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 #ifdef CONFIG_EARLY_PRINTK_DIRECT
55 extern void printascii(char *);
58 /* printk's without a loglevel use this.. */
59 #define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL
61 /* We show everything that is MORE important than this.. */
62 #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */
63 #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */
65 int console_printk[4] = {
66 DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */
67 DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */
68 MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */
69 DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */
73 * Low level drivers may need that to know if they can schedule in
74 * their unblank() callback or not. So let's export it.
77 EXPORT_SYMBOL(oops_in_progress);
80 * console_sem protects the console_drivers list, and also
81 * provides serialisation for access to the entire console
84 static DEFINE_SEMAPHORE(console_sem);
85 struct console *console_drivers;
86 EXPORT_SYMBOL_GPL(console_drivers);
89 static struct lockdep_map console_lock_dep_map = {
90 .name = "console_lock"
95 * This is used for debugging the mess that is the VT code by
96 * keeping track if we have the console semaphore held. It's
97 * definitely not the perfect debug tool (we don't know if _WE_
98 * hold it are racing, but it helps tracking those weird code
99 * path in the console code where we end up in places I want
100 * locked without the console sempahore held
102 static int console_locked, console_suspended;
105 * If exclusive_console is non-NULL then only this console is to be printed to.
107 static struct console *exclusive_console;
110 * Array of consoles built from command line options (console=)
112 struct console_cmdline
114 char name[8]; /* Name of the driver */
115 int index; /* Minor dev. to use */
116 char *options; /* Options for the driver */
117 #ifdef CONFIG_A11Y_BRAILLE_CONSOLE
118 char *brl_options; /* Options for braille driver */
122 #define MAX_CMDLINECONSOLES 8
124 static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES];
125 static int selected_console = -1;
126 static int preferred_console = -1;
127 int console_set_on_cmdline;
128 EXPORT_SYMBOL(console_set_on_cmdline);
130 /* Flag: console code may call schedule() */
131 static int console_may_schedule;
134 * The printk log buffer consists of a chain of concatenated variable
135 * length records. Every record starts with a record header, containing
136 * the overall length of the record.
138 * The heads to the first and last entry in the buffer, as well as the
139 * sequence numbers of these both entries are maintained when messages
142 * If the heads indicate available messages, the length in the header
143 * tells the start next message. A length == 0 for the next message
144 * indicates a wrap-around to the beginning of the buffer.
146 * Every record carries the monotonic timestamp in microseconds, as well as
147 * the standard userspace syslog level and syslog facility. The usual
148 * kernel messages use LOG_KERN; userspace-injected messages always carry
149 * a matching syslog facility, by default LOG_USER. The origin of every
150 * message can be reliably determined that way.
152 * The human readable log message directly follows the message header. The
153 * length of the message text is stored in the header, the stored message
156 * Optionally, a message can carry a dictionary of properties (key/value pairs),
157 * to provide userspace with a machine-readable message context.
159 * Examples for well-defined, commonly used property names are:
160 * DEVICE=b12:8 device identifier
164 * +sound:card0 subsystem:devname
165 * SUBSYSTEM=pci driver-core subsystem name
167 * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value
168 * follows directly after a '=' character. Every property is terminated by
169 * a '\0' character. The last property is not terminated.
171 * Example of a message structure:
172 * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec
173 * 0008 34 00 record is 52 bytes long
174 * 000a 0b 00 text is 11 bytes long
175 * 000c 1f 00 dictionary is 23 bytes long
176 * 000e 03 00 LOG_KERN (facility) LOG_ERR (level)
177 * 0010 69 74 27 73 20 61 20 6c "it's a l"
179 * 001b 44 45 56 49 43 "DEVIC"
180 * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D"
181 * 52 49 56 45 52 3d 62 75 "RIVER=bu"
183 * 0032 00 00 00 padding to next message header
185 * The 'struct log' buffer header must never be directly exported to
186 * userspace, it is a kernel-private implementation detail that might
187 * need to be changed in the future, when the requirements change.
189 * /dev/kmsg exports the structured data in the following line format:
190 * "level,sequnum,timestamp;<message text>\n"
192 * The optional key/value pairs are attached as continuation lines starting
193 * with a space character and terminated by a newline. All possible
194 * non-prinatable characters are escaped in the "\xff" notation.
196 * Users of the export format should ignore possible additional values
197 * separated by ',', and find the message after the ';' character.
201 LOG_NOCONS = 1, /* already flushed, do not print to console */
202 LOG_NEWLINE = 2, /* text ended with a newline */
203 LOG_PREFIX = 4, /* text started with a prefix */
204 LOG_CONT = 8, /* text is a fragment of a continuation line */
208 u64 ts_nsec; /* timestamp in nanoseconds */
209 u16 len; /* length of entire record */
210 u16 text_len; /* length of text buffer */
211 u16 dict_len; /* length of dictionary buffer */
212 u8 facility; /* syslog facility */
213 u8 flags:5; /* internal record flags */
214 u8 level:3; /* syslog level */
218 * The logbuf_lock protects kmsg buffer, indices, counters. It is also
219 * used in interesting ways to provide interlocking in console_unlock();
221 static DEFINE_RAW_SPINLOCK(logbuf_lock);
224 DECLARE_WAIT_QUEUE_HEAD(log_wait);
225 /* the next printk record to read by syslog(READ) or /proc/kmsg */
226 static u64 syslog_seq;
227 static u32 syslog_idx;
228 static enum log_flags syslog_prev;
229 static size_t syslog_partial;
231 /* index and sequence number of the first record stored in the buffer */
232 static u64 log_first_seq;
233 static u32 log_first_idx;
235 /* index and sequence number of the next record to store in the buffer */
236 static u64 log_next_seq;
237 static u32 log_next_idx;
239 /* the next printk record to write to the console */
240 static u64 console_seq;
241 static u32 console_idx;
242 static enum log_flags console_prev;
244 /* the next printk record to read after the last 'clear' command */
245 static u64 clear_seq;
246 static u32 clear_idx;
248 #define PREFIX_MAX 32
249 #define LOG_LINE_MAX 1024 - PREFIX_MAX
252 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
255 #define LOG_ALIGN __alignof__(struct log)
257 #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
258 static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
259 static char *log_buf = __log_buf;
260 static u32 log_buf_len = __LOG_BUF_LEN;
262 /* cpu currently holding logbuf_lock */
263 static volatile unsigned int logbuf_cpu = UINT_MAX;
265 /* human readable text of the record */
266 static char *log_text(const struct log *msg)
268 return (char *)msg + sizeof(struct log);
271 /* optional key/value pair dictionary attached to the record */
272 static char *log_dict(const struct log *msg)
274 return (char *)msg + sizeof(struct log) + msg->text_len;
277 /* get record by index; idx must point to valid msg */
278 static struct log *log_from_idx(u32 idx)
280 struct log *msg = (struct log *)(log_buf + idx);
283 * A length == 0 record is the end of buffer marker. Wrap around and
284 * read the message at the start of the buffer.
287 return (struct log *)log_buf;
291 /* get next record; idx must point to valid msg */
292 static u32 log_next(u32 idx)
294 struct log *msg = (struct log *)(log_buf + idx);
296 /* length == 0 indicates the end of the buffer; wrap */
298 * A length == 0 record is the end of buffer marker. Wrap around and
299 * read the message at the start of the buffer as *this* one, and
300 * return the one after that.
