2 * linux/kernel/printk.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
6 * Modified to make sys_syslog() more flexible: added commands to
7 * return the last 4k of kernel messages, regardless of whether
8 * they've been read or not. Added option to suppress kernel printk's
9 * to the console. Added hook for sending the console messages
10 * elsewhere, in preparation for a serial line console (someday).
12 * Modified for sysctl support, 1/8/97, Chris Horn.
13 * Fixed SMP synchronization, 08/08/99, Manfred Spraul
14 * manfred@colorfullife.com
15 * Rewrote bits to get rid of console_lock
16 * 01Mar01 Andrew Morton
19 #include <linux/kernel.h>
21 #include <linux/tty.h>
22 #include <linux/tty_driver.h>
23 #include <linux/console.h>
24 #include <linux/init.h>
25 #include <linux/jiffies.h>
26 #include <linux/nmi.h>
27 #include <linux/module.h>
28 #include <linux/moduleparam.h>
29 #include <linux/interrupt.h> /* For in_interrupt() */
30 #include <linux/delay.h>
31 #include <linux/smp.h>
32 #include <linux/security.h>
33 #include <linux/bootmem.h>
34 #include <linux/memblock.h>
35 #include <linux/aio.h>
36 #include <linux/syscalls.h>
37 #include <linux/kexec.h>
38 #include <linux/kdb.h>
39 #include <linux/ratelimit.h>
40 #include <linux/kmsg_dump.h>
41 #include <linux/syslog.h>
42 #include <linux/cpu.h>
43 #include <linux/notifier.h>
44 #include <linux/rculist.h>
45 #include <linux/poll.h>
46 #include <linux/irq_work.h>
47 #include <linux/utsname.h>
49 #include <asm/uaccess.h>
51 #define CREATE_TRACE_POINTS
52 #include <trace/events/printk.h>
54 /* printk's without a loglevel use this.. */
55 #define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL
57 /* We show everything that is MORE important than this.. */
58 #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */
59 #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */
61 int console_printk[4] = {
62 DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */
63 DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */
64 MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */
65 DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */
69 * Low level drivers may need that to know if they can schedule in
70 * their unblank() callback or not. So let's export it.
73 EXPORT_SYMBOL(oops_in_progress);
76 * console_sem protects the console_drivers list, and also
77 * provides serialisation for access to the entire console
80 static DEFINE_SEMAPHORE(console_sem);
81 struct console *console_drivers;
82 EXPORT_SYMBOL_GPL(console_drivers);
85 static struct lockdep_map console_lock_dep_map = {
86 .name = "console_lock"
91 * This is used for debugging the mess that is the VT code by
92 * keeping track if we have the console semaphore held. It's
93 * definitely not the perfect debug tool (we don't know if _WE_
94 * hold it are racing, but it helps tracking those weird code
95 * path in the console code where we end up in places I want
96 * locked without the console sempahore held
98 static int console_locked, console_suspended;
101 * If exclusive_console is non-NULL then only this console is to be printed to.
103 static struct console *exclusive_console;
106 * Array of consoles built from command line options (console=)
108 struct console_cmdline
110 char name[8]; /* Name of the driver */
111 int index; /* Minor dev. to use */
112 char *options; /* Options for the driver */
113 #ifdef CONFIG_A11Y_BRAILLE_CONSOLE
114 char *brl_options; /* Options for braille driver */
118 #define MAX_CMDLINECONSOLES 8
120 static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES];
121 static int selected_console = -1;
122 static int preferred_console = -1;
123 int console_set_on_cmdline;
124 EXPORT_SYMBOL(console_set_on_cmdline);
126 /* Flag: console code may call schedule() */
127 static int console_may_schedule;
130 * The printk log buffer consists of a chain of concatenated variable
131 * length records. Every record starts with a record header, containing
132 * the overall length of the record.
134 * The heads to the first and last entry in the buffer, as well as the
135 * sequence numbers of these both entries are maintained when messages
138 * If the heads indicate available messages, the length in the header
139 * tells the start next message. A length == 0 for the next message
140 * indicates a wrap-around to the beginning of the buffer.
142 * Every record carries the monotonic timestamp in microseconds, as well as
143 * the standard userspace syslog level and syslog facility. The usual
144 * kernel messages use LOG_KERN; userspace-injected messages always carry
145 * a matching syslog facility, by default LOG_USER. The origin of every
146 * message can be reliably determined that way.
148 * The human readable log message directly follows the message header. The
149 * length of the message text is stored in the header, the stored message
152 * Optionally, a message can carry a dictionary of properties (key/value pairs),
153 * to provide userspace with a machine-readable message context.
155 * Examples for well-defined, commonly used property names are:
156 * DEVICE=b12:8 device identifier
160 * +sound:card0 subsystem:devname
161 * SUBSYSTEM=pci driver-core subsystem name
163 * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value
164 * follows directly after a '=' character. Every property is terminated by
165 * a '\0' character. The last property is not terminated.
167 * Example of a message structure:
168 * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec
169 * 0008 34 00 record is 52 bytes long
170 * 000a 0b 00 text is 11 bytes long
171 * 000c 1f 00 dictionary is 23 bytes long
172 * 000e 03 00 LOG_KERN (facility) LOG_ERR (level)
173 * 0010 69 74 27 73 20 61 20 6c "it's a l"
175 * 001b 44 45 56 49 43 "DEVIC"
176 * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D"
177 * 52 49 56 45 52 3d 62 75 "RIVER=bu"
179 * 0032 00 00 00 padding to next message header
181 * The 'struct log' buffer header must never be directly exported to
182 * userspace, it is a kernel-private implementation detail that might
183 * need to be changed in the future, when the requirements change.
185 * /dev/kmsg exports the structured data in the following line format:
186 * "level,sequnum,timestamp;<message text>\n"
188 * The optional key/value pairs are attached as continuation lines starting
189 * with a space character and terminated by a newline. All possible
190 * non-prinatable characters are escaped in the "\xff" notation.
192 * Users of the export format should ignore possible additional values
193 * separated by ',', and find the message after the ';' character.
197 LOG_NOCONS = 1, /* already flushed, do not print to console */
198 LOG_NEWLINE = 2, /* text ended with a newline */
199 LOG_PREFIX = 4, /* text started with a prefix */
200 LOG_CONT = 8, /* text is a fragment of a continuation line */
204 u64 ts_nsec; /* timestamp in nanoseconds */
205 u16 len; /* length of entire record */
206 u16 text_len; /* length of text buffer */
207 u16 dict_len; /* length of dictionary buffer */
208 u8 facility; /* syslog facility */
209 u8 flags:5; /* internal record flags */
210 u8 level:3; /* syslog level */
214 * The logbuf_lock protects kmsg buffer, indices, counters. It is also
215 * used in interesting ways to provide interlocking in console_unlock();
217 static DEFINE_RAW_SPINLOCK(logbuf_lock);
220 DECLARE_WAIT_QUEUE_HEAD(log_wait);
221 /* the next printk record to read by syslog(READ) or /proc/kmsg */
222 static u64 syslog_seq;
223 static u32 syslog_idx;
224 static enum log_flags syslog_prev;
225 static size_t syslog_partial;
227 /* index and sequence number of the first record stored in the buffer */
228 static u64 log_first_seq;
229 static u32 log_first_idx;
231 /* index and sequence number of the next record to store in the buffer */
232 static u64 log_next_seq;
233 static u32 log_next_idx;
235 /* the next printk record to write to the console */
236 static u64 console_seq;
237 static u32 console_idx;
238 static enum log_flags console_prev;
240 /* the next printk record to read after the last 'clear' command */
241 static u64 clear_seq;
242 static u32 clear_idx;
244 #define PREFIX_MAX 32
245 #define LOG_LINE_MAX 1024 - PREFIX_MAX
248 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
251 #define LOG_ALIGN __alignof__(struct log)
253 #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
254 static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
255 static char *log_buf = __log_buf;
256 static u32 log_buf_len = __LOG_BUF_LEN;
258 /* cpu currently holding logbuf_lock */
259 static volatile unsigned int logbuf_cpu = UINT_MAX;
261 /* human readable text of the record */
262 static char *log_text(const struct log *msg)
264 return (char *)msg + sizeof(struct log);
267 /* optional key/value pair dictionary attached to the record */
268 static char *log_dict(const struct log *msg)
270 return (char *)msg + sizeof(struct log) + msg->text_len;
273 /* get record by index; idx must point to valid msg */
274 static struct log *log_from_idx(u32 idx)
276 struct log *msg = (struct log *)(log_buf + idx);
279 * A length == 0 record is the end of buffer marker. Wrap around and
280 * read the message at the start of the buffer.
