tree: https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-5.10.y-rt-rebase head: 87b7b3d2cb296950a0e3005406899ccfbbc9da7c commit: ca4fcaa60de914c0ef6864983a8488bf5ab6cafb [57/209] printk: move console printing to kthreads config: ia64-allnoconfig (attached as .config) compiler: ia64-linux-gcc (GCC) 9.3.0 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://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/com... git remote add linux-rt-devel https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git git fetch --no-tags linux-rt-devel linux-5.10.y-rt-rebase git checkout ca4fcaa60de914c0ef6864983a8488bf5ab6cafb # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=ia64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): In file included from arch/ia64/include/asm/pgtable.h:154, from include/linux/pgtable.h:6, from include/linux/mm.h:33, from kernel/printk/printk.c:23: arch/ia64/include/asm/mmu_context.h: In function 'reload_context': arch/ia64/include/asm/mmu_context.h:137:41: warning: variable 'old_rr4' set but not used [-Wunused-but-set-variable] 137 | unsigned long rr0, rr1, rr2, rr3, rr4, old_rr4; | ^~~~~~~ In file included from kernel/printk/printk.c:63: kernel/printk/internal.h: At top level: kernel/printk/internal.h:56:20: warning: no previous prototype for 'vprintk_func' [-Wmissing-prototypes] 56 | __printf(1, 0) int vprintk_func(const char *fmt, va_list args) { return 0; } | ^~~~~~~~~~~~ kernel/printk/printk.c:180:5: warning: no previous prototype for 'devkmsg_sysctl_set_loglvl' [-Wmissing-prototypes] 180 | int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, | ^~~~~~~~~~~~~~~~~~~~~~~~~ In file included from ./arch/ia64/include/generated/asm/rwonce.h:1, from include/linux/compiler.h:232, from include/linux/kernel.h:11, from kernel/printk/printk.c:22: kernel/printk/printk.c: In function 'register_console': 2677 | atomic64_set(&newcon->printk_seq, prb_next_seq(prb)); | ^~~ include/asm-generic/rwonce.h:55:33: note: in definition of macro '__WRITE_ONCE' 55 | *(volatile typeof(x) *)&(x) = (val); \ | ^~~ arch/ia64/include/asm/atomic.h:28:27: note: in expansion of macro 'WRITE_ONCE' 28 | #define atomic64_set(v,i) WRITE_ONCE(((v)->counter), (i)) | ^~~~~~~~~~ kernel/printk/printk.c:2677:3: note: in expansion of macro 'atomic64_set' 2677 | atomic64_set(&newcon->printk_seq, prb_next_seq(prb)); | ^~~~~~~~~~~~ kernel/printk/printk.c:2677:50: note: each undeclared identifier is reported only once for each function it appears in 2677 | atomic64_set(&newcon->printk_seq, prb_next_seq(prb)); | ^~~ include/asm-generic/rwonce.h:55:33: note: in definition of macro '__WRITE_ONCE' 55 | *(volatile typeof(x) *)&(x) = (val); \ | ^~~ arch/ia64/include/asm/atomic.h:28:27: note: in expansion of macro 'WRITE_ONCE' 28 | #define atomic64_set(v,i) WRITE_ONCE(((v)->counter), (i)) | ^~~~~~~~~~ kernel/printk/printk.c:2677:3: note: in expansion of macro 'atomic64_set' 2677 | atomic64_set(&newcon->printk_seq, prb_next_seq(prb)); | ^~~~~~~~~~~~ In file included from include/linux/mmzone.h:10, from include/linux/gfp.h:6, from include/linux/mm.h:10, from kernel/printk/printk.c:23: kernel/printk/printk.c: In function 'printk_kthread_func': 2836 | error = wait_event_interruptible(log_wait, | ^~~~~~~~ include/linux/wait.h:272:39: note: in definition of macro '___wait_event' 272 | long __int = prepare_to_wait_event(&wq_head, &__wq_entry, state);\ | ^~~~~~~ include/linux/wait.h:465:11: note: in expansion of macro '__wait_event_interruptible' 465 | __ret = __wait_event_interruptible(wq_head, condition); \ | ^~~~~~~~~~~~~~~~~~~~~~~~~~ kernel/printk/printk.c:2836:11: note: in expansion of macro 'wait_event_interruptible' 2836 | error = wait_event_interruptible(log_wait, | ^~~~~~~~~~~~~~~~~~~~~~~~ kernel/printk/printk.c:2877:7: error: implicit declaration of function 