303 msg = (struct log *)log_buf;
306 return idx + msg->len;
309 /* insert record into the buffer, discard old ones, update heads */
310 static void log_store(int facility, int level,
311 enum log_flags flags, u64 ts_nsec,
312 const char *dict, u16 dict_len,
313 const char *text, u16 text_len)
318 /* number of '\0' padding bytes to next message */
319 size = sizeof(struct log) + text_len + dict_len;
320 pad_len = (-size) & (LOG_ALIGN - 1);
323 while (log_first_seq < log_next_seq) {
326 if (log_next_idx > log_first_idx)
327 free = max(log_buf_len - log_next_idx, log_first_idx);
329 free = log_first_idx - log_next_idx;
331 if (free > size + sizeof(struct log))
334 /* drop old messages until we have enough contiuous space */
335 log_first_idx = log_next(log_first_idx);
339 if (log_next_idx + size + sizeof(struct log) >= log_buf_len) {
341 * This message + an additional empty header does not fit
342 * at the end of the buffer. Add an empty header with len == 0
343 * to signify a wrap around.
345 memset(log_buf + log_next_idx, 0, sizeof(struct log));
350 msg = (struct log *)(log_buf + log_next_idx);
351 memcpy(log_text(msg), text, text_len);
352 msg->text_len = text_len;
353 memcpy(log_dict(msg), dict, dict_len);
354 msg->dict_len = dict_len;
355 msg->facility = facility;
356 msg->level = level & 7;
357 msg->flags = flags & 0x1f;
359 msg->ts_nsec = ts_nsec;
361 msg->ts_nsec = local_clock();
362 memset(log_dict(msg) + dict_len, 0, pad_len);
363 msg->len = sizeof(struct log) + text_len + dict_len + pad_len;
366 log_next_idx += msg->len;
370 #ifdef CONFIG_SECURITY_DMESG_RESTRICT
371 int dmesg_restrict = 1;
376 static int syslog_action_restricted(int type)
381 * Unless restricted, we allow "read all" and "get buffer size"
384 return type != SYSLOG_ACTION_READ_ALL &&
385 type != SYSLOG_ACTION_SIZE_BUFFER;
388 static int check_syslog_permissions(int type, bool from_file)
391 * If this is from /proc/kmsg and we've already opened it, then we've
392 * already done the capabilities checks at open time.
394 if (from_file && type != SYSLOG_ACTION_OPEN)
397 if (syslog_action_restricted(type)) {
398 if (capable(CAP_SYSLOG))
401 * For historical reasons, accept CAP_SYS_ADMIN too, with
404 if (capable(CAP_SYS_ADMIN)) {
405 pr_warn_once("%s (%d): Attempt to access syslog with "
406 "CAP_SYS_ADMIN but no CAP_SYSLOG "
408 current->comm, task_pid_nr(current));
413 return security_syslog(type);
417 /* /dev/kmsg - userspace message inject/listen interface */
418 struct devkmsg_user {
426 static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv,
427 unsigned long count, loff_t pos)
431 int level = default_message_loglevel;
432 int facility = 1; /* LOG_USER */
433 size_t len = iov_length(iv, count);
436 if (len > LOG_LINE_MAX)
438 buf = kmalloc(len+1, GFP_KERNEL);
443 for (i = 0; i < count; i++) {
444 if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) {
448 line += iv[i].iov_len;
452 * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace
453 * the decimal value represents 32bit, the lower 3 bit are the log
454 * level, the rest are the log facility.
456 * If no prefix or no userspace facility is specified, we
457 * enforce LOG_USER, to be able to reliably distinguish
458 * kernel-generated messages from userspace-injected ones.
461 if (line[0] == '<') {
464 i = simple_strtoul(line+1, &endp, 10);
465 if (endp && endp[0] == '>') {
476 printk_emit(facility, level, NULL, 0, "%s", line);
482 static ssize_t devkmsg_read(struct file *file, char __user *buf,
483 size_t count, loff_t *ppos)
485 struct devkmsg_user *user = file->private_data;
496 ret = mutex_lock_interruptible(&user->lock);
499 raw_spin_lock_irq(&logbuf_lock);
500 while (user->seq == log_next_seq) {
501 if (file->f_flags & O_NONBLOCK) {
503 raw_spin_unlock_irq(&logbuf_lock);
507 raw_spin_unlock_irq(&logbuf_lock);
508 ret = wait_event_interruptible(log_wait,
509 user->seq != log_next_seq);
512 raw_spin_lock_irq(&logbuf_lock);
515 if (user->seq < log_first_seq) {
516 /* our last seen message is gone, return error and reset */
517 user->idx = log_first_idx;
518 user->seq = log_first_seq;
520 raw_spin_unlock_irq(&logbuf_lock);
524 msg = log_from_idx(user->idx);
525 ts_usec = msg->ts_nsec;
526 do_div(ts_usec, 1000);
529 * If we couldn't merge continuation line fragments during the print,
530 * export the stored flags to allow an optional external merge of the
531 * records. Merging the records isn't always neccessarily correct, like
532 * when we hit a race during printing. In most cases though, it produces
533 * better readable output. 'c' in the record flags mark the first
534 * fragment of a line, '+' the following.
536 if (msg->flags & LOG_CONT && !(user->prev & LOG_CONT))
538 else if ((msg->flags & LOG_CONT) ||
539 ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)))
542 len = sprintf(user->buf, "%u,%llu,%llu,%c;",
543 (msg->facility << 3) | msg->level,
544 user->seq, ts_usec, cont);
545 user->prev = msg->flags;
547 /* escape non-printable characters */
548 for (i = 0; i < msg->text_len; i++) {
549 unsigned char c = log_text(msg)[i];
551 if (c < ' ' || c >= 127 || c == '\\')
552 len += sprintf(user->buf + len, "\\x%02x", c);
554 user->buf[len++] = c;
556 user->buf[len++] = '\n';
561 for (i = 0; i < msg->dict_len; i++) {
562 unsigned char c = log_dict(msg)[i];
565 user->buf[len++] = ' ';
570 user->buf[len++] = '\n';
575 if (c < ' ' || c >= 127 || c == '\\') {
576 len += sprintf(user->buf + len, "\\x%02x", c);
580 user->buf[len++] = c;
582 user->buf[len++] = '\n';
585 user->idx = log_next(user->idx);
587 raw_spin_unlock_irq(&logbuf_lock);
594 if (copy_to_user(buf, user->buf, len)) {
600 mutex_unlock(&user->lock);
604 static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
606 struct devkmsg_user *user = file->private_data;
614 raw_spin_lock_irq(&logbuf_lock);
617 /* the first record */
618 user->idx = log_first_idx;
619 user->seq = log_first_seq;
623 * The first record after the last SYSLOG_ACTION_CLEAR,
624 * like issued by 'dmesg -c'. Reading /dev/kmsg itself
625 * changes no global state, and does not clear anything.