283 return (struct log *)log_buf;
287 /* get next record; idx must point to valid msg */
288 static u32 log_next(u32 idx)
290 struct log *msg = (struct log *)(log_buf + idx);
292 /* length == 0 indicates the end of the buffer; wrap */
294 * A length == 0 record is the end of buffer marker. Wrap around and
295 * read the message at the start of the buffer as *this* one, and
296 * return the one after that.
299 msg = (struct log *)log_buf;
302 return idx + msg->len;
305 /* insert record into the buffer, discard old ones, update heads */
306 static void log_store(int facility, int level,
307 enum log_flags flags, u64 ts_nsec,
308 const char *dict, u16 dict_len,
309 const char *text, u16 text_len)
314 /* number of '\0' padding bytes to next message */
315 size = sizeof(struct log) + text_len + dict_len;
316 pad_len = (-size) & (LOG_ALIGN - 1);
319 while (log_first_seq < log_next_seq) {
322 if (log_next_idx > log_first_idx)
323 free = max(log_buf_len - log_next_idx, log_first_idx);
325 free = log_first_idx - log_next_idx;
327 if (free > size + sizeof(struct log))
330 /* drop old messages until we have enough contiuous space */
331 log_first_idx = log_next(log_first_idx);
335 if (log_next_idx + size + sizeof(struct log) >= log_buf_len) {
337 * This message + an additional empty header does not fit
338 * at the end of the buffer. Add an empty header with len == 0
339 * to signify a wrap around.
341 memset(log_buf + log_next_idx, 0, sizeof(struct log));
346 msg = (struct log *)(log_buf + log_next_idx);
347 memcpy(log_text(msg), text, text_len);
348 msg->text_len = text_len;
349 memcpy(log_dict(msg), dict, dict_len);
350 msg->dict_len = dict_len;
351 msg->facility = facility;
352 msg->level = level & 7;
353 msg->flags = flags & 0x1f;
355 msg->ts_nsec = ts_nsec;
357 msg->ts_nsec = local_clock();
358 memset(log_dict(msg) + dict_len, 0, pad_len);
359 msg->len = sizeof(struct log) + text_len + dict_len + pad_len;
362 log_next_idx += msg->len;
366 /* /dev/kmsg - userspace message inject/listen interface */
367 struct devkmsg_user {
375 static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv,
376 unsigned long count, loff_t pos)
380 int level = default_message_loglevel;
381 int facility = 1; /* LOG_USER */
382 size_t len = iov_length(iv, count);
385 if (len > LOG_LINE_MAX)
387 buf = kmalloc(len+1, GFP_KERNEL);
392 for (i = 0; i < count; i++) {
393 if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) {
397 line += iv[i].iov_len;
401 * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace
402 * the decimal value represents 32bit, the lower 3 bit are the log
403 * level, the rest are the log facility.
405 * If no prefix or no userspace facility is specified, we
406 * enforce LOG_USER, to be able to reliably distinguish
407 * kernel-generated messages from userspace-injected ones.
410 if (line[0] == '<') {
413 i = simple_strtoul(line+1, &endp, 10);
414 if (endp && endp[0] == '>') {
425 printk_emit(facility, level, NULL, 0, "%s", line);
431 static ssize_t devkmsg_read(struct file *file, char __user *buf,
432 size_t count, loff_t *ppos)
434 struct devkmsg_user *user = file->private_data;
445 ret = mutex_lock_interruptible(&user->lock);
448 raw_spin_lock_irq(&logbuf_lock);
449 while (user->seq == log_next_seq) {
450 if (file->f_flags & O_NONBLOCK) {
452 raw_spin_unlock_irq(&logbuf_lock);
456 raw_spin_unlock_irq(&logbuf_lock);
457 ret = wait_event_interruptible(log_wait,
458 user->seq != log_next_seq);
461 raw_spin_lock_irq(&logbuf_lock);
464 if (user->seq < log_first_seq) {
465 /* our last seen message is gone, return error and reset */
466 user->idx = log_first_idx;
467 user->seq = log_first_seq;
469 raw_spin_unlock_irq(&logbuf_lock);
473 msg = log_from_idx(user->idx);
474 ts_usec = msg->ts_nsec;
475 do_div(ts_usec, 1000);
478 * If we couldn't merge continuation line fragments during the print,
479 * export the stored flags to allow an optional external merge of the
480 * records. Merging the records isn't always neccessarily correct, like
481 * when we hit a race during printing. In most cases though, it produces
482 * better readable output. 'c' in the record flags mark the first
483 * fragment of a line, '+' the following.
485 if (msg->flags & LOG_CONT && !(user->prev & LOG_CONT))
487 else if ((msg->flags & LOG_CONT) ||
488 ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)))
491 len = sprintf(user->buf, "%u,%llu,%llu,%c;",
492 (msg->facility << 3) | msg->level,
493 user->seq, ts_usec, cont);
494 user->prev = msg->flags;
496 /* escape non-printable characters */
497 for (i = 0; i < msg->text_len; i++) {
498 unsigned char c = log_text(msg)[i];
500 if (c < ' ' || c >= 127 || c == '\\')
501 len += sprintf(user->buf + len, "\\x%02x", c);
503 user->buf[len++] = c;
505 user->buf[len++] = '\n';
510 for (i = 0; i < msg->dict_len; i++) {
511 unsigned char c = log_dict(msg)[i];
514 user->buf[len++] = ' ';
519 user->buf[len++] = '\n';
524 if (c < ' ' || c >= 127 || c == '\\') {
525 len += sprintf(user->buf + len, "\\x%02x", c);
529 user->buf[len++] = c;
531 user->buf[len++] = '\n';
534 user->idx = log_next(user->idx);
536 raw_spin_unlock_irq(&logbuf_lock);
543 if (copy_to_user(buf, user->buf, len)) {
549 mutex_unlock(&user->lock);
553 static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
555 struct devkmsg_user *user = file->private_data;
563 raw_spin_lock_irq(&logbuf_lock);
566 /* the first record */
567 user->idx = log_first_idx;
568 user->seq = log_first_seq;
572 * The first record after the last SYSLOG_ACTION_CLEAR,
573 * like issued by 'dmesg -c'. Reading /dev/kmsg itself
574 * changes no global state, and does not clear anything.
576 user->idx = clear_idx;
577 user->seq = clear_seq;
580 /* after the last record */
581 user->idx = log_next_idx;
582 user->seq = log_next_seq;
587 raw_spin_unlock_irq(&logbuf_lock);
591 static unsigned int devkmsg_poll(struct file *file, poll_table *wait)
593 struct devkmsg_user *user = file->private_data;
597 return POLLERR|POLLNVAL;
599 poll_wait(file, &log_wait, wait);
601 raw_spin_lock_irq(&logbuf_lock);
602 if (user->seq < log_next_seq) {
603 /* return error when data has vanished underneath us */
604 if (user->seq < log_first_seq)
605 ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI;
607 ret = POLLIN|POLLRDNORM;
609 raw_spin_unlock_irq(&logbuf_lock);
614 static int devkmsg_open(struct inode *inode, struct file *file)
616 struct devkmsg_user *user;
619 /* write-only does not need any file context */
620 if ((file->f_flags & O_ACCMODE) == O_WRONLY)
623 err = security_syslog(SYSLOG_ACTION_READ_ALL);
627 user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL);
631 mutex_init(&user->lock);
633 raw_spin_lock_irq(&logbuf_lock);
634 user->idx = log_first_idx;
635 user->seq = log_first_seq;
636 raw_spin_unlock_irq(&logbuf_lock);
638 file->private_data = user;
642 static int devkmsg_release(struct inode *inode, struct file *file)
644 struct devkmsg_user *user = file->private_data;
649 mutex_destroy(&user->lock);
654 const struct file_operations kmsg_fops = {
655 .open = devkmsg_open,
656 .read = devkmsg_read,
657 .aio_write = devkmsg_writev,
658 .llseek = devkmsg_llseek,
659 .poll = devkmsg_poll,
660 .release = devkmsg_release,
665 * This appends the listed symbols to /proc/vmcoreinfo
667 * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to
668 * obtain access to symbols that are otherwise very difficult to locate. These
669 * symbols are specifically used so that utilities can access and extract the
670 * dmesg log from a vmcore file after a crash.
672 void log_buf_kexec_setup(void)
674 VMCOREINFO_SYMBOL(log_buf);
675 VMCOREINFO_SYMBOL(log_buf_len);
676 VMCOREINFO_SYMBOL(log_first_idx);
677 VMCOREINFO_SYMBOL(log_next_idx);
679 * Export struct log size and field offsets. User space tools can
680 * parse it and detect any changes to structure down the line.
