4:22 a.m.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
linux-5.13.y-rt-testing
head: cdfc6ae55ef52147859af8c8a9f82c4858eed749
commit: 4b788a578cc2be37f1761f07407a9d920ecb0671 [10/227] printk: introduce kernel sync
mode
config: m68k-randconfig-r005-20210712 (attached as .config)
compiler: m68k-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-5.13.y-rt-testing
git checkout 4b788a578cc2be37f1761f07407a9d920ecb0671
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp(a)intel.com>
All errors (new ones prefixed by >>):
kernel/printk/printk.c:177:5: warning: no previous prototype for
'devkmsg_sysctl_set_loglvl' [-Wmissing-prototypes]
177 | int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write,
| ^~~~~~~~~~~~~~~~~~~~~~~~~
kernel/printk/printk.c:2428:2: error: #error FIXME
2428 | #error FIXME
| ^~~~~
kernel/printk/printk.c: In function 'console_unlock':
> kernel/printk/printk.c:2790:9: error: implicit declaration of
function 'read_console_seq'; did you mean 'up_console_sem'?
[-Werror=implicit-function-declaration]
2790 | seq = read_console_seq();
| ^~~~~~~~~~~~~~~~
| up_console_sem
kernel/printk/printk.c:2796:4: error: implicit declaration of function
'latched_seq_write' [-Werror=implicit-function-declaration]
2796 | latched_seq_write(&console_seq, r.info->seq);
| ^~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
vim +2790 kernel/printk/printk.c
2724
2725 /**
2726 * console_unlock - unlock the console system
2727 *
2728 * Releases the console_lock which the caller holds on the console system
2729 * and the console driver list.
2730 *
2731 * While the console_lock was held, console output may have been buffered
2732 * by printk(). If this is the case, console_unlock(); emits
2733 * the output prior to releasing the lock.
2734 *
2735 * If there is output waiting, we wake /dev/kmsg and syslog() users.
2736 *
2737 * console_unlock(); may be called from any context.
2738 */
2739 void console_unlock(void)
2740 {
2741 static char ext_text[CONSOLE_EXT_LOG_MAX];
2742 static char text[CONSOLE_LOG_MAX];
2743 unsigned long flags;
2744 bool do_cond_resched, retry;
2745 struct printk_info info;
2746 struct printk_record r;
2747 u64 seq;
2748
2749 if (console_suspended) {
2750 up_console_sem();
2751 return;
2752 }
2753
2754 prb_rec_init_rd(&r, &info, text, sizeof(text));
2755
2756 /*
2757 * Console drivers are called with interrupts disabled, so
2758 * @console_may_schedule should be cleared before; however, we may
2759 * end up dumping a lot of lines, for example, if called from
2760 * console registration path, and should invoke cond_resched()
2761 * between lines if allowable. Not doing so can cause a very long
2762 * scheduling stall on a slow console leading to RCU stall and
2763 * softlockup warnings which exacerbate the issue with more
2764 * messages practically incapacitating the system.
2765 *
2766 * console_trylock() is not able to detect the preemptive
2767 * context reliably. Therefore the value must be stored before
2768 * and cleared after the "again" goto label.
2769 */
2770 do_cond_resched = console_may_schedule;
2771 again:
2772 console_may_schedule = 0;
2773
2774 /*
2775 * We released the console_sem lock, so we need to recheck if
2776 * cpu is online and (if not) is there at least one CON_ANYTIME
2777 * console.
2778 */
2779 if (!can_use_console()) {
2780 console_locked = 0;
2781 up_console_sem();
2782 return;
2783 }
2784
2785 for (;;) {
2786 size_t ext_len = 0;
2787 size_t len;
2788
2789 skip:
2790 seq = read_console_seq();
2791 if
(!prb_read_valid(prb, seq, &r))
2792 break;
2793
2794 if (seq != r.info->seq) {
2795 console_dropped += r.info->seq - seq;
2796 latched_seq_write(&console_seq, r.info->seq);
2797 seq = r.info->seq;
2798 }
2799
2800 if (suppress_message_printing(r.info->level)) {
2801 /*
2802 * Skip record we have buffered and already printed
2803 * directly to the console when we received it, and
2804 * record that has level above the console loglevel.
2805 */
2806 latched_seq_write(&console_seq, seq + 1);
2807 goto skip;
2808 }
2809
2810 /* Output to all consoles once old messages replayed. */
2811 if (unlikely(exclusive_console &&
2812 seq >= exclusive_console_stop_seq)) {
2813 exclusive_console = NULL;
2814 }
2815
2816 /*
2817 * Handle extended console text first because later
2818 * record_print_text() will modify the record buffer in-place.
2819 */
2820 if (nr_ext_console_drivers) {
2821 ext_len = info_print_ext_header(ext_text,
2822 sizeof(ext_text),
2823 r.info);
2824 ext_len += msg_print_ext_body(ext_text + ext_len,
2825 sizeof(ext_text) - ext_len,
2826 &r.text_buf[0],
2827 r.info->text_len,
2828 &r.info->dev_info);
2829 }
2830 len = record_print_text(&r,
2831 console_msg_format & MSG_FORMAT_SYSLOG,
2832 printk_time);
2833 latched_seq_write(&console_seq, seq + 1);
2834
2835 printk_safe_enter_irqsave(flags);
2836
2837 /*
2838 * While actively printing out messages, if another printk()
2839 * were to occur on another CPU, it may wait for this one to
2840 * finish. This task can not be preempted if there is a
2841 * waiter waiting to take over.
2842 */
2843 console_lock_spinning_enable();
2844
2845 stop_critical_timings(); /* don't trace print latency */
2846 call_console_drivers(ext_text, ext_len, text, len);
2847 start_critical_timings();
2848
2849 if (console_lock_spinning_disable_and_check()) {
2850 printk_safe_exit_irqrestore(flags);
2851 return;
2852 }
2853
2854 printk_safe_exit_irqrestore(flags);
2855
2856 if (do_cond_resched)
2857 cond_resched();
2858 }
2859
2860 console_locked = 0;
2861
2862 up_console_sem();
2863
2864 /*
2865 * Someone could have filled up the buffer again, so re-check if there's
2866 * something to flush. In case we cannot trylock the console_sem again,
2867 * there's a new owner and the console_unlock() from them will do the
2868 * flush, no worries.
2869 */
2870 retry = prb_read_valid(prb, read_console_seq(), NULL);
2871 if (retry && console_trylock())
2872 goto again;
2873 }
2874 EXPORT_SYMBOL(console_unlock);
2875
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org