627 user->idx = clear_idx;
628 user->seq = clear_seq;
631 /* after the last record */
632 user->idx = log_next_idx;
633 user->seq = log_next_seq;
638 raw_spin_unlock_irq(&logbuf_lock);
642 static unsigned int devkmsg_poll(struct file *file, poll_table *wait)
644 struct devkmsg_user *user = file->private_data;
648 return POLLERR|POLLNVAL;
650 poll_wait(file, &log_wait, wait);
652 raw_spin_lock_irq(&logbuf_lock);
653 if (user->seq < log_next_seq) {
654 /* return error when data has vanished underneath us */
655 if (user->seq < log_first_seq)
656 ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI;
658 ret = POLLIN|POLLRDNORM;
660 raw_spin_unlock_irq(&logbuf_lock);
665 static int devkmsg_open(struct inode *inode, struct file *file)
667 struct devkmsg_user *user;
670 /* write-only does not need any file context */
671 if ((file->f_flags & O_ACCMODE) == O_WRONLY)
674 err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
679 user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL);
683 mutex_init(&user->lock);
685 raw_spin_lock_irq(&logbuf_lock);
686 user->idx = log_first_idx;
687 user->seq = log_first_seq;
688 raw_spin_unlock_irq(&logbuf_lock);
690 file->private_data = user;
694 static int devkmsg_release(struct inode *inode, struct file *file)
696 struct devkmsg_user *user = file->private_data;
701 mutex_destroy(&user->lock);
706 const struct file_operations kmsg_fops = {
707 .open = devkmsg_open,
708 .read = devkmsg_read,
709 .aio_write = devkmsg_writev,
710 .llseek = devkmsg_llseek,
711 .poll = devkmsg_poll,
712 .release = devkmsg_release,
717 * This appends the listed symbols to /proc/vmcoreinfo
719 * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to
720 * obtain access to symbols that are otherwise very difficult to locate. These
721 * symbols are specifically used so that utilities can access and extract the
722 * dmesg log from a vmcore file after a crash.
724 void log_buf_kexec_setup(void)
726 VMCOREINFO_SYMBOL(log_buf);
727 VMCOREINFO_SYMBOL(log_buf_len);
728 VMCOREINFO_SYMBOL(log_first_idx);
729 VMCOREINFO_SYMBOL(log_next_idx);
731 * Export struct log size and field offsets. User space tools can
732 * parse it and detect any changes to structure down the line.
734 VMCOREINFO_STRUCT_SIZE(log);
735 VMCOREINFO_OFFSET(log, ts_nsec);
736 VMCOREINFO_OFFSET(log, len);
737 VMCOREINFO_OFFSET(log, text_len);
738 VMCOREINFO_OFFSET(log, dict_len);
742 /* requested log_buf_len from kernel cmdline */
743 static unsigned long __initdata new_log_buf_len;
745 /* save requested log_buf_len since it's too early to process it */
746 static int __init log_buf_len_setup(char *str)
748 unsigned size = memparse(str, &str);
751 size = roundup_pow_of_two(size);
752 if (size > log_buf_len)
753 new_log_buf_len = size;
757 early_param("log_buf_len", log_buf_len_setup);
759 void __init setup_log_buf(int early)
765 if (!new_log_buf_len)
771 mem = memblock_alloc(new_log_buf_len, PAGE_SIZE);
774 new_log_buf = __va(mem);
776 new_log_buf = alloc_bootmem_nopanic(new_log_buf_len);
779 if (unlikely(!new_log_buf)) {
780 pr_err("log_buf_len: %ld bytes not available\n",
785 raw_spin_lock_irqsave(&logbuf_lock, flags);
786 log_buf_len = new_log_buf_len;
787 log_buf = new_log_buf;
789 free = __LOG_BUF_LEN - log_next_idx;
790 memcpy(log_buf, __log_buf, __LOG_BUF_LEN);
791 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
793 pr_info("log_buf_len: %d\n", log_buf_len);
794 pr_info("early log buf free: %d(%d%%)\n",
795 free, (free * 100) / __LOG_BUF_LEN);
798 static bool __read_mostly ignore_loglevel;
800 static int __init ignore_loglevel_setup(char *str)
803 printk(KERN_INFO "debug: ignoring loglevel setting.\n");
808 early_param("ignore_loglevel", ignore_loglevel_setup);
809 module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR);
810 MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
811 "print all kernel messages to the console.");
813 #ifdef CONFIG_BOOT_PRINTK_DELAY
815 static int boot_delay; /* msecs delay after each printk during bootup */
816 static unsigned long long loops_per_msec; /* based on boot_delay */
818 static int __init boot_delay_setup(char *str)
822 lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */
823 loops_per_msec = (unsigned long long)lpj / 1000 * HZ;
825 get_option(&str, &boot_delay);
826 if (boot_delay > 10 * 1000)
829 pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, "
830 "HZ: %d, loops_per_msec: %llu\n",
831 boot_delay, preset_lpj, lpj, HZ, loops_per_msec);
834 __setup("boot_delay=", boot_delay_setup);
836 static void boot_delay_msec(int level)
838 unsigned long long k;
839 unsigned long timeout;
841 if ((boot_delay == 0 || system_state != SYSTEM_BOOTING)
842 || (level >= console_loglevel && !ignore_loglevel)) {
846 k = (unsigned long long)loops_per_msec * boot_delay;
848 timeout = jiffies + msecs_to_jiffies(boot_delay);
853 * use (volatile) jiffies to prevent
854 * compiler reduction; loop termination via jiffies
855 * is secondary and may or may not happen.
857 if (time_after(jiffies, timeout))
859 touch_nmi_watchdog();
863 static inline void boot_delay_msec(int level)
868 #if defined(CONFIG_PRINTK_TIME)
869 static bool printk_time = 1;
871 static bool printk_time;
873 module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
875 static size_t print_time(u64 ts, char *buf)
877 unsigned long rem_nsec;
882 rem_nsec = do_div(ts, 1000000000);
885 return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts);
887 return sprintf(buf, "[%5lu.%06lu] ",
888 (unsigned long)ts, rem_nsec / 1000);
891 static size_t print_prefix(const struct log *msg, bool syslog, char *buf)
894 unsigned int prefix = (msg->facility << 3) | msg->level;
898 len += sprintf(buf, "<%u>", prefix);
903 else if (prefix > 99)
910 len += print_time(msg->ts_nsec, buf ? buf + len : NULL);
914 static size_t msg_print_text(const struct log *msg, enum log_flags prev,
915 bool syslog, char *buf, size_t size)
917 const char *text = log_text(msg);
918 size_t text_size = msg->text_len;
923 if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))
926 if (msg->flags & LOG_CONT) {
927 if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE))
930 if (!(msg->flags & LOG_NEWLINE))
935 const char *next = memchr(text, '\n', text_size);
939 text_len = next - text;
941 text_size -= next - text;
943 text_len = text_size;
947 if (print_prefix(msg, syslog, NULL) +
948 text_len + 1 >= size - len)
952 len += print_prefix(msg, syslog, buf + len);
953 memcpy(buf + len, text, text_len);
958 /* SYSLOG_ACTION_* buffer size only calculation */
960 len += print_prefix(msg, syslog, NULL);
973 static int syslog_print(char __user *buf, int size)
979 text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
987 raw_spin_lock_irq(&logbuf_lock);
988 if (syslog_seq < log_first_seq) {
989 /* messages are gone, move to first one */
990 syslog_seq = log_first_seq;
991 syslog_idx = log_first_idx;
995 if (syslog_seq == log_next_seq) {
996 raw_spin_unlock_irq(&logbuf_lock);
1000 skip = syslog_partial;
1001 msg = log_from_idx(syslog_idx);
1002 n = msg_print_text(msg, syslog_prev, true, text,
1003 LOG_LINE_MAX + PREFIX_MAX);
1004 if (n - syslog_partial <= size) {
1005 /* message fits into buffer, move forward */
1006 syslog_idx = log_next(syslog_idx);
1008 syslog_prev = msg->flags;
1009 n -= syslog_partial;
1012 /* partial read(), remember position */
1014 syslog_partial += n;
1017 raw_spin_unlock_irq(&logbuf_lock);
1022 if (copy_to_user(buf, text + skip, n)) {
1037 static int syslog_print_all(char __user *buf, int size, bool clear)
1042 text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
1046 raw_spin_lock_irq(&logbuf_lock);
1051 enum log_flags prev;
1053 if (clear_seq < log_first_seq) {
1054 /* messages are gone, move to first available one */
1055 clear_seq = log_first_seq;
1056 clear_idx = log_first_idx;
1060 * Find first record that fits, including all following records,
1061 * into the user-provided buffer for this dump.