682 VMCOREINFO_STRUCT_SIZE(log);
683 VMCOREINFO_OFFSET(log, ts_nsec);
684 VMCOREINFO_OFFSET(log, len);
685 VMCOREINFO_OFFSET(log, text_len);
686 VMCOREINFO_OFFSET(log, dict_len);
690 /* requested log_buf_len from kernel cmdline */
691 static unsigned long __initdata new_log_buf_len;
693 /* save requested log_buf_len since it's too early to process it */
694 static int __init log_buf_len_setup(char *str)
696 unsigned size = memparse(str, &str);
699 size = roundup_pow_of_two(size);
700 if (size > log_buf_len)
701 new_log_buf_len = size;
705 early_param("log_buf_len", log_buf_len_setup);
707 void __init setup_log_buf(int early)
713 if (!new_log_buf_len)
719 mem = memblock_alloc(new_log_buf_len, PAGE_SIZE);
722 new_log_buf = __va(mem);
724 new_log_buf = alloc_bootmem_nopanic(new_log_buf_len);
727 if (unlikely(!new_log_buf)) {
728 pr_err("log_buf_len: %ld bytes not available\n",
733 raw_spin_lock_irqsave(&logbuf_lock, flags);
734 log_buf_len = new_log_buf_len;
735 log_buf = new_log_buf;
737 free = __LOG_BUF_LEN - log_next_idx;
738 memcpy(log_buf, __log_buf, __LOG_BUF_LEN);
739 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
741 pr_info("log_buf_len: %d\n", log_buf_len);
742 pr_info("early log buf free: %d(%d%%)\n",
743 free, (free * 100) / __LOG_BUF_LEN);
746 static bool __read_mostly ignore_loglevel;
748 static int __init ignore_loglevel_setup(char *str)
751 printk(KERN_INFO "debug: ignoring loglevel setting.\n");
756 early_param("ignore_loglevel", ignore_loglevel_setup);
757 module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR);
758 MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
759 "print all kernel messages to the console.");
761 #ifdef CONFIG_BOOT_PRINTK_DELAY
763 static int boot_delay; /* msecs delay after each printk during bootup */
764 static unsigned long long loops_per_msec; /* based on boot_delay */
766 static int __init boot_delay_setup(char *str)
770 lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */
771 loops_per_msec = (unsigned long long)lpj / 1000 * HZ;
773 get_option(&str, &boot_delay);
774 if (boot_delay > 10 * 1000)
777 pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, "
778 "HZ: %d, loops_per_msec: %llu\n",
779 boot_delay, preset_lpj, lpj, HZ, loops_per_msec);
782 __setup("boot_delay=", boot_delay_setup);
784 static void boot_delay_msec(int level)
786 unsigned long long k;
787 unsigned long timeout;
789 if ((boot_delay == 0 || system_state != SYSTEM_BOOTING)
790 || (level >= console_loglevel && !ignore_loglevel)) {
794 k = (unsigned long long)loops_per_msec * boot_delay;
796 timeout = jiffies + msecs_to_jiffies(boot_delay);
801 * use (volatile) jiffies to prevent
802 * compiler reduction; loop termination via jiffies
803 * is secondary and may or may not happen.
805 if (time_after(jiffies, timeout))
807 touch_nmi_watchdog();
811 static inline void boot_delay_msec(int level)
816 #ifdef CONFIG_SECURITY_DMESG_RESTRICT
817 int dmesg_restrict = 1;
822 static int syslog_action_restricted(int type)
826 /* Unless restricted, we allow "read all" and "get buffer size" for everybody */
827 return type != SYSLOG_ACTION_READ_ALL && type != SYSLOG_ACTION_SIZE_BUFFER;
830 static int check_syslog_permissions(int type, bool from_file)
833 * If this is from /proc/kmsg and we've already opened it, then we've
834 * already done the capabilities checks at open time.
836 if (from_file && type != SYSLOG_ACTION_OPEN)
839 if (syslog_action_restricted(type)) {
840 if (capable(CAP_SYSLOG))
842 /* For historical reasons, accept CAP_SYS_ADMIN too, with a warning */
843 if (capable(CAP_SYS_ADMIN)) {
844 printk_once(KERN_WARNING "%s (%d): "
845 "Attempt to access syslog with CAP_SYS_ADMIN "
846 "but no CAP_SYSLOG (deprecated).\n",
847 current->comm, task_pid_nr(current));
855 #if defined(CONFIG_PRINTK_TIME)
856 static bool printk_time = 1;
858 static bool printk_time;
860 module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
862 static size_t print_time(u64 ts, char *buf)
864 unsigned long rem_nsec;
869 rem_nsec = do_div(ts, 1000000000);
872 return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts);
874 return sprintf(buf, "[%5lu.%06lu] ",
875 (unsigned long)ts, rem_nsec / 1000);
878 static size_t print_prefix(const struct log *msg, bool syslog, char *buf)
881 unsigned int prefix = (msg->facility << 3) | msg->level;
885 len += sprintf(buf, "<%u>", prefix);
890 else if (prefix > 99)
897 len += print_time(msg->ts_nsec, buf ? buf + len : NULL);
901 static size_t msg_print_text(const struct log *msg, enum log_flags prev,
902 bool syslog, char *buf, size_t size)
904 const char *text = log_text(msg);
905 size_t text_size = msg->text_len;
910 if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))
913 if (msg->flags & LOG_CONT) {
914 if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE))
917 if (!(msg->flags & LOG_NEWLINE))
922 const char *next = memchr(text, '\n', text_size);
926 text_len = next - text;
928 text_size -= next - text;
930 text_len = text_size;
934 if (print_prefix(msg, syslog, NULL) +
935 text_len + 1 >= size - len)
939 len += print_prefix(msg, syslog, buf + len);
940 memcpy(buf + len, text, text_len);
945 /* SYSLOG_ACTION_* buffer size only calculation */
947 len += print_prefix(msg, syslog, NULL);
960 static int syslog_print(char __user *buf, int size)
966 text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
974 raw_spin_lock_irq(&logbuf_lock);
975 if (syslog_seq < log_first_seq) {
976 /* messages are gone, move to first one */
977 syslog_seq = log_first_seq;
978 syslog_idx = log_first_idx;
982 if (syslog_seq == log_next_seq) {
983 raw_spin_unlock_irq(&logbuf_lock);
987 skip = syslog_partial;
988 msg = log_from_idx(syslog_idx);
989 n = msg_print_text(msg, syslog_prev, true, text,
990 LOG_LINE_MAX + PREFIX_MAX);
991 if (n - syslog_partial <= size) {
992 /* message fits into buffer, move forward */
993 syslog_idx = log_next(syslog_idx);
995 syslog_prev = msg->flags;
999 /* partial read(), remember position */
1001 syslog_partial += n;
1004 raw_spin_unlock_irq(&logbuf_lock);
1009 if (copy_to_user(buf, text + skip, n)) {
1024 static int syslog_print_all(char __user *buf, int size, bool clear)
1029 text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
1033 raw_spin_lock_irq(&logbuf_lock);
1038 enum log_flags prev;
1040 if (clear_seq < log_first_seq) {
1041 /* messages are gone, move to first available one */
1042 clear_seq = log_first_seq;
1043 clear_idx = log_first_idx;
1047 * Find first record that fits, including all following records,
1048 * into the user-provided buffer for this dump.
