: In function 'trace_check_vprintf': kernel/trace/trace.c:3820:17: warning: function 'trace_check_vprintf' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format] 3820 | trace_seq_vprintf(&iter->seq, iter->fmt, ap); | ^~~~~~~~~~~~~~~~~ kernel/trace/trace.c:3887:17: warning: function 'trace_check_vprintf' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format] 3887 | trace_seq_vprintf(&iter->seq, p, ap); | ^~~~~~~~~~~~~~~~~ vim +2769 kernel/trace/trace.c 2736 2737 struct ring_buffer_event * 2738 trace_event_buffer_lock_reserve(struct trace_buffer **current_rb, 2739 struct trace_event_file *trace_file, 2740 int type, unsigned long len, 2741 unsigned int trace_ctx) 2742 { 2743 struct ring_buffer_event *entry; 2744 struct trace_array *tr = trace_file->tr; 2745 int val; 2746 2747 *current_rb = tr->array_buffer.buffer; 2748 2749 if (!tr->no_filter_buffering_ref && 2750 (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED))) { 2751 preempt_disable_notrace(); 2752 /* 2753 * Filtering is on, so try to use the per cpu buffer first. 2754 * This buffer will simulate a ring_buffer_event, 2755 * where the type_len is zero and the array[0] will 2756 * hold the full length. 2757 * (see include/linux/ring-buffer.h for details on 2758 * how the ring_buffer_event is structured). 2759 * 2760 * Using a temp buffer during filtering and copying it 2761 * on a matched filter is quicker than writing directly 2762 * into the ring buffer and then discarding it when 2763 * it doesn't match. That is because the discard 2764 * requires several atomic operations to get right. 2765 * Copying on match and doing nothing on a failed match 2766 * is still quicker than no copy on match, but having 2767 * to discard out of the ring buffer on a failed match. 2768 */ > 2769 if (entry = __this_cpu_read(trace_buffered_event)) { 2770 int max_len = PAGE_SIZE - struct_size(entry, array, 1); 2771 2772 val = this_cpu_inc_return(trace_buffered_event_cnt); 2773 2774 /* 2775 * Preemption is disabled, but interrupts and NMIs 2776 * can still come in now. If that happens after 2777 * the above increment, then it will have to go 2778 * back to the old method of allocating the event 2779 * on the ring buffer, and if the filter fails, it 2780 * will have to call ring_buffer_discard_commit() 2781 * to remove it. 2782 * 2783 * Need to also check the unlikely case that the 2784 * length is bigger than the temp buffer size. 2785 * If that happens, then the reserve is pretty much 2786 * guaranteed to fail, as the ring buffer currently 2787 * only allows events less than a page. But that may 2788 * change in the future, so let the ring buffer reserve 2789 * handle the failure in that case. 2790 */ 2791 if (val == 1 && likely(len <= max_len)) { 2792 trace_event_setup(entry, type, trace_ctx); 2793 entry->array[0] = len; 2794 /* Return with preemption disabled */ 2795 return entry; 2796 } 2797 this_cpu_dec(trace_buffered_event_cnt); 2798 } 2799 /* __trace_buffer_lock_reserve() disables preemption */ 2800 preempt_enable_notrace(); 2801 } 2802 2803 entry = __trace_buffer_lock_reserve(*current_rb, type, len, 2804 trace_ctx); 2805 /* 2806 * If tracing is off, but we have triggers enabled 2807 * we still need to look at the event data. Use the temp_buffer 2808 * to store the trace event for the trigger to use. It's recursive 2809 * safe and will not be recorded anywhere. 2810 */ 2811 if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) { 2812 *current_rb = temp_buffer; 2813 entry = __trace_buffer_lock_reserve(*current_rb, type, len, 2814 trace_ctx); 2815 } 2816 return entry; 2817 } 2818 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve); 2819 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