1066 while (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 /* move first record forward until length fits into the buffer */
1079 while (len > size && seq < log_next_seq) {
1080 struct log *msg = log_from_idx(idx);
1082 len -= msg_print_text(msg, prev, true, NULL, 0);
1084 idx = log_next(idx);
1088 /* last message fitting into this dump */
1089 next_seq = log_next_seq;
1093 while (len >= 0 && seq < next_seq) {
1094 struct log *msg = log_from_idx(idx);
1097 textlen = msg_print_text(msg, prev, true, text,
1098 LOG_LINE_MAX + PREFIX_MAX);
1103 idx = log_next(idx);
1107 raw_spin_unlock_irq(&logbuf_lock);
1108 if (copy_to_user(buf + len, text, textlen))
1112 raw_spin_lock_irq(&logbuf_lock);
1114 if (seq < log_first_seq) {
1115 /* messages are gone, move to next one */
1116 seq = log_first_seq;
1117 idx = log_first_idx;
1124 clear_seq = log_next_seq;
1125 clear_idx = log_next_idx;
1127 raw_spin_unlock_irq(&logbuf_lock);
1133 int do_syslog(int type, char __user *buf, int len, bool from_file)
1136 static int saved_console_loglevel = -1;
1139 error = check_syslog_permissions(type, from_file);
1143 error = security_syslog(type);
1148 case SYSLOG_ACTION_CLOSE: /* Close log */
1150 case SYSLOG_ACTION_OPEN: /* Open log */
1152 case SYSLOG_ACTION_READ: /* Read from log */
1154 if (!buf || len < 0)
1159 if (!access_ok(VERIFY_WRITE, buf, len)) {
1163 error = wait_event_interruptible(log_wait,
1164 syslog_seq != log_next_seq);
1167 error = syslog_print(buf, len);
1169 /* Read/clear last kernel messages */
1170 case SYSLOG_ACTION_READ_CLEAR:
1173 /* Read last kernel messages */
1174 case SYSLOG_ACTION_READ_ALL:
1176 if (!buf || len < 0)
1181 if (!access_ok(VERIFY_WRITE, buf, len)) {
1185 error = syslog_print_all(buf, len, clear);
1187 /* Clear ring buffer */
1188 case SYSLOG_ACTION_CLEAR:
1189 syslog_print_all(NULL, 0, true);
1191 /* Disable logging to console */
1192 case SYSLOG_ACTION_CONSOLE_OFF:
1193 if (saved_console_loglevel == -1)
1194 saved_console_loglevel = console_loglevel;
1195 console_loglevel = minimum_console_loglevel;
1197 /* Enable logging to console */
1198 case SYSLOG_ACTION_CONSOLE_ON:
1199 if (saved_console_loglevel != -1) {
1200 console_loglevel = saved_console_loglevel;
1201 saved_console_loglevel = -1;
1204 /* Set level of messages printed to console */
1205 case SYSLOG_ACTION_CONSOLE_LEVEL:
1207 if (len < 1 || len > 8)
1209 if (len < minimum_console_loglevel)
1210 len = minimum_console_loglevel;
1211 console_loglevel = len;
1212 /* Implicitly re-enable logging to console */
1213 saved_console_loglevel = -1;
1216 /* Number of chars in the log buffer */
1217 case SYSLOG_ACTION_SIZE_UNREAD:
1218 raw_spin_lock_irq(&logbuf_lock);
1219 if (syslog_seq < log_first_seq) {
1220 /* messages are gone, move to first one */
1221 syslog_seq = log_first_seq;
1222 syslog_idx = log_first_idx;
1228 * Short-cut for poll(/"proc/kmsg") which simply checks
1229 * for pending data, not the size; return the count of
1230 * records, not the length.
1232 error = log_next_idx - syslog_idx;
1234 u64 seq = syslog_seq;
1235 u32 idx = syslog_idx;
1236 enum log_flags prev = syslog_prev;
1239 while (seq < log_next_seq) {
1240 struct log *msg = log_from_idx(idx);
1242 error += msg_print_text(msg, prev, true, NULL, 0);
1243 idx = log_next(idx);
1247 error -= syslog_partial;
1249 raw_spin_unlock_irq(&logbuf_lock);
1251 /* Size of the log buffer */
1252 case SYSLOG_ACTION_SIZE_BUFFER:
1253 error = log_buf_len;
1263 SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
1265 return do_syslog(type, buf, len, SYSLOG_FROM_READER);
1269 * Call the console drivers, asking them to write out
1270 * log_buf[start] to log_buf[end - 1].
1271 * The console_lock must be held.
1273 static void call_console_drivers(int level, const char *text, size_t len)
1275 struct console *con;
1277 trace_console(text, len);
1279 if (level >= console_loglevel && !ignore_loglevel)
1281 if (!console_drivers)
1284 for_each_console(con) {
1285 if (exclusive_console && con != exclusive_console)
1287 if (!(con->flags & CON_ENABLED))
1291 if (!cpu_online(smp_processor_id()) &&
1292 !(con->flags & CON_ANYTIME))
1294 con->write(con, text, len);
1299 * Zap console related locks when oopsing. Only zap at most once
1300 * every 10 seconds, to leave time for slow consoles to print a
1303 static void zap_locks(void)
1305 static unsigned long oops_timestamp;
1307 if (time_after_eq(jiffies, oops_timestamp) &&
1308 !time_after(jiffies, oops_timestamp + 30 * HZ))
1311 oops_timestamp = jiffies;
1314 /* If a crash is occurring, make sure we can't deadlock */
1315 raw_spin_lock_init(&logbuf_lock);
1316 /* And make sure that we print immediately */
1317 sema_init(&console_sem, 1);
1320 /* Check if we have any console registered that can be called early in boot. */
1321 static int have_callable_console(void)
1323 struct console *con;
1325 for_each_console(con)
1326 if (con->flags & CON_ANYTIME)
1333 * Can we actually use the console at this time on this cpu?
1335 * Console drivers may assume that per-cpu resources have
1336 * been allocated. So unless they're explicitly marked as
1337 * being able to cope (CON_ANYTIME) don't call them until
1338 * this CPU is officially up.
1340 static inline int can_use_console(unsigned int cpu)
1342 return cpu_online(cpu) || have_callable_console();
1346 * Try to get console ownership to actually show the kernel
1347 * messages from a 'printk'. Return true (and with the
1348 * console_lock held, and 'console_locked' set) if it
1349 * is successful, false otherwise.
1351 * This gets called with the 'logbuf_lock' spinlock held and
1352 * interrupts disabled. It should return with 'lockbuf_lock'
1353 * released but interrupts still disabled.
1355 static int console_trylock_for_printk(unsigned int cpu)
1356 __releases(&logbuf_lock)
1358 int retval = 0, wake = 0;
1360 if (console_trylock()) {
1364 * If we can't use the console, we need to release
1365 * the console semaphore by hand to avoid flushing
1366 * the buffer. We need to hold the console semaphore
1367 * in order to do this test safely.