1053 while (seq < log_next_seq) {
1054 struct log *msg = log_from_idx(idx);
1056 len += msg_print_text(msg, prev, true, NULL, 0);
1058 idx = log_next(idx);
1062 /* move first record forward until length fits into the buffer */
1066 while (len > size && seq < log_next_seq) {
1067 struct log *msg = log_from_idx(idx);
1069 len -= msg_print_text(msg, prev, true, NULL, 0);
1071 idx = log_next(idx);
1075 /* last message fitting into this dump */
1076 next_seq = log_next_seq;
1080 while (len >= 0 && seq < next_seq) {
1081 struct log *msg = log_from_idx(idx);
1084 textlen = msg_print_text(msg, prev, true, text,
1085 LOG_LINE_MAX + PREFIX_MAX);
1090 idx = log_next(idx);
1094 raw_spin_unlock_irq(&logbuf_lock);
1095 if (copy_to_user(buf + len, text, textlen))
1099 raw_spin_lock_irq(&logbuf_lock);
1101 if (seq < log_first_seq) {
1102 /* messages are gone, move to next one */
1103 seq = log_first_seq;
1104 idx = log_first_idx;
1111 clear_seq = log_next_seq;
1112 clear_idx = log_next_idx;
1114 raw_spin_unlock_irq(&logbuf_lock);
1120 int do_syslog(int type, char __user *buf, int len, bool from_file)
1123 static int saved_console_loglevel = -1;
1126 error = check_syslog_permissions(type, from_file);
1130 error = security_syslog(type);
1135 case SYSLOG_ACTION_CLOSE: /* Close log */
1137 case SYSLOG_ACTION_OPEN: /* Open log */
1139 case SYSLOG_ACTION_READ: /* Read from log */
1141 if (!buf || len < 0)
1146 if (!access_ok(VERIFY_WRITE, buf, len)) {
1150 error = wait_event_interruptible(log_wait,
1151 syslog_seq != log_next_seq);
1154 error = syslog_print(buf, len);
1156 /* Read/clear last kernel messages */
1157 case SYSLOG_ACTION_READ_CLEAR:
1160 /* Read last kernel messages */
1161 case SYSLOG_ACTION_READ_ALL:
1163 if (!buf || len < 0)
1168 if (!access_ok(VERIFY_WRITE, buf, len)) {
1172 error = syslog_print_all(buf, len, clear);
1174 /* Clear ring buffer */
1175 case SYSLOG_ACTION_CLEAR:
1176 syslog_print_all(NULL, 0, true);
1178 /* Disable logging to console */
1179 case SYSLOG_ACTION_CONSOLE_OFF:
1180 if (saved_console_loglevel == -1)
1181 saved_console_loglevel = console_loglevel;
1182 console_loglevel = minimum_console_loglevel;
1184 /* Enable logging to console */
1185 case SYSLOG_ACTION_CONSOLE_ON:
1186 if (saved_console_loglevel != -1) {
1187 console_loglevel = saved_console_loglevel;
1188 saved_console_loglevel = -1;
1191 /* Set level of messages printed to console */
1192 case SYSLOG_ACTION_CONSOLE_LEVEL:
1194 if (len < 1 || len > 8)
1196 if (len < minimum_console_loglevel)
1197 len = minimum_console_loglevel;
1198 console_loglevel = len;
1199 /* Implicitly re-enable logging to console */
1200 saved_console_loglevel = -1;
1203 /* Number of chars in the log buffer */
1204 case SYSLOG_ACTION_SIZE_UNREAD:
1205 raw_spin_lock_irq(&logbuf_lock);
1206 if (syslog_seq < log_first_seq) {
1207 /* messages are gone, move to first one */
1208 syslog_seq = log_first_seq;
1209 syslog_idx = log_first_idx;
1215 * Short-cut for poll(/"proc/kmsg") which simply checks
1216 * for pending data, not the size; return the count of
1217 * records, not the length.
1219 error = log_next_idx - syslog_idx;
1221 u64 seq = syslog_seq;
1222 u32 idx = syslog_idx;
1223 enum log_flags prev = syslog_prev;
1226 while (seq < log_next_seq) {
1227 struct log *msg = log_from_idx(idx);
1229 error += msg_print_text(msg, prev, true, NULL, 0);
1230 idx = log_next(idx);
1234 error -= syslog_partial;
1236 raw_spin_unlock_irq(&logbuf_lock);
1238 /* Size of the log buffer */
1239 case SYSLOG_ACTION_SIZE_BUFFER:
1240 error = log_buf_len;
1250 SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
1252 return do_syslog(type, buf, len, SYSLOG_FROM_CALL);
1256 * Call the console drivers, asking them to write out
1257 * log_buf[start] to log_buf[end - 1].
1258 * The console_lock must be held.
1260 static void call_console_drivers(int level, const char *text, size_t len)
1262 struct console *con;
1264 trace_console(text, len);
1266 if (level >= console_loglevel && !ignore_loglevel)
1268 if (!console_drivers)
1271 for_each_console(con) {
1272 if (exclusive_console && con != exclusive_console)
1274 if (!(con->flags & CON_ENABLED))
1278 if (!cpu_online(smp_processor_id()) &&
1279 !(con->flags & CON_ANYTIME))
1281 con->write(con, text, len);
1286 * Zap console related locks when oopsing. Only zap at most once
1287 * every 10 seconds, to leave time for slow consoles to print a
1290 static void zap_locks(void)
1292 static unsigned long oops_timestamp;
1294 if (time_after_eq(jiffies, oops_timestamp) &&
1295 !time_after(jiffies, oops_timestamp + 30 * HZ))
1298 oops_timestamp = jiffies;
1301 /* If a crash is occurring, make sure we can't deadlock */
1302 raw_spin_lock_init(&logbuf_lock);
1303 /* And make sure that we print immediately */
1304 sema_init(&console_sem, 1);
1307 /* Check if we have any console registered that can be called early in boot. */
1308 static int have_callable_console(void)
1310 struct console *con;
1312 for_each_console(con)
1313 if (con->flags & CON_ANYTIME)
1320 * Can we actually use the console at this time on this cpu?
1322 * Console drivers may assume that per-cpu resources have
1323 * been allocated. So unless they're explicitly marked as
1324 * being able to cope (CON_ANYTIME) don't call them until
1325 * this CPU is officially up.
1327 static inline int can_use_console(unsigned int cpu)
1329 return cpu_online(cpu) || have_callable_console();
1333 * Try to get console ownership to actually show the kernel
1334 * messages from a 'printk'. Return true (and with the
1335 * console_lock held, and 'console_locked' set) if it
1336 * is successful, false otherwise.
1338 * This gets called with the 'logbuf_lock' spinlock held and
1339 * interrupts disabled. It should return with 'lockbuf_lock'
1340 * released but interrupts still disabled.
1342 static int console_trylock_for_printk(unsigned int cpu)
1343 __releases(&logbuf_lock)
1345 int retval = 0, wake = 0;
1347 if (console_trylock()) {
1351 * If we can't use the console, we need to release
1352 * the console semaphore by hand to avoid flushing
1353 * the buffer. We need to hold the console semaphore
1354 * in order to do this test safely.
1356 if (!can_use_console(cpu)) {
1362 logbuf_cpu = UINT_MAX;
1365 raw_spin_unlock(&logbuf_lock);
1369 int printk_delay_msec __read_mostly;
1371 static inline void printk_delay(void)
1373 if (unlikely(printk_delay_msec)) {
1374 int m = printk_delay_msec;
1378 touch_nmi_watchdog();
1384 * Continuation lines are buffered, and not committed to the record buffer
1385 * until the line is complete, or a race forces it. The line fragments
1386 * though, are printed immediately to the consoles to ensure everything has
1387 * reached the console in case of a kernel crash.
1389 static struct cont {
1390 char buf[LOG_LINE_MAX];
1391 size_t len; /* length == 0 means unused buffer */
1392 size_t cons; /* bytes written to console */
1393 struct task_struct *owner; /* task of first print*/
1394 u64 ts_nsec; /* time of first print */
1395 u8 level; /* log level of first message */
1396 u8 facility; /* log level of first message */
1397 enum log_flags flags; /* prefix, newline flags */
1398 bool flushed:1; /* buffer sealed and committed */
1401 static void cont_flush(enum log_flags flags)
1410 * If a fragment of this line was directly flushed to the
1411 * console; wait for the console to pick up the rest of the
1412 * line. LOG_NOCONS suppresses a duplicated output.
1414 log_store(cont.facility, cont.level, flags | LOG_NOCONS,
1415 cont.ts_nsec, NULL, 0, cont.buf, cont.len);
1417 cont.flushed = true;
1420 * If no fragment of this line ever reached the console,
1421 * just submit it to the store and free the buffer.
1423 log_store(cont.facility, cont.level, flags, 0,
1424 NULL, 0, cont.buf, cont.len);
1429 static bool cont_add(int facility, int level, const char *text, size_t len)
1431 if (cont.len && cont.flushed)
1434 if (cont.len + len > sizeof(cont.buf)) {
1435 /* the line gets too long, split it up in separate records */
1436 cont_flush(LOG_CONT);
1441 cont.facility = facility;
1443 cont.owner = current;
1444 cont.ts_nsec = local_clock();
1447 cont.flushed = false;
1450 memcpy(cont.buf + cont.len, text, len);
1453 if (cont.len > (sizeof(cont.buf) * 80) / 100)
1454 cont_flush(LOG_CONT);
1459 static size_t cont_print_text(char *text, size_t size)
1464 if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) {
1465 textlen += print_time(cont.ts_nsec, text);
1469 len = cont.len - cont.cons;
1473 memcpy(text + textlen, cont.buf + cont.cons, len);
1475 cont.cons = cont.len;
1479 if (cont.flags & LOG_NEWLINE)
1480 text[textlen++] = '\n';
1481 /* got everything, release buffer */
1487 asmlinkage int vprintk_emit(int facility, int level,
1488 const char *dict, size_t dictlen,
1489 const char *fmt, va_list args)
1491 static int recursion_bug;
1492 static char textbuf[LOG_LINE_MAX];
1493 char *text = textbuf;
1495 enum log_flags lflags = 0;
1496 unsigned long flags;
1498 int printed_len = 0;
1500 boot_delay_msec(level);
1503 /* This stops the holder of console_sem just where we want him */
1504 local_irq_save(flags);
1505 this_cpu = smp_processor_id();
1508 * Ouch, printk recursed into itself!