'kernel_sync_mode' [-Werror=implicit-function-declaration] 2877 | if (kernel_sync_mode() && con->write_atomic) { | ^~~~~~~~~~~~~~~~ 2889 | printk_delay(r.info->level); | ^~~~~~~~~~~~ | print_dev_t kernel/printk/printk.c: In function 'console_try_thread': 2938 | buf = get_sprint_buf(&sprint_id, &irqflags); | ^~~~~~~~~~~~~~ kernel/printk/printk.c:2938:6: warning: assignment to 'char *' from 'int' makes pointer from integer without a cast [-Wint-conversion] 2938 | buf = get_sprint_buf(&sprint_id, &irqflags); | ^ 2942 | print_sync_until(prb_next_seq(prb), con, buf, PREFIX_MAX + LOG_LINE_MAX); | ^~~~~~~~~~~~~~~~ kernel/printk/printk.c:2942:32: error: 'prb' undeclared (first use in this function) 2942 | print_sync_until(prb_next_seq(prb), con, buf, PREFIX_MAX + LOG_LINE_MAX); | ^~~ 2944 | put_sprint_buf(sprint_id, irqflags); | ^~~~~~~~~~~~~~ kernel/printk/printk.c: At top level: kernel/printk/printk.c:3483:6: warning: no previous prototype for 'prb_lock' [-Wmissing-prototypes] 3483 | void prb_lock(struct prb_cpulock *cpu_lock, unsigned int *cpu_store) | ^~~~~~~~ kernel/printk/printk.c:3501:6: warning: no previous prototype for 'prb_unlock' [-Wmissing-prototypes] 3501 | void prb_unlock(struct prb_cpulock *cpu_lock, unsigned int cpu_store) | ^~~~~~~~~~ kernel/printk/printk.c:2094:13: warning: 'call_console_drivers' defined but not used [-Wunused-function] 2094 | static void call_console_drivers(const char *ext_text, size_t ext_len, | ^~~~~~~~~~~~~~~~~~~~ kernel/printk/printk.c:2079:12: warning: 'syslog_seq' defined but not used [-Wunused-variable] 2079 | static u64 syslog_seq; | ^~~~~~~~~~ kernel/printk/printk.c:84:13: warning: 'sync_mode' defined but not used [-Wunused-variable] 84 | static bool sync_mode; | ^~~~~~~~~ cc1: some warnings being treated as errors vim +/prb +2677 kernel/printk/printk.c 2563 2564 /* 2565 * The console driver calls this routine during kernel initialization 2566 * to register the console printing procedure with printk() and to 2567 * print any messages that were printed by the kernel before the 2568 * console driver was initialized. 2569 * 2570 * This can happen pretty early during the boot process (because of 2571 * early_printk) - sometimes before setup_arch() completes - be careful 2572 * of what kernel features are used - they may not be initialised yet. 2573 * 2574 * There are two types of consoles - bootconsoles (early_printk) and 2575 * "real" consoles (everything which is not a bootconsole) which are 2576 * handled differently. 2577 * - Any number of bootconsoles can be registered at any time. 2578 * - As soon as a "real" console is registered, all bootconsoles 2579 * will be unregistered automatically. 2580 * - Once a "real" console is registered, any attempt to register a 2581 * bootconsoles will be rejected 2582 */ 2583 void register_console(struct console *newcon) 2584 { 2585 struct console *bcon = NULL; 2586 int err; 2587 2588 for_each_console(bcon) { 2589 if (WARN(bcon == newcon, "console '%s%d' already registered\n", 2590 bcon->name, bcon->index)) 2591 return; 2592 } 2593 2594 /* 2595 * before we register a new CON_BOOT console, make sure we don't 2596 * already have a valid console 2597 */ 2598 if (newcon->flags & CON_BOOT) { 2599 for_each_console(bcon) { 2600 if (!(bcon->flags & CON_BOOT)) { 2601 pr_info("Too late to register bootconsole %s%d\n", 2602 newcon->name, newcon->index); 2603 return; 2604 } 2605 } 2606 } 2607 2608 newcon->thread = NULL; 2609 2610 if (console_drivers && console_drivers->flags & CON_BOOT) 2611 bcon = console_drivers; 2612 2613 if (!has_preferred_console || bcon || !console_drivers) 2614 has_preferred_console = preferred_console >= 0; 2615 2616 /* 2617 * See if we want to use this console driver. If we 2618 * didn't select a console we take the first one 2619 * that registers here. 2620 */ 2621 if (!has_preferred_console) { 2622 if (newcon->index < 0) 2623 newcon->index = 0; 2624 if (newcon->setup == NULL || 2625 newcon->setup(newcon, NULL) == 0) { 2626 newcon->flags |= CON_ENABLED; 2627 if (newcon->device) { 2628 newcon->flags |= CON_CONSDEV; 2629 has_preferred_console = true; 2630 } 2631 } 2632 } 2633 2634 /* See if this console matches one we selected on the command line */ 2635 err = try_enable_new_console(newcon, true); 2636 2637 /* If not, try to match against the platform default(s) */ 2638 if (err == -ENOENT) 2639 err = try_enable_new_console(newcon, false); 2640 2641 /* printk() messages are not printed to the Braille console. */ 2642 if (err || newcon->flags & CON_BRL) 2643 return; 2644 2645 /* 2646 * If we have a bootconsole, and are switching to a real console, 2647 * don't print everything out again, since when the boot console, and 2648 * the real console are the same physical device, it's annoying to 2649 * see the beginning boot messages twice 2650 */ 2651 if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) 2652 newcon->flags &= ~CON_PRINTBUFFER; 2653 2654 /* 2655 * Put this console in the list - keep the 2656 * preferred driver at the head of the list. 2657 */ 2658 console_lock(); 2659 if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { 2660 newcon->next = console_drivers; 2661 console_drivers = newcon; 2662 if (newcon->next) 2663 newcon->next->flags &= ~CON_CONSDEV; 2664 /* Ensure this flag is always set for the head of the list */ 2665 newcon->flags |= CON_CONSDEV; 2666 } else { 2667 newcon->next = console_drivers->next; 2668 console_drivers->next = newcon; 2669 } 2670 2671 if (newcon->flags & CON_EXTENDED) 2672 nr_ext_console_drivers++; 2673 2674 if (newcon->flags & CON_PRINTBUFFER) 2675 atomic64_set(&newcon->printk_seq, 0); 2676 else 2678 2679 console_try_thread(newcon); 2680 console_unlock(); 2681 console_sysfs_notify(); 2682 2683 /* 2684 * By unregistering the bootconsoles after we enable the real console 2685 * we get the "console xxx enabled" message on all the consoles - 2686 * boot consoles, real consoles, etc - this is to ensure that end 2687 * users know there might be something in the kernel's log buffer that 2688 * went to the bootconsole (that they do not see on the real console) 2689 */ 2690 pr_info("%sconsole [%s%d] enabled\n", 2691 (newcon->flags & CON_BOOT) ? "boot" : "" , 2692 newcon->name, newcon->index); 2693 if (bcon && 2694 ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && 2695 !keep_bootcon) { 2696 /* We need to iterate through all boot consoles, to make 2697 * sure we print everything out, before we unregister them. 2698 */ 2699 for_each_console(bcon) 2700 if (bcon->flags & CON_BOOT) 2701 unregister_console(bcon); 2702 } 2703 } 2704 EXPORT_SYMBOL(register_console); 2705 2706 int unregister_console(struct console *console) 2707 { 2708 struct console *con; 2709 int res; 2710 2711 pr_info("%sconsole [%s%d] disabled\n", 2712 (console->flags & CON_BOOT) ? "boot" : "" , 2713 console->name, console->index); 2714 2715 res = _braille_unregister_console(console); 2716 if (res < 0) 2717 return res; 2718 if (res > 0) 2719 return 0; 2720 2721 res = -ENODEV; 2722 console_lock(); 2723 if (console_drivers == console) { 2724 console_drivers=console->next; 2725 res = 0; 2726 } else { 2727 for_each_console(con) { 2728 if (con->next == console) { 2729 con->next = console->next; 2730 res = 0; 2731 break; 2732 } 2733 } 2734 } 2735 2736 if (res) 2737 goto out_disable_unlock; 2738 2739 if (console->flags & CON_EXTENDED) 2740 nr_ext_console_drivers--; 2741 2742 /* 2743 * If this isn't the last console and it has CON_CONSDEV set, we 2744 * need to set it on the next preferred console. 