1369 if (!can_use_console(cpu)) {
1375 logbuf_cpu = UINT_MAX;
1378 raw_spin_unlock(&logbuf_lock);
1382 int printk_delay_msec __read_mostly;
1384 static inline void printk_delay(void)
1386 if (unlikely(printk_delay_msec)) {
1387 int m = printk_delay_msec;
1391 touch_nmi_watchdog();
1397 * Continuation lines are buffered, and not committed to the record buffer
1398 * until the line is complete, or a race forces it. The line fragments
1399 * though, are printed immediately to the consoles to ensure everything has
1400 * reached the console in case of a kernel crash.
1402 static struct cont {
1403 char buf[LOG_LINE_MAX];
1404 size_t len; /* length == 0 means unused buffer */
1405 size_t cons; /* bytes written to console */
1406 struct task_struct *owner; /* task of first print*/
1407 u64 ts_nsec; /* time of first print */
1408 u8 level; /* log level of first message */
1409 u8 facility; /* log level of first message */
1410 enum log_flags flags; /* prefix, newline flags */
1411 bool flushed:1; /* buffer sealed and committed */
1414 static void cont_flush(enum log_flags flags)
1423 * If a fragment of this line was directly flushed to the
1424 * console; wait for the console to pick up the rest of the
1425 * line. LOG_NOCONS suppresses a duplicated output.
1427 log_store(cont.facility, cont.level, flags | LOG_NOCONS,
1428 cont.ts_nsec, NULL, 0, cont.buf, cont.len);
1430 cont.flushed = true;
1433 * If no fragment of this line ever reached the console,
1434 * just submit it to the store and free the buffer.
1436 log_store(cont.facility, cont.level, flags, 0,
1437 NULL, 0, cont.buf, cont.len);
1442 static bool cont_add(int facility, int level, const char *text, size_t len)
1444 if (cont.len && cont.flushed)
1447 if (cont.len + len > sizeof(cont.buf)) {
1448 /* the line gets too long, split it up in separate records */
1449 cont_flush(LOG_CONT);
1454 cont.facility = facility;
1456 cont.owner = current;
1457 cont.ts_nsec = local_clock();
1460 cont.flushed = false;
1463 memcpy(cont.buf + cont.len, text, len);
1466 if (cont.len > (sizeof(cont.buf) * 80) / 100)
1467 cont_flush(LOG_CONT);
1472 static size_t cont_print_text(char *text, size_t size)
1477 if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) {
1478 textlen += print_time(cont.ts_nsec, text);
1482 len = cont.len - cont.cons;
1486 memcpy(text + textlen, cont.buf + cont.cons, len);
1488 cont.cons = cont.len;
1492 if (cont.flags & LOG_NEWLINE)
1493 text[textlen++] = '\n';
1494 /* got everything, release buffer */
1500 asmlinkage int vprintk_emit(int facility, int level,
1501 const char *dict, size_t dictlen,
1502 const char *fmt, va_list args)
1504 static int recursion_bug;
1505 static char textbuf[LOG_LINE_MAX];
1506 char *text = textbuf;
1508 enum log_flags lflags = 0;
1509 unsigned long flags;
1511 int printed_len = 0;
1513 boot_delay_msec(level);
1516 /* This stops the holder of console_sem just where we want him */
1517 local_irq_save(flags);
1518 this_cpu = smp_processor_id();
1521 * Ouch, printk recursed into itself!
1523 if (unlikely(logbuf_cpu == this_cpu)) {
1525 * If a crash is occurring during printk() on this CPU,
1526 * then try to get the crash message out but make sure
1527 * we can't deadlock. Otherwise just return to avoid the
1528 * recursion and return - but flag the recursion so that
1529 * it can be printed at the next appropriate moment:
1531 if (!oops_in_progress && !lockdep_recursing(current)) {
1533 goto out_restore_irqs;
1539 raw_spin_lock(&logbuf_lock);
1540 logbuf_cpu = this_cpu;
1542 if (recursion_bug) {
1543 static const char recursion_msg[] =
1544 "BUG: recent printk recursion!";
1547 printed_len += strlen(recursion_msg);
1548 /* emit KERN_CRIT message */
1549 log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0,
1550 NULL, 0, recursion_msg, printed_len);
1554 * The printf needs to come first; we need the syslog
1555 * prefix which might be passed-in as a parameter.
1557 text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
1559 /* mark and strip a trailing newline */
1560 if (text_len && text[text_len-1] == '\n') {
1562 lflags |= LOG_NEWLINE;
1565 /* strip kernel syslog prefix and extract log level or control flags */
1566 if (facility == 0) {
1567 int kern_level = printk_get_level(text);
1570 const char *end_of_header = printk_skip_level(text);
1571 switch (kern_level) {
1574 level = kern_level - '0';
1575 case 'd': /* KERN_DEFAULT */
1576 lflags |= LOG_PREFIX;
1577 case 'c': /* KERN_CONT */
1580 text_len -= end_of_header - text;
1581 text = (char *)end_of_header;
1585 #ifdef CONFIG_EARLY_PRINTK_DIRECT
1590 level = default_message_loglevel;
1593 lflags |= LOG_PREFIX|LOG_NEWLINE;
1595 if (!(lflags & LOG_NEWLINE)) {
1597 * Flush the conflicting buffer. An earlier newline was missing,
1598 * or another task also prints continuation lines.
1600 if (cont.len && (lflags & LOG_PREFIX || cont.owner != current))
1601 cont_flush(LOG_NEWLINE);
1603 /* buffer line if possible, otherwise store it right away */
1604 if (!cont_add(facility, level, text, text_len))
1605 log_store(facility, level, lflags | LOG_CONT, 0,
1606 dict, dictlen, text, text_len);
1608 bool stored = false;
1611 * If an earlier newline was missing and it was the same task,
1612 * either merge it with the current buffer and flush, or if
1613 * there was a race with interrupts (prefix == true) then just
1614 * flush it out and store this line separately.
1616 if (cont.len && cont.owner == current) {
1617 if (!(lflags & LOG_PREFIX))
1618 stored = cont_add(facility, level, text, text_len);
1619 cont_flush(LOG_NEWLINE);
1623 log_store(facility, level, lflags, 0,
1624 dict, dictlen, text, text_len);
1626 printed_len += text_len;
1629 * Try to acquire and then immediately release the console semaphore.
1630 * The release will print out buffers and wake up /dev/kmsg and syslog()
1633 * The console_trylock_for_printk() function will release 'logbuf_lock'
1634 * regardless of whether it actually gets the console semaphore or not.
1636 if (console_trylock_for_printk(this_cpu))
1641 local_irq_restore(flags);
1645 EXPORT_SYMBOL(vprintk_emit);
1647 asmlinkage int vprintk(const char *fmt, va_list args)
1649 return vprintk_emit(0, -1, NULL, 0, fmt, args);
1651 EXPORT_SYMBOL(vprintk);
1653 asmlinkage int printk_emit(int facility, int level,
1654 const char *dict, size_t dictlen,
1655 const char *fmt, ...)
1660 va_start(args, fmt);
1661 r = vprintk_emit(facility, level, dict, dictlen, fmt, args);
1666 EXPORT_SYMBOL(printk_emit);
1669 * printk - print a kernel message
1670 * @fmt: format string
1672 * This is printk(). It can be called from any context. We want it to work.
1674 * We try to grab the console_lock. If we succeed, it's easy - we log the
1675 * output and call the console drivers. If we fail to get the semaphore, we
1676 * place the output into the log buffer and return. The current holder of
1677 * the console_sem will notice the new output in console_unlock(); and will
1678 * send it to the consoles before releasing the lock.