1510 if (unlikely(logbuf_cpu == this_cpu)) {
1512 * If a crash is occurring during printk() on this CPU,
1513 * then try to get the crash message out but make sure
1514 * we can't deadlock. Otherwise just return to avoid the
1515 * recursion and return - but flag the recursion so that
1516 * it can be printed at the next appropriate moment:
1518 if (!oops_in_progress && !lockdep_recursing(current)) {
1520 goto out_restore_irqs;
1526 raw_spin_lock(&logbuf_lock);
1527 logbuf_cpu = this_cpu;
1529 if (recursion_bug) {
1530 static const char recursion_msg[] =
1531 "BUG: recent printk recursion!";
1534 printed_len += strlen(recursion_msg);
1535 /* emit KERN_CRIT message */
1536 log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0,
1537 NULL, 0, recursion_msg, printed_len);
1541 * The printf needs to come first; we need the syslog
1542 * prefix which might be passed-in as a parameter.
1544 text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
1546 /* mark and strip a trailing newline */
1547 if (text_len && text[text_len-1] == '\n') {
1549 lflags |= LOG_NEWLINE;
1552 /* strip kernel syslog prefix and extract log level or control flags */
1553 if (facility == 0) {
1554 int kern_level = printk_get_level(text);
1557 const char *end_of_header = printk_skip_level(text);
1558 switch (kern_level) {
1561 level = kern_level - '0';
1562 case 'd': /* KERN_DEFAULT */
1563 lflags |= LOG_PREFIX;
1564 case 'c': /* KERN_CONT */
1567 text_len -= end_of_header - text;
1568 text = (char *)end_of_header;
1573 level = default_message_loglevel;
1576 lflags |= LOG_PREFIX|LOG_NEWLINE;
1578 if (!(lflags & LOG_NEWLINE)) {
1580 * Flush the conflicting buffer. An earlier newline was missing,
1581 * or another task also prints continuation lines.
1583 if (cont.len && (lflags & LOG_PREFIX || cont.owner != current))
1584 cont_flush(LOG_NEWLINE);
1586 /* buffer line if possible, otherwise store it right away */
1587 if (!cont_add(facility, level, text, text_len))
1588 log_store(facility, level, lflags | LOG_CONT, 0,
1589 dict, dictlen, text, text_len);
1591 bool stored = false;
1594 * If an earlier newline was missing and it was the same task,
1595 * either merge it with the current buffer and flush, or if
1596 * there was a race with interrupts (prefix == true) then just
1597 * flush it out and store this line separately.
1599 if (cont.len && cont.owner == current) {
1600 if (!(lflags & LOG_PREFIX))
1601 stored = cont_add(facility, level, text, text_len);
1602 cont_flush(LOG_NEWLINE);
1606 log_store(facility, level, lflags, 0,
1607 dict, dictlen, text, text_len);
1609 printed_len += text_len;
1612 * Try to acquire and then immediately release the console semaphore.
1613 * The release will print out buffers and wake up /dev/kmsg and syslog()
1616 * The console_trylock_for_printk() function will release 'logbuf_lock'
1617 * regardless of whether it actually gets the console semaphore or not.
1619 if (console_trylock_for_printk(this_cpu))
1624 local_irq_restore(flags);
1628 EXPORT_SYMBOL(vprintk_emit);
1630 asmlinkage int vprintk(const char *fmt, va_list args)
1632 return vprintk_emit(0, -1, NULL, 0, fmt, args);
1634 EXPORT_SYMBOL(vprintk);
1636 asmlinkage int printk_emit(int facility, int level,
1637 const char *dict, size_t dictlen,
1638 const char *fmt, ...)
1643 va_start(args, fmt);
1644 r = vprintk_emit(facility, level, dict, dictlen, fmt, args);
1649 EXPORT_SYMBOL(printk_emit);
1652 * printk - print a kernel message
1653 * @fmt: format string
1655 * This is printk(). It can be called from any context. We want it to work.
1657 * We try to grab the console_lock. If we succeed, it's easy - we log the
1658 * output and call the console drivers. If we fail to get the semaphore, we
1659 * place the output into the log buffer and return. The current holder of
1660 * the console_sem will notice the new output in console_unlock(); and will
1661 * send it to the consoles before releasing the lock.
1663 * One effect of this deferred printing is that code which calls printk() and
1664 * then changes console_loglevel may break. This is because console_loglevel
1665 * is inspected when the actual printing occurs.
1670 * See the vsnprintf() documentation for format string extensions over C99.
1672 asmlinkage int printk(const char *fmt, ...)
1677 #ifdef CONFIG_KGDB_KDB
1678 if (unlikely(kdb_trap_printk)) {
1679 va_start(args, fmt);
1680 r = vkdb_printf(fmt, args);
1685 va_start(args, fmt);
1686 r = vprintk_emit(0, -1, NULL, 0, fmt, args);
1691 EXPORT_SYMBOL(printk);
1693 #else /* CONFIG_PRINTK */
1695 #define LOG_LINE_MAX 0
1696 #define PREFIX_MAX 0
1697 #define LOG_LINE_MAX 0
1698 static u64 syslog_seq;
1699 static u32 syslog_idx;
1700 static u64 console_seq;
1701 static u32 console_idx;
1702 static enum log_flags syslog_prev;
1703 static u64 log_first_seq;
1704 static u32 log_first_idx;
1705 static u64 log_next_seq;
1706 static enum log_flags console_prev;
1707 static struct cont {
1713 static struct log *log_from_idx(u32 idx) { return NULL; }
1714 static u32 log_next(u32 idx) { return 0; }
1715 static void call_console_drivers(int level, const char *text, size_t len) {}
1716 static size_t msg_print_text(const struct log *msg, enum log_flags prev,
1717 bool syslog, char *buf, size_t size) { return 0; }
1718 static size_t cont_print_text(char *text, size_t size) { return 0; }
1720 #endif /* CONFIG_PRINTK */
1722 #ifdef CONFIG_EARLY_PRINTK
1723 struct console *early_console;
1725 void early_vprintk(const char *fmt, va_list ap)
1727 if (early_console) {
1729 int n = vscnprintf(buf, sizeof(buf), fmt, ap);
1731 early_console->write(early_console, buf, n);
1735 asmlinkage void early_printk(const char *fmt, ...)
1740 early_vprintk(fmt, ap);
1745 static int __add_preferred_console(char *name, int idx, char *options,
1748 struct console_cmdline *c;
1752 * See if this tty is not yet registered, and
1753 * if we have a slot free.
1755 for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
1756 if (strcmp(console_cmdline[i].name, name) == 0 &&
1757 console_cmdline[i].index == idx) {
1759 selected_console = i;
1762 if (i == MAX_CMDLINECONSOLES)
1765 selected_console = i;
1766 c = &console_cmdline[i];
1767 strlcpy(c->name, name, sizeof(c->name));
1768 c->options = options;
1769 #ifdef CONFIG_A11Y_BRAILLE_CONSOLE
1770 c->brl_options = brl_options;
1776 * Set up a list of consoles. Called from init/main.c
1778 static int __init console_setup(char *str)
1780 char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */
1781 char *s, *options, *brl_options = NULL;
1784 #ifdef CONFIG_A11Y_BRAILLE_CONSOLE
1785 if (!memcmp(str, "brl,", 4)) {
1788 } else if (!memcmp(str, "brl=", 4)) {
1789 brl_options = str + 4;
1790 str = strchr(brl_options, ',');
1792 printk(KERN_ERR "need port name after brl=\n");
1800 * Decode str into name, index, options.
1802 if (str[0] >= '0' && str[0] <= '9') {
1803 strcpy(buf, "ttyS");
1804 strncpy(buf + 4, str, sizeof(buf) - 5);
1806 strncpy(buf, str, sizeof(buf) - 1);
1808 buf[sizeof(buf) - 1] = 0;
1809 if ((options = strchr(str, ',')) != NULL)
1812 if (!strcmp(str, "ttya"))
1813 strcpy(buf, "ttyS0");
1814 if (!strcmp(str, "ttyb"))
1815 strcpy(buf, "ttyS1");
1817 for (s = buf; *s; s++)
1818 if ((*s >= '0' && *s <= '9') || *s == ',')
1820 idx = simple_strtoul(s, NULL, 10);
1823 __add_preferred_console(buf, idx, options, brl_options);
1824 console_set_on_cmdline = 1;
1827 __setup("console=", console_setup);
1830 * add_preferred_console - add a device to the list of preferred consoles.
1831 * @name: device name
1832 * @idx: device index
1833 * @options: options for this console
1835 * The last preferred console added will be used for kernel messages
1836 * and stdin/out/err for init. Normally this is used by console_setup
1837 * above to handle user-supplied console arguments; however it can also
1838 * be used by arch-specific code either to override the user or more
1839 * commonly to provide a default console (ie from PROM variables) when
1840 * the user has not supplied one.
