tree: https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-5.16.y-rt-rebase head: 1722f531f5244c70dcd9687c40729860bb254e8d commit: 75ade2af49f22287257530b6ba838efe2b6dfb56 [8/132] printk: refactor and rework printing logic config: hexagon-buildonly-randconfig-r005-20220121 (https://download.01.org/0day-ci/archive/20220122/202201220904.ZcTeNwWl-lk...) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 7b3d30728816403d1fd73cc5082e9fb761262bce) 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 rt-devel https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git git fetch --no-tags rt-devel linux-5.16.y-rt-rebase git checkout 75ade2af49f22287257530b6ba838efe2b6dfb56 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash kernel/printk/ 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 >>): kernel/printk/printk.c:175:5: warning: no previous prototype for function 'devkmsg_sysctl_set_loglvl' [-Wmissing-prototypes] int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, ^ kernel/printk/printk.c:175:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, ^ static boot_delay_msec(r.info->level); ^ printk_delay(); ^ 1 warning and 2 errors generated. vim +/boot_delay_msec +2628 kernel/printk/printk.c 2556 2557 /* 2558 * Print one record for the given console. The record printed is whatever 2559 * record is the next available record for the given console. 2560 * 2561 * Requires the console_lock. 2562 * 2563 * Returns false if the given console has no next record to print, otherwise 2564 * true. 2565 * 2566 * @handover will be set to true if a printk waiter has taken over the 2567 * console_lock, in which case the caller is no longer holding the 2568 * console_lock. 2569 */ 2570 static bool console_emit_next_record(struct console *con, bool *handover) 2571 { 2572 static char ext_text[CONSOLE_EXT_LOG_MAX]; 2573 static char text[CONSOLE_LOG_MAX]; 2574 struct printk_info info; 2575 struct printk_record r; 2576 unsigned long flags; 2577 char *write_text; 2578 size_t len; 2579 2580 prb_rec_init_rd(&r, &info, text, sizeof(text)); 2581 2582 if (!prb_read_valid(prb, con->seq, &r)) 2583 return false; 2584 2585 if (con->seq != r.info->seq) { 2586 con->dropped += r.info->seq - con->seq; 2587 con->seq = r.info->seq; 2588 } 2589 2590 /* Skip record that has level above the console loglevel. */ 2591 if (suppress_message_printing(r.info->level)) { 2592 con->seq++; 2593 goto skip; 2594 } 2595 2596 if (con->flags & CON_EXTENDED) { 2597 write_text = &ext_text[0]; 2598 len = info_print_ext_header(ext_text, sizeof(ext_text), r.info); 2599 len += msg_print_ext_body(ext_text + len, sizeof(ext_text) - len, 2600 &r.text_buf[0], r.info->text_len, &r.info->dev_info); 2601 } else { 2602 write_text = &text[0]; 2603 len = record_print_text(&r, console_msg_format & MSG_FORMAT_SYSLOG, printk_time); 2604 } 2605 2606 /* 2607 * While actively printing out messages, if another printk() 2608 * were to occur on another CPU, it may wait for this one to 2609 * finish. This task can not be preempted if there is a 2610 * waiter waiting to take over. 2611 * 2612 * Interrupts are disabled because the hand over to a waiter 2613 * must not be interrupted until the hand over is completed 2614 * (@console_waiter is cleared). 2615 */ 2616 printk_safe_enter_irqsave(flags); 2617 console_lock_spinning_enable(); 2618 2619 stop_critical_timings(); /* don't trace print latency */ 2620 call_console_driver(con, write_text, len); 2621 start_critical_timings(); 2622 2623 con->seq++; 2624 2625 *handover = console_lock_spinning_disable_and_check(); 2626 printk_safe_exit_irqrestore(flags); 2627 2630 skip: 2631 return true; 2632 } 2633 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org