1680 * One effect of this deferred printing is that code which calls printk() and
1681 * then changes console_loglevel may break. This is because console_loglevel
1682 * is inspected when the actual printing occurs.
1687 * See the vsnprintf() documentation for format string extensions over C99.
1689 asmlinkage int printk(const char *fmt, ...)
1694 #ifdef CONFIG_KGDB_KDB
1695 if (unlikely(kdb_trap_printk)) {
1696 va_start(args, fmt);
1697 r = vkdb_printf(fmt, args);
1702 va_start(args, fmt);
1703 r = vprintk_emit(0, -1, NULL, 0, fmt, args);
1708 EXPORT_SYMBOL(printk);
1710 #else /* CONFIG_PRINTK */
1712 #define LOG_LINE_MAX 0
1713 #define PREFIX_MAX 0
1714 #define LOG_LINE_MAX 0
1715 static u64 syslog_seq;
1716 static u32 syslog_idx;
1717 static u64 console_seq;
1718 static u32 console_idx;
1719 static enum log_flags syslog_prev;
1720 static u64 log_first_seq;
1721 static u32 log_first_idx;
1722 static u64 log_next_seq;
1723 static enum log_flags console_prev;
1724 static struct cont {
1730 static struct log *log_from_idx(u32 idx) { return NULL; }
1731 static u32 log_next(u32 idx) { return 0; }
1732 static void call_console_drivers(int level, const char *text, size_t len) {}
1733 static size_t msg_print_text(const struct log *msg, enum log_flags prev,
1734 bool syslog, char *buf, size_t size) { return 0; }
1735 static size_t cont_print_text(char *text, size_t size) { return 0; }
1737 #endif /* CONFIG_PRINTK */
1739 #ifdef CONFIG_EARLY_PRINTK
1740 struct console *early_console;
1742 void early_vprintk(const char *fmt, va_list ap)
1744 if (early_console) {
1746 int n = vscnprintf(buf, sizeof(buf), fmt, ap);
1748 early_console->write(early_console, buf, n);
1752 asmlinkage void early_printk(const char *fmt, ...)
1757 early_vprintk(fmt, ap);
1762 static int __add_preferred_console(char *name, int idx, char *options,
1765 struct console_cmdline *c;
1769 * See if this tty is not yet registered, and
1770 * if we have a slot free.
1772 for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
1773 if (strcmp(console_cmdline[i].name, name) == 0 &&
1774 console_cmdline[i].index == idx) {
1776 selected_console = i;
1779 if (i == MAX_CMDLINECONSOLES)
1782 selected_console = i;
1783 c = &console_cmdline[i];
1784 strlcpy(c->name, name, sizeof(c->name));
1785 c->options = options;
1786 #ifdef CONFIG_A11Y_BRAILLE_CONSOLE
1787 c->brl_options = brl_options;
1793 * Set up a list of consoles. Called from init/main.c
1795 static int __init console_setup(char *str)
1797 char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */
1798 char *s, *options, *brl_options = NULL;
1801 #ifdef CONFIG_A11Y_BRAILLE_CONSOLE
1802 if (!memcmp(str, "brl,", 4)) {
1805 } else if (!memcmp(str, "brl=", 4)) {
1806 brl_options = str + 4;
1807 str = strchr(brl_options, ',');
1809 printk(KERN_ERR "need port name after brl=\n");
1817 * Decode str into name, index, options.
1819 if (str[0] >= '0' && str[0] <= '9') {
1820 strcpy(buf, "ttyS");
1821 strncpy(buf + 4, str, sizeof(buf) - 5);
1823 strncpy(buf, str, sizeof(buf) - 1);
1825 buf[sizeof(buf) - 1] = 0;
1826 if ((options = strchr(str, ',')) != NULL)
1829 if (!strcmp(str, "ttya"))
1830 strcpy(buf, "ttyS0");
1831 if (!strcmp(str, "ttyb"))
1832 strcpy(buf, "ttyS1");
1834 for (s = buf; *s; s++)
1835 if ((*s >= '0' && *s <= '9') || *s == ',')
1837 idx = simple_strtoul(s, NULL, 10);
1840 __add_preferred_console(buf, idx, options, brl_options);
1841 console_set_on_cmdline = 1;
1844 __setup("console=", console_setup);
1847 * add_preferred_console - add a device to the list of preferred consoles.
1848 * @name: device name
1849 * @idx: device index
1850 * @options: options for this console
1852 * The last preferred console added will be used for kernel messages
1853 * and stdin/out/err for init. Normally this is used by console_setup
1854 * above to handle user-supplied console arguments; however it can also
1855 * be used by arch-specific code either to override the user or more
1856 * commonly to provide a default console (ie from PROM variables) when
1857 * the user has not supplied one.
1859 int add_preferred_console(char *name, int idx, char *options)
1861 return __add_preferred_console(name, idx, options, NULL);
1864 int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options)
1866 struct console_cmdline *c;
1869 for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0]; i++)
1870 if (strcmp(console_cmdline[i].name, name) == 0 &&
1871 console_cmdline[i].index == idx) {
1872 c = &console_cmdline[i];
1873 strlcpy(c->name, name_new, sizeof(c->name));
1874 c->name[sizeof(c->name) - 1] = 0;
1875 c->options = options;
1883 bool console_suspend_enabled = 1;
1884 EXPORT_SYMBOL(console_suspend_enabled);
1886 static int __init console_suspend_disable(char *str)
1888 console_suspend_enabled = 0;
1891 __setup("no_console_suspend", console_suspend_disable);
1892 module_param_named(console_suspend, console_suspend_enabled,
1893 bool, S_IRUGO | S_IWUSR);
1894 MODULE_PARM_DESC(console_suspend, "suspend console during suspend"
1895 " and hibernate operations");
1898 * suspend_console - suspend the console subsystem
1900 * This disables printk() while we go into suspend states
1902 void suspend_console(void)
1904 if (!console_suspend_enabled)
1906 printk("Suspending console(s) (use no_console_suspend to debug)\n");
1908 console_suspended = 1;
1912 void resume_console(void)
1914 if (!console_suspend_enabled)
1917 console_suspended = 0;
1922 * console_cpu_notify - print deferred console messages after CPU hotplug
1923 * @self: notifier struct
1924 * @action: CPU hotplug event
1927 * If printk() is called from a CPU that is not online yet, the messages
1928 * will be spooled but will not show up on the console. This function is
1929 * called when a new CPU comes online (or fails to come up), and ensures
1930 * that any such output gets printed.
1932 static int __cpuinit console_cpu_notify(struct notifier_block *self,
1933 unsigned long action, void *hcpu)
1938 case CPU_DOWN_FAILED:
1939 case CPU_UP_CANCELED:
1947 * console_lock - lock the console system for exclusive use.
1949 * Acquires a lock which guarantees that the caller has
1950 * exclusive access to the console system and the console_drivers list.
1952 * Can sleep, returns nothing.
1954 void console_lock(void)
1959 if (console_suspended)
1962 console_may_schedule = 1;
1963 mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);
1965 EXPORT_SYMBOL(console_lock);
1968 * console_trylock - try to lock the console system for exclusive use.
1970 * Tried to acquire a lock which guarantees that the caller has
1971 * exclusive access to the console system and the console_drivers list.
1973 * returns 1 on success, and 0 on failure to acquire the lock.