1842 int add_preferred_console(char *name, int idx, char *options)
1844 return __add_preferred_console(name, idx, options, NULL);
1847 int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options)
1849 struct console_cmdline *c;
1852 for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
1853 if (strcmp(console_cmdline[i].name, name) == 0 &&
1854 console_cmdline[i].index == idx) {
1855 c = &console_cmdline[i];
1856 strlcpy(c->name, name_new, sizeof(c->name));
1857 c->name[sizeof(c->name) - 1] = 0;
1858 c->options = options;
1866 bool console_suspend_enabled = 1;
1867 EXPORT_SYMBOL(console_suspend_enabled);
1869 static int __init console_suspend_disable(char *str)
1871 console_suspend_enabled = 0;
1874 __setup("no_console_suspend", console_suspend_disable);
1875 module_param_named(console_suspend, console_suspend_enabled,
1876 bool, S_IRUGO | S_IWUSR);
1877 MODULE_PARM_DESC(console_suspend, "suspend console during suspend"
1878 " and hibernate operations");
1881 * suspend_console - suspend the console subsystem
1883 * This disables printk() while we go into suspend states
1885 void suspend_console(void)
1887 if (!console_suspend_enabled)
1889 printk("Suspending console(s) (use no_console_suspend to debug)\n");
1891 console_suspended = 1;
1895 void resume_console(void)
1897 if (!console_suspend_enabled)
1900 console_suspended = 0;
1905 * console_cpu_notify - print deferred console messages after CPU hotplug
1906 * @self: notifier struct
1907 * @action: CPU hotplug event
1910 * If printk() is called from a CPU that is not online yet, the messages
1911 * will be spooled but will not show up on the console. This function is
1912 * called when a new CPU comes online (or fails to come up), and ensures
1913 * that any such output gets printed.
1915 static int __cpuinit console_cpu_notify(struct notifier_block *self,
1916 unsigned long action, void *hcpu)
1921 case CPU_DOWN_FAILED:
1922 case CPU_UP_CANCELED:
1930 * console_lock - lock the console system for exclusive use.
1932 * Acquires a lock which guarantees that the caller has
1933 * exclusive access to the console system and the console_drivers list.
1935 * Can sleep, returns nothing.
1937 void console_lock(void)
1942 if (console_suspended)
1945 console_may_schedule = 1;
1946 mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);
1948 EXPORT_SYMBOL(console_lock);
1951 * console_trylock - try to lock the console system for exclusive use.
1953 * Tried to acquire a lock which guarantees that the caller has
1954 * exclusive access to the console system and the console_drivers list.
1956 * returns 1 on success, and 0 on failure to acquire the lock.
1958 int console_trylock(void)
1960 if (down_trylock(&console_sem))
1962 if (console_suspended) {
1967 console_may_schedule = 0;
1968 mutex_acquire(&console_lock_dep_map, 0, 1, _RET_IP_);
1971 EXPORT_SYMBOL(console_trylock);
1973 int is_console_locked(void)
1975 return console_locked;
1978 static void console_cont_flush(char *text, size_t size)
1980 unsigned long flags;
1983 raw_spin_lock_irqsave(&logbuf_lock, flags);
1989 * We still queue earlier records, likely because the console was
1990 * busy. The earlier ones need to be printed before this one, we
1991 * did not flush any fragment so far, so just let it queue up.
1993 if (console_seq < log_next_seq && !cont.cons)
1996 len = cont_print_text(text, size);
1997 raw_spin_unlock(&logbuf_lock);
1998 stop_critical_timings();
1999 call_console_drivers(cont.level, text, len);
2000 start_critical_timings();
2001 local_irq_restore(flags);
2004 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2008 * console_unlock - unlock the console system
2010 * Releases the console_lock which the caller holds on the console system
2011 * and the console driver list.
2013 * While the console_lock was held, console output may have been buffered
2014 * by printk(). If this is the case, console_unlock(); emits
2015 * the output prior to releasing the lock.
2017 * If there is output waiting, we wake /dev/kmsg and syslog() users.
2019 * console_unlock(); may be called from any context.
2021 void console_unlock(void)
2023 static char text[LOG_LINE_MAX + PREFIX_MAX];
2024 static u64 seen_seq;
2025 unsigned long flags;
2026 bool wake_klogd = false;
2029 if (console_suspended) {
2034 console_may_schedule = 0;
2036 /* flush buffered message fragment immediately to console */
2037 console_cont_flush(text, sizeof(text));
2044 raw_spin_lock_irqsave(&logbuf_lock, flags);
2045 if (seen_seq != log_next_seq) {
2047 seen_seq = log_next_seq;
2050 if (console_seq < log_first_seq) {
2051 /* messages are gone, move to first one */
2052 console_seq = log_first_seq;
2053 console_idx = log_first_idx;
2057 if (console_seq == log_next_seq)
2060 msg = log_from_idx(console_idx);
2061 if (msg->flags & LOG_NOCONS) {
2063 * Skip record we have buffered and already printed
2064 * directly to the console when we received it.
2066 console_idx = log_next(console_idx);
2069 * We will get here again when we register a new
2070 * CON_PRINTBUFFER console. Clear the flag so we
2071 * will properly dump everything later.
2073 msg->flags &= ~LOG_NOCONS;
2074 console_prev = msg->flags;
2079 len = msg_print_text(msg, console_prev, false,
2080 text, sizeof(text));
2081 console_idx = log_next(console_idx);
2083 console_prev = msg->flags;
2084 raw_spin_unlock(&logbuf_lock);
2086 stop_critical_timings(); /* don't trace print latency */
2087 call_console_drivers(level, text, len);
2088 start_critical_timings();
2089 local_irq_restore(flags);
2092 mutex_release(&console_lock_dep_map, 1, _RET_IP_);
2094 /* Release the exclusive_console once it is used */
2095 if (unlikely(exclusive_console))
2096 exclusive_console = NULL;
2098 raw_spin_unlock(&logbuf_lock);
2103 * Someone could have filled up the buffer again, so re-check if there's
2104 * something to flush. In case we cannot trylock the console_sem again,
2105 * there's a new owner and the console_unlock() from them will do the
2106 * flush, no worries.
2108 raw_spin_lock(&logbuf_lock);
2109 retry = console_seq != log_next_seq;
2110 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2112 if (retry && console_trylock())
2118 EXPORT_SYMBOL(console_unlock);
2121 * console_conditional_schedule - yield the CPU if required
2123 * If the console code is currently allowed to sleep, and
2124 * if this CPU should yield the CPU to another task, do
2127 * Must be called within console_lock();.
2129 void __sched console_conditional_schedule(void)
2131 if (console_may_schedule)
2134 EXPORT_SYMBOL(console_conditional_schedule);
2136 void console_unblank(void)
2141 * console_unblank can no longer be called in interrupt context unless
2142 * oops_in_progress is set to 1..
2144 if (oops_in_progress) {
2145 if (down_trylock(&console_sem) != 0)
2151 console_may_schedule = 0;
2153 if ((c->flags & CON_ENABLED) && c->unblank)
2159 * Return the console tty driver structure and its associated index
2161 struct tty_driver *console_device(int *index)
2164 struct tty_driver *driver = NULL;
2167 for_each_console(c) {
2170 driver = c->device(c, index);
2179 * Prevent further output on the passed console device so that (for example)
2180 * serial drivers can disable console output before suspending a port, and can
2181 * re-enable output afterwards.
2183 void console_stop(struct console *console)
2186 console->flags &= ~CON_ENABLED;
2189 EXPORT_SYMBOL(console_stop);
2191 void console_start(struct console *console)
2194 console->flags |= CON_ENABLED;
2197 EXPORT_SYMBOL(console_start);
2199 static int __read_mostly keep_bootcon;
2201 static int __init keep_bootcon_setup(char *str)
2204 printk(KERN_INFO "debug: skip boot console de-registration.\n");
2209 early_param("keep_bootcon", keep_bootcon_setup);
2212 * The console driver calls this routine during kernel initialization
2213 * to register the console printing procedure with printk() and to
2214 * print any messages that were printed by the kernel before the
2215 * console driver was initialized.
2217 * This can happen pretty early during the boot process (because of
2218 * early_printk) - sometimes before setup_arch() completes - be careful
2219 * of what kernel features are used - they may not be initialised yet.
2221 * There are two types of consoles - bootconsoles (early_printk) and
2222 * "real" consoles (everything which is not a bootconsole) which are
2223 * handled differently.
2224 * - Any number of bootconsoles can be registered at any time.
2225 * - As soon as a "real" console is registered, all bootconsoles
2226 * will be unregistered automatically.