2745 */ 2746 if (console_drivers != NULL && console->flags & CON_CONSDEV) 2747 console_drivers->flags |= CON_CONSDEV; 2748 2749 console->flags &= ~CON_ENABLED; 2750 console_unlock(); 2751 console_sysfs_notify(); 2752 2753 if (console->thread && !IS_ERR(console->thread)) 2754 kthread_stop(console->thread); 2755 2756 if (console->exit) 2757 res = console->exit(console); 2758 2759 return res; 2760 2761 out_disable_unlock: 2762 console->flags &= ~CON_ENABLED; 2763 console_unlock(); 2764 2765 return res; 2766 } 2767 EXPORT_SYMBOL(unregister_console); 2768 2769 /* 2770 * Initialize the console device. This is called *early*, so 2771 * we can't necessarily depend on lots of kernel help here. 2772 * Just do some early initializations, and do the complex setup 2773 * later. 2774 */ 2775 void __init console_init(void) 2776 { 2777 int ret; 2778 initcall_t call; 2779 initcall_entry_t *ce; 2780 2781 /* Setup the default TTY line discipline. */ 2782 n_tty_init(); 2783 2784 /* 2785 * set up the console device so that later boot sequences can 2786 * inform about problems etc.. 2787 */ 2788 ce = __con_initcall_start; 2789 trace_initcall_level("console"); 2790 while (ce < __con_initcall_end) { 2791 call = initcall_from_entry(ce); 2792 trace_initcall_start(call); 2793 ret = call(); 2794 trace_initcall_finish(call, ret); 2795 ce++; 2796 } 2797 } 2798 2799 static int printk_kthread_func(void *data) 2800 { 2801 struct console *con = data; 2802 unsigned long dropped = 0; 2803 struct printk_info info; 2804 struct printk_record r; 2805 char *ext_text = NULL; 2806 size_t dropped_len; 2807 char *dropped_text; 2808 int ret = -ENOMEM; 2809 char *write_text; 2810 u64 printk_seq; 2811 size_t len; 2812 char *text; 2813 int error; 2814 u64 seq; 2815 2816 if (con->flags & CON_EXTENDED) { 2817 ext_text = kmalloc(CONSOLE_EXT_LOG_MAX, GFP_KERNEL); 2818 if (!ext_text) 2819 return ret; 2820 } 2821 text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); 2822 dropped_text = kmalloc(64, GFP_KERNEL); 2823 if (!text || !dropped_text) 2824 goto out; 2825 2826 if (con->flags & CON_EXTENDED) 2827 write_text = ext_text; 2828 else 2829 write_text = text; 2830 2831 seq = atomic64_read(&con->printk_seq); 2832 2833 prb_rec_init_rd(&r, &info, text, LOG_LINE_MAX + PREFIX_MAX); 2834 2835 for (;;) { 2837 prb_read_valid(prb, seq, &r) || kthread_should_stop()); 2838 2839 if (kthread_should_stop()) 2840 break; 2841 2842 if (error) 2843 continue; 2844 2845 if (seq != r.info->seq) { 2846 dropped += r.info->seq - seq; 2847 seq = r.info->seq; 2848 } 2849 2850 seq++; 2851 2852 if (!(con->flags & CON_ENABLED)) 2853 continue; 2854 2855 if (suppress_message_printing(r.info->level)) 2856 continue; 2857 2858 if (con->flags & CON_EXTENDED) { 2859 len = info_print_ext_header(ext_text, 2860 CONSOLE_EXT_LOG_MAX, 2861 r.info); 2862 len += msg_print_ext_body(ext_text + len, 2863 CONSOLE_EXT_LOG_MAX - len, 2864 &r.text_buf[0], r.info->text_len, 2865 &r.info->dev_info); 2866 } else { 2867 len = record_print_text(&r, 2868 console_msg_format & MSG_FORMAT_SYSLOG, 2869 printk_time); 2870 } 2871 2872 printk_seq = atomic64_read(&con->printk_seq); 2873 2874 console_lock(); 2875 console_may_schedule = 0; 2876 2877 if (kernel_sync_mode() && con->write_atomic) { 2878 console_unlock(); 2879 break; 2880 } 2881 2882 if (!(con->flags & CON_EXTENDED) && dropped) { 2883 dropped_len = snprintf(dropped_text, 64, 2884 "** %lu printk messages dropped **\n", 2885 dropped); 2886 dropped = 0; 2887 2888 con->write(con, dropped_text, dropped_len); 2889 printk_delay(r.info->level); 2890 } 2891 2892 con->write(con, write_text, len); 2893 if (len) 2894 printk_delay(r.info->level); 2895 2896 atomic64_cmpxchg_relaxed(&con->printk_seq, printk_seq, seq); 2897 2898 console_unlock(); 2899 } 2900 out: 2901 kfree(dropped_text); 2902 kfree(text); 2903 kfree(ext_text); 2904 pr_info("%sconsole [%s%d]: printing thread stopped\n", 2905 (con->flags & CON_BOOT) ? "boot" : "" , 2906 con->name, con->index); 2907 return ret; 2908 } 2909 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org