1975 int console_trylock(void)
1977 if (down_trylock(&console_sem))
1979 if (console_suspended) {
1984 console_may_schedule = 0;
1985 mutex_acquire(&console_lock_dep_map, 0, 1, _RET_IP_);
1988 EXPORT_SYMBOL(console_trylock);
1990 int is_console_locked(void)
1992 return console_locked;
1995 static void console_cont_flush(char *text, size_t size)
1997 unsigned long flags;
2000 raw_spin_lock_irqsave(&logbuf_lock, flags);
2006 * We still queue earlier records, likely because the console was
2007 * busy. The earlier ones need to be printed before this one, we
2008 * did not flush any fragment so far, so just let it queue up.
2010 if (console_seq < log_next_seq && !cont.cons)
2013 len = cont_print_text(text, size);
2014 raw_spin_unlock(&logbuf_lock);
2015 stop_critical_timings();
2016 call_console_drivers(cont.level, text, len);
2017 start_critical_timings();
2018 local_irq_restore(flags);
2021 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2025 * console_unlock - unlock the console system
2027 * Releases the console_lock which the caller holds on the console system
2028 * and the console driver list.
2030 * While the console_lock was held, console output may have been buffered
2031 * by printk(). If this is the case, console_unlock(); emits
2032 * the output prior to releasing the lock.
2034 * If there is output waiting, we wake /dev/kmsg and syslog() users.
2036 * console_unlock(); may be called from any context.
2038 void console_unlock(void)
2040 static char text[LOG_LINE_MAX + PREFIX_MAX];
2041 static u64 seen_seq;
2042 unsigned long flags;
2043 bool wake_klogd = false;
2046 if (console_suspended) {
2051 console_may_schedule = 0;
2053 /* flush buffered message fragment immediately to console */
2054 console_cont_flush(text, sizeof(text));
2061 raw_spin_lock_irqsave(&logbuf_lock, flags);
2062 if (seen_seq != log_next_seq) {
2064 seen_seq = log_next_seq;
2067 if (console_seq < log_first_seq) {
2068 /* messages are gone, move to first one */
2069 console_seq = log_first_seq;
2070 console_idx = log_first_idx;
2074 if (console_seq == log_next_seq)
2077 msg = log_from_idx(console_idx);
2078 if (msg->flags & LOG_NOCONS) {
2080 * Skip record we have buffered and already printed
2081 * directly to the console when we received it.
2083 console_idx = log_next(console_idx);
2086 * We will get here again when we register a new
2087 * CON_PRINTBUFFER console. Clear the flag so we
2088 * will properly dump everything later.
2090 msg->flags &= ~LOG_NOCONS;
2091 console_prev = msg->flags;
2096 len = msg_print_text(msg, console_prev, false,
2097 text, sizeof(text));
2098 console_idx = log_next(console_idx);
2100 console_prev = msg->flags;
2101 raw_spin_unlock(&logbuf_lock);
2103 stop_critical_timings(); /* don't trace print latency */
2104 call_console_drivers(level, text, len);
2105 start_critical_timings();
2106 local_irq_restore(flags);
2109 mutex_release(&console_lock_dep_map, 1, _RET_IP_);
2111 /* Release the exclusive_console once it is used */
2112 if (unlikely(exclusive_console))
2113 exclusive_console = NULL;
2115 raw_spin_unlock(&logbuf_lock);
2120 * Someone could have filled up the buffer again, so re-check if there's
2121 * something to flush. In case we cannot trylock the console_sem again,
2122 * there's a new owner and the console_unlock() from them will do the
2123 * flush, no worries.
2125 raw_spin_lock(&logbuf_lock);
2126 retry = console_seq != log_next_seq;
2127 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2129 if (retry && console_trylock())
2135 EXPORT_SYMBOL(console_unlock);
2138 * console_conditional_schedule - yield the CPU if required
2140 * If the console code is currently allowed to sleep, and
2141 * if this CPU should yield the CPU to another task, do
2144 * Must be called within console_lock();.
2146 void __sched console_conditional_schedule(void)
2148 if (console_may_schedule)
2151 EXPORT_SYMBOL(console_conditional_schedule);
2153 void console_unblank(void)
2158 * console_unblank can no longer be called in interrupt context unless
2159 * oops_in_progress is set to 1..
2161 if (oops_in_progress) {
2162 if (down_trylock(&console_sem) != 0)
2168 console_may_schedule = 0;
2170 if ((c->flags & CON_ENABLED) && c->unblank)
2176 * Return the console tty driver structure and its associated index
2178 struct tty_driver *console_device(int *index)
2181 struct tty_driver *driver = NULL;
2184 for_each_console(c) {
2187 driver = c->device(c, index);
2196 * Prevent further output on the passed console device so that (for example)
2197 * serial drivers can disable console output before suspending a port, and can
2198 * re-enable output afterwards.
2200 void console_stop(struct console *console)
2203 console->flags &= ~CON_ENABLED;
2206 EXPORT_SYMBOL(console_stop);
2208 void console_start(struct console *console)
2211 console->flags |= CON_ENABLED;
2214 EXPORT_SYMBOL(console_start);
2216 static int __read_mostly keep_bootcon;
2218 static int __init keep_bootcon_setup(char *str)
2221 printk(KERN_INFO "debug: skip boot console de-registration.\n");
2226 early_param("keep_bootcon", keep_bootcon_setup);
2229 * The console driver calls this routine during kernel initialization
2230 * to register the console printing procedure with printk() and to
2231 * print any messages that were printed by the kernel before the
2232 * console driver was initialized.
2234 * This can happen pretty early during the boot process (because of
2235 * early_printk) - sometimes before setup_arch() completes - be careful
2236 * of what kernel features are used - they may not be initialised yet.
2238 * There are two types of consoles - bootconsoles (early_printk) and
2239 * "real" consoles (everything which is not a bootconsole) which are
2240 * handled differently.
2241 * - Any number of bootconsoles can be registered at any time.
2242 * - As soon as a "real" console is registered, all bootconsoles
2243 * will be unregistered automatically.
2244 * - Once a "real" console is registered, any attempt to register a
2245 * bootconsoles will be rejected
2247 void register_console(struct console *newcon)
2250 unsigned long flags;
2251 struct console *bcon = NULL;
2254 * before we register a new CON_BOOT console, make sure we don't
2255 * already have a valid console
2257 if (console_drivers && newcon->flags & CON_BOOT) {
2258 /* find the last or real console */
2259 for_each_console(bcon) {
2260 if (!(bcon->flags & CON_BOOT)) {
2261 printk(KERN_INFO "Too late to register bootconsole %s%d\n",
2262 newcon->name, newcon->index);
2268 if (console_drivers && console_drivers->flags & CON_BOOT)
2269 bcon = console_drivers;
2271 if (preferred_console < 0 || bcon || !console_drivers)
2272 preferred_console = selected_console;
2274 if (newcon->early_setup)
2275 newcon->early_setup();
2278 * See if we want to use this console driver. If we
2279 * didn't select a console we take the first one
2280 * that registers here.