2227 * - Once a "real" console is registered, any attempt to register a
2228 * bootconsoles will be rejected
2230 void register_console(struct console *newcon)
2233 unsigned long flags;
2234 struct console *bcon = NULL;
2237 * before we register a new CON_BOOT console, make sure we don't
2238 * already have a valid console
2240 if (console_drivers && newcon->flags & CON_BOOT) {
2241 /* find the last or real console */
2242 for_each_console(bcon) {
2243 if (!(bcon->flags & CON_BOOT)) {
2244 printk(KERN_INFO "Too late to register bootconsole %s%d\n",
2245 newcon->name, newcon->index);
2251 if (console_drivers && console_drivers->flags & CON_BOOT)
2252 bcon = console_drivers;
2254 if (preferred_console < 0 || bcon || !console_drivers)
2255 preferred_console = selected_console;
2257 if (newcon->early_setup)
2258 newcon->early_setup();
2261 * See if we want to use this console driver. If we
2262 * didn't select a console we take the first one
2263 * that registers here.
2265 if (preferred_console < 0) {
2266 if (newcon->index < 0)
2268 if (newcon->setup == NULL ||
2269 newcon->setup(newcon, NULL) == 0) {
2270 newcon->flags |= CON_ENABLED;
2271 if (newcon->device) {
2272 newcon->flags |= CON_CONSDEV;
2273 preferred_console = 0;
2279 * See if this console matches one we selected on
2282 for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0];
2284 if (strcmp(console_cmdline[i].name, newcon->name) != 0)
2286 if (newcon->index >= 0 &&
2287 newcon->index != console_cmdline[i].index)
2289 if (newcon->index < 0)
2290 newcon->index = console_cmdline[i].index;
2291 #ifdef CONFIG_A11Y_BRAILLE_CONSOLE
2292 if (console_cmdline[i].brl_options) {
2293 newcon->flags |= CON_BRL;
2294 braille_register_console(newcon,
2295 console_cmdline[i].index,
2296 console_cmdline[i].options,
2297 console_cmdline[i].brl_options);
2301 if (newcon->setup &&
2302 newcon->setup(newcon, console_cmdline[i].options) != 0)
2304 newcon->flags |= CON_ENABLED;
2305 newcon->index = console_cmdline[i].index;
2306 if (i == selected_console) {
2307 newcon->flags |= CON_CONSDEV;
2308 preferred_console = selected_console;
2313 if (!(newcon->flags & CON_ENABLED))
2317 * If we have a bootconsole, and are switching to a real console,
2318 * don't print everything out again, since when the boot console, and
2319 * the real console are the same physical device, it's annoying to
2320 * see the beginning boot messages twice
2322 if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV))
2323 newcon->flags &= ~CON_PRINTBUFFER;
2326 * Put this console in the list - keep the
2327 * preferred driver at the head of the list.
2330 if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) {
2331 newcon->next = console_drivers;
2332 console_drivers = newcon;
2334 newcon->next->flags &= ~CON_CONSDEV;
2336 newcon->next = console_drivers->next;
2337 console_drivers->next = newcon;
2339 if (newcon->flags & CON_PRINTBUFFER) {
2341 * console_unlock(); will print out the buffered messages
2344 raw_spin_lock_irqsave(&logbuf_lock, flags);
2345 console_seq = syslog_seq;
2346 console_idx = syslog_idx;
2347 console_prev = syslog_prev;
2348 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2350 * We're about to replay the log buffer. Only do this to the
2351 * just-registered console to avoid excessive message spam to
2352 * the already-registered consoles.
2354 exclusive_console = newcon;
2357 console_sysfs_notify();
2360 * By unregistering the bootconsoles after we enable the real console
2361 * we get the "console xxx enabled" message on all the consoles -
2362 * boot consoles, real consoles, etc - this is to ensure that end
2363 * users know there might be something in the kernel's log buffer that
2364 * went to the bootconsole (that they do not see on the real console)
2367 ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) &&
2369 /* we need to iterate through twice, to make sure we print
2370 * everything out, before we unregister the console(s)
2372 printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n",
2373 newcon->name, newcon->index);
2374 for_each_console(bcon)
2375 if (bcon->flags & CON_BOOT)
2376 unregister_console(bcon);
2378 printk(KERN_INFO "%sconsole [%s%d] enabled\n",
2379 (newcon->flags & CON_BOOT) ? "boot" : "" ,
2380 newcon->name, newcon->index);
2383 EXPORT_SYMBOL(register_console);
2385 int unregister_console(struct console *console)
2387 struct console *a, *b;
2390 #ifdef CONFIG_A11Y_BRAILLE_CONSOLE
2391 if (console->flags & CON_BRL)
2392 return braille_unregister_console(console);
2396 if (console_drivers == console) {
2397 console_drivers=console->next;
2399 } else if (console_drivers) {
2400 for (a=console_drivers->next, b=console_drivers ;
2401 a; b=a, a=b->next) {
2411 * If this isn't the last console and it has CON_CONSDEV set, we
2412 * need to set it on the next preferred console.
2414 if (console_drivers != NULL && console->flags & CON_CONSDEV)
2415 console_drivers->flags |= CON_CONSDEV;
2418 console_sysfs_notify();
2421 EXPORT_SYMBOL(unregister_console);
2423 static int __init printk_late_init(void)
2425 struct console *con;
2427 for_each_console(con) {
2428 if (!keep_bootcon && con->flags & CON_BOOT) {
2429 printk(KERN_INFO "turn off boot console %s%d\n",
2430 con->name, con->index);
2431 unregister_console(con);
2434 hotcpu_notifier(console_cpu_notify, 0);
2437 late_initcall(printk_late_init);
2439 #if defined CONFIG_PRINTK
2441 * Delayed printk version, for scheduler-internal messages:
2443 #define PRINTK_BUF_SIZE 512
2445 #define PRINTK_PENDING_WAKEUP 0x01
2446 #define PRINTK_PENDING_SCHED 0x02
2448 static DEFINE_PER_CPU(int, printk_pending);
2449 static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf);
2451 static void wake_up_klogd_work_func(struct irq_work *irq_work)
2453 int pending = __this_cpu_xchg(printk_pending, 0);
2455 if (pending & PRINTK_PENDING_SCHED) {
2456 char *buf = __get_cpu_var(printk_sched_buf);
2457 printk(KERN_WARNING "[sched_delayed] %s", buf);
2460 if (pending & PRINTK_PENDING_WAKEUP)
2461 wake_up_interruptible(&log_wait);
2464 static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
2465 .func = wake_up_klogd_work_func,
2466 .flags = IRQ_WORK_LAZY,
2469 void wake_up_klogd(void)
2472 if (waitqueue_active(&log_wait)) {
2473 this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
2474 irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
2479 int printk_sched(const char *fmt, ...)
2481 unsigned long flags;
2486 local_irq_save(flags);
2487 buf = __get_cpu_var(printk_sched_buf);
2489 va_start(args, fmt);
2490 r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args);
2493 __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED);
2494 irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
2495 local_irq_restore(flags);
2501 * printk rate limiting, lifted from the networking subsystem.
2503 * This enforces a rate limit: not more than 10 kernel messages
2504 * every 5s to make a denial-of-service attack impossible.
2506 DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10);
2508 int __printk_ratelimit(const char *func)
2510 return ___ratelimit(&printk_ratelimit_state, func);
2512 EXPORT_SYMBOL(__printk_ratelimit);
2515 * printk_timed_ratelimit - caller-controlled printk ratelimiting
2516 * @caller_jiffies: pointer to caller's state
2517 * @interval_msecs: minimum interval between prints
2519 * printk_timed_ratelimit() returns true if more than @interval_msecs
2520 * milliseconds have elapsed since the last time printk_timed_ratelimit()
2523 bool printk_timed_ratelimit(unsigned long *caller_jiffies,
2524 unsigned int interval_msecs)
2526 if (*caller_jiffies == 0
2527 || !time_in_range(jiffies, *caller_jiffies,
2529 + msecs_to_jiffies(interval_msecs))) {
2530 *caller_jiffies = jiffies;
2535 EXPORT_SYMBOL(printk_timed_ratelimit);
2537 static DEFINE_SPINLOCK(dump_list_lock);
2538 static LIST_HEAD(dump_list);
2541 * kmsg_dump_register - register a kernel log dumper.
2542 * @dumper: pointer to the kmsg_dumper structure
2544 * Adds a kernel log dumper to the system. The dump callback in the
2545 * structure will be called when the kernel oopses or panics and must be
2546 * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise.
2548 int kmsg_dump_register(struct kmsg_dumper *dumper)
2550 unsigned long flags;
2553 /* The dump callback needs to be set */
2557 spin_lock_irqsave(&dump_list_lock, flags);
2558 /* Don't allow registering multiple times */
2559 if (!dumper->registered) {
2560 dumper->registered = 1;
2561 list_add_tail_rcu(&dumper->list, &dump_list);
2564 spin_unlock_irqrestore(&dump_list_lock, flags);
2568 EXPORT_SYMBOL_GPL(kmsg_dump_register);
2571 * kmsg_dump_unregister - unregister a kmsg dumper.
2572 * @dumper: pointer to the kmsg_dumper structure
2574 * Removes a dump device from the system. Returns zero on success and
2575 * %-EINVAL otherwise.
2577 int kmsg_dump_unregister(struct kmsg_dumper *dumper)
2579 unsigned long flags;
2582 spin_lock_irqsave(&dump_list_lock, flags);
2583 if (dumper->registered) {
2584 dumper->registered = 0;
2585 list_del_rcu(&dumper->list);
2588 spin_unlock_irqrestore(&dump_list_lock, flags);
2593 EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
2595 static bool always_kmsg_dump;
2596 module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
2599 * kmsg_dump - dump kernel log to kernel message dumpers.
2600 * @reason: the reason (oops, panic etc) for dumping
2602 * Call each of the registered dumper's dump() callback, which can
2603 * retrieve the kmsg records with kmsg_dump_get_line() or
2604 * kmsg_dump_get_buffer().
2606 void kmsg_dump(enum kmsg_dump_reason reason)
2608 struct kmsg_dumper *dumper;
2609 unsigned long flags;
2611 if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
2615 list_for_each_entry_rcu(dumper, &dump_list, list) {
2616 if (dumper->max_reason && reason > dumper->max_reason)
2619 /* initialize iterator with data about the stored records */
2620 dumper->active = true;
2622 raw_spin_lock_irqsave(&logbuf_lock, flags);
2623 dumper->cur_seq = clear_seq;
2624 dumper->cur_idx = clear_idx;
2625 dumper->next_seq = log_next_seq;
2626 dumper->next_idx = log_next_idx;
2627 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2629 /* invoke dumper which will iterate over records */
2630 dumper->dump(dumper, reason);
2632 /* reset iterator */
2633 dumper->active = false;
2639 * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
2640 * @dumper: registered kmsg dumper
2641 * @syslog: include the "<4>" prefixes
2642 * @line: buffer to copy the line to
2643 * @size: maximum size of the buffer
2644 * @len: length of line placed into buffer
2646 * Start at the beginning of the kmsg buffer, with the oldest kmsg
2647 * record, and copy one record into the provided buffer.
2649 * Consecutive calls will return the next available record moving
2650 * towards the end of the buffer with the youngest messages.
2652 * A return value of FALSE indicates that there are no more records to
2655 * The function is similar to kmsg_dump_get_line(), but grabs no locks.
2657 bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
2658 char *line, size_t size, size_t *len)
2664 if (!dumper->active)
2667 if (dumper->cur_seq < log_first_seq) {
2668 /* messages are gone, move to first available one */
2669 dumper->cur_seq = log_first_seq;
2670 dumper->cur_idx = log_first_idx;
2674 if (dumper->cur_seq >= log_next_seq)
2677 msg = log_from_idx(dumper->cur_idx);
2678 l = msg_print_text(msg, 0, syslog, line, size);
2680 dumper->cur_idx = log_next(dumper->cur_idx);
2690 * kmsg_dump_get_line - retrieve one kmsg log line
2691 * @dumper: registered kmsg dumper
2692 * @syslog: include the "<4>" prefixes
2693 * @line: buffer to copy the line to
2694 * @size: maximum size of the buffer
2695 * @len: length of line placed into buffer
2697 * Start at the beginning of the kmsg buffer, with the oldest kmsg
2698 * record, and copy one record into the provided buffer.
2700 * Consecutive calls will return the next available record moving
2701 * towards the end of the buffer with the youngest messages.
2703 * A return value of FALSE indicates that there are no more records to
2706 bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
2707 char *line, size_t size, size_t *len)
2709 unsigned long flags;
2712 raw_spin_lock_irqsave(&logbuf_lock, flags);
2713 ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
2714 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2718 EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
2721 * kmsg_dump_get_buffer - copy kmsg log lines
2722 * @dumper: registered kmsg dumper
2723 * @syslog: include the "<4>" prefixes
2724 * @buf: buffer to copy the line to
2725 * @size: maximum size of the buffer
2726 * @len: length of line placed into buffer
2728 * Start at the end of the kmsg buffer and fill the provided buffer
2729 * with as many of the the *youngest* kmsg records that fit into it.
2730 * If the buffer is large enough, all available kmsg records will be
2731 * copied with a single call.
2733 * Consecutive calls will fill the buffer with the next block of
2734 * available older records, not including the earlier retrieved ones.
2736 * A return value of FALSE indicates that there are no more records to
2739 bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
2740 char *buf, size_t size, size_t *len)
2742 unsigned long flags;
2747 enum log_flags prev;
2751 if (!dumper->active)
2754 raw_spin_lock_irqsave(&logbuf_lock, flags);
2755 if (dumper->cur_seq < log_first_seq) {
2756 /* messages are gone, move to first available one */
2757 dumper->cur_seq = log_first_seq;
2758 dumper->cur_idx = log_first_idx;
2762 if (dumper->cur_seq >= dumper->next_seq) {
2763 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2767 /* calculate length of entire buffer */
2768 seq = dumper->cur_seq;
2769 idx = dumper->cur_idx;
2771 while (seq < dumper->next_seq) {
2772 struct log *msg = log_from_idx(idx);
2774 l += msg_print_text(msg, prev, true, NULL, 0);
2775 idx = log_next(idx);
2780 /* move first record forward until length fits into the buffer */
2781 seq = dumper->cur_seq;
2782 idx = dumper->cur_idx;
2784 while (l > size && seq < dumper->next_seq) {
2785 struct log *msg = log_from_idx(idx);
2787 l -= msg_print_text(msg, prev, true, NULL, 0);
2788 idx = log_next(idx);
2793 /* last message in next interation */
2799 while (seq < dumper->next_seq) {
2800 struct log *msg = log_from_idx(idx);
2802 l += msg_print_text(msg, prev, syslog, buf + l, size - l);
2803 idx = log_next(idx);
2808 dumper->next_seq = next_seq;
2809 dumper->next_idx = next_idx;
2811 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2817 EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
2820 * kmsg_dump_rewind_nolock - reset the interator (unlocked version)
2821 * @dumper: registered kmsg dumper
2823 * Reset the dumper's iterator so that kmsg_dump_get_line() and
2824 * kmsg_dump_get_buffer() can be called again and used multiple
2825 * times within the same dumper.dump() callback.
2827 * The function is similar to kmsg_dump_rewind(), but grabs no locks.
2829 void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
2831 dumper->cur_seq = clear_seq;
2832 dumper->cur_idx = clear_idx;
2833 dumper->next_seq = log_next_seq;
2834 dumper->next_idx = log_next_idx;
2838 * kmsg_dump_rewind - reset the interator
2839 * @dumper: registered kmsg dumper
2841 * Reset the dumper's iterator so that kmsg_dump_get_line() and
2842 * kmsg_dump_get_buffer() can be called again and used multiple
2843 * times within the same dumper.dump() callback.
2845 void kmsg_dump_rewind(struct kmsg_dumper *dumper)
2847 unsigned long flags;
2849 raw_spin_lock_irqsave(&logbuf_lock, flags);
2850 kmsg_dump_rewind_nolock(dumper);
2851 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2853 EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
2855 static char dump_stack_arch_desc_str[128];
2858 * dump_stack_set_arch_desc - set arch-specific str to show with task dumps
2859 * @fmt: printf-style format string
2860 * @...: arguments for the format string
2862 * The configured string will be printed right after utsname during task
2863 * dumps. Usually used to add arch-specific system identifiers. If an
2864 * arch wants to make use of such an ID string, it should initialize this
2865 * as soon as possible during boot.
2867 void __init dump_stack_set_arch_desc(const char *fmt, ...)
2871 va_start(args, fmt);
2872 vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
2878 * dump_stack_print_info - print generic debug info for dump_stack()
2879 * @log_lvl: log level
2881 * Arch-specific dump_stack() implementations can use this function to
2882 * print out the same debug information as the generic dump_stack().
2884 void dump_stack_print_info(const char *log_lvl)
2886 printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n",
2887 log_lvl, raw_smp_processor_id(), current->pid, current->comm,
2888 print_tainted(), init_utsname()->release,
2889 (int)strcspn(init_utsname()->version, " "),
2890 init_utsname()->version);
2892 if (dump_stack_arch_desc_str[0] != '\0')
2893 printk("%sHardware name: %s\n",
2894 log_lvl, dump_stack_arch_desc_str);
2896 print_worker_info(log_lvl, current);
2900 * show_regs_print_info - print generic debug info for show_regs()
2901 * @log_lvl: log level
2903 * show_regs() implementations can use this function to print out generic
2904 * debug information.
2906 void show_regs_print_info(const char *log_lvl)
2908 dump_stack_print_info(log_lvl);
2910 printk("%stask: %p ti: %p task.ti: %p\n",
2911 log_lvl, current, current_thread_info(),
2912 task_thread_info(current));