2282 if (preferred_console < 0) {
2283 if (newcon->index < 0)
2285 if (newcon->setup == NULL ||
2286 newcon->setup(newcon, NULL) == 0) {
2287 newcon->flags |= CON_ENABLED;
2288 if (newcon->device) {
2289 newcon->flags |= CON_CONSDEV;
2290 preferred_console = 0;
2296 * See if this console matches one we selected on
2299 for (i = 0; i < MAX_CMDLINECONSOLES && console_cmdline[i].name[0];
2301 if (strcmp(console_cmdline[i].name, newcon->name) != 0)
2303 if (newcon->index >= 0 &&
2304 newcon->index != console_cmdline[i].index)
2306 if (newcon->index < 0)
2307 newcon->index = console_cmdline[i].index;
2308 #ifdef CONFIG_A11Y_BRAILLE_CONSOLE
2309 if (console_cmdline[i].brl_options) {
2310 newcon->flags |= CON_BRL;
2311 braille_register_console(newcon,
2312 console_cmdline[i].index,
2313 console_cmdline[i].options,
2314 console_cmdline[i].brl_options);
2318 if (newcon->setup &&
2319 newcon->setup(newcon, console_cmdline[i].options) != 0)
2321 newcon->flags |= CON_ENABLED;
2322 newcon->index = console_cmdline[i].index;
2323 if (i == selected_console) {
2324 newcon->flags |= CON_CONSDEV;
2325 preferred_console = selected_console;
2330 if (!(newcon->flags & CON_ENABLED))
2334 * If we have a bootconsole, and are switching to a real console,
2335 * don't print everything out again, since when the boot console, and
2336 * the real console are the same physical device, it's annoying to
2337 * see the beginning boot messages twice
2339 if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV))
2340 newcon->flags &= ~CON_PRINTBUFFER;
2343 * Put this console in the list - keep the
2344 * preferred driver at the head of the list.
2347 if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) {
2348 newcon->next = console_drivers;
2349 console_drivers = newcon;
2351 newcon->next->flags &= ~CON_CONSDEV;
2353 newcon->next = console_drivers->next;
2354 console_drivers->next = newcon;
2356 if (newcon->flags & CON_PRINTBUFFER) {
2358 * console_unlock(); will print out the buffered messages
2361 raw_spin_lock_irqsave(&logbuf_lock, flags);
2362 console_seq = syslog_seq;
2363 console_idx = syslog_idx;
2364 console_prev = syslog_prev;
2365 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2367 * We're about to replay the log buffer. Only do this to the
2368 * just-registered console to avoid excessive message spam to
2369 * the already-registered consoles.
2371 exclusive_console = newcon;
2374 console_sysfs_notify();
2377 * By unregistering the bootconsoles after we enable the real console
2378 * we get the "console xxx enabled" message on all the consoles -
2379 * boot consoles, real consoles, etc - this is to ensure that end
2380 * users know there might be something in the kernel's log buffer that
2381 * went to the bootconsole (that they do not see on the real console)
2384 ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) &&
2386 /* we need to iterate through twice, to make sure we print
2387 * everything out, before we unregister the console(s)
2389 printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n",
2390 newcon->name, newcon->index);
2391 for_each_console(bcon)
2392 if (bcon->flags & CON_BOOT)
2393 unregister_console(bcon);
2395 printk(KERN_INFO "%sconsole [%s%d] enabled\n",
2396 (newcon->flags & CON_BOOT) ? "boot" : "" ,
2397 newcon->name, newcon->index);
2400 EXPORT_SYMBOL(register_console);
2402 int unregister_console(struct console *console)
2404 struct console *a, *b;
2407 #ifdef CONFIG_A11Y_BRAILLE_CONSOLE
2408 if (console->flags & CON_BRL)
2409 return braille_unregister_console(console);
2413 if (console_drivers == console) {
2414 console_drivers=console->next;
2416 } else if (console_drivers) {
2417 for (a=console_drivers->next, b=console_drivers ;
2418 a; b=a, a=b->next) {
2428 * If this isn't the last console and it has CON_CONSDEV set, we
2429 * need to set it on the next preferred console.
2431 if (console_drivers != NULL && console->flags & CON_CONSDEV)
2432 console_drivers->flags |= CON_CONSDEV;
2435 console_sysfs_notify();
2438 EXPORT_SYMBOL(unregister_console);
2440 static int __init printk_late_init(void)
2442 struct console *con;
2444 for_each_console(con) {
2445 if (!keep_bootcon && con->flags & CON_BOOT) {
2446 printk(KERN_INFO "turn off boot console %s%d\n",
2447 con->name, con->index);
2448 unregister_console(con);
2451 hotcpu_notifier(console_cpu_notify, 0);
2454 late_initcall(printk_late_init);
2456 #if defined CONFIG_PRINTK
2458 * Delayed printk version, for scheduler-internal messages:
2460 #define PRINTK_BUF_SIZE 512
2462 #define PRINTK_PENDING_WAKEUP 0x01
2463 #define PRINTK_PENDING_SCHED 0x02
2465 static DEFINE_PER_CPU(int, printk_pending);
2466 static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf);
2468 static void wake_up_klogd_work_func(struct irq_work *irq_work)
2470 int pending = __this_cpu_xchg(printk_pending, 0);
2472 if (pending & PRINTK_PENDING_SCHED) {
2473 char *buf = __get_cpu_var(printk_sched_buf);
2474 printk(KERN_WARNING "[sched_delayed] %s", buf);
2477 if (pending & PRINTK_PENDING_WAKEUP)
2478 wake_up_interruptible(&log_wait);
2481 static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
2482 .func = wake_up_klogd_work_func,
2483 .flags = IRQ_WORK_LAZY,
2486 void wake_up_klogd(void)
2489 if (waitqueue_active(&log_wait)) {
2490 this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
2491 irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
2496 int printk_sched(const char *fmt, ...)
2498 unsigned long flags;
2503 local_irq_save(flags);
2504 buf = __get_cpu_var(printk_sched_buf);
2506 va_start(args, fmt);
2507 r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args);
2510 __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED);
2511 irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
2512 local_irq_restore(flags);
2518 * printk rate limiting, lifted from the networking subsystem.
2520 * This enforces a rate limit: not more than 10 kernel messages
2521 * every 5s to make a denial-of-service attack impossible.
2523 DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10);
2525 int __printk_ratelimit(const char *func)
2527 return ___ratelimit(&printk_ratelimit_state, func);
2529 EXPORT_SYMBOL(__printk_ratelimit);
2532 * printk_timed_ratelimit - caller-controlled printk ratelimiting
2533 * @caller_jiffies: pointer to caller's state
2534 * @interval_msecs: minimum interval between prints
2536 * printk_timed_ratelimit() returns true if more than @interval_msecs
2537 * milliseconds have elapsed since the last time printk_timed_ratelimit()
2540 bool printk_timed_ratelimit(unsigned long *caller_jiffies,
2541 unsigned int interval_msecs)
2543 if (*caller_jiffies == 0
2544 || !time_in_range(jiffies, *caller_jiffies,
2546 + msecs_to_jiffies(interval_msecs))) {
2547 *caller_jiffies = jiffies;
2552 EXPORT_SYMBOL(printk_timed_ratelimit);
2554 static DEFINE_SPINLOCK(dump_list_lock);
2555 static LIST_HEAD(dump_list);
2558 * kmsg_dump_register - register a kernel log dumper.
2559 * @dumper: pointer to the kmsg_dumper structure
2561 * Adds a kernel log dumper to the system. The dump callback in the
2562 * structure will be called when the kernel oopses or panics and must be
2563 * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise.
2565 int kmsg_dump_register(struct kmsg_dumper *dumper)
2567 unsigned long flags;
2570 /* The dump callback needs to be set */
2574 spin_lock_irqsave(&dump_list_lock, flags);
2575 /* Don't allow registering multiple times */
2576 if (!dumper->registered) {
2577 dumper->registered = 1;
2578 list_add_tail_rcu(&dumper->list, &dump_list);
2581 spin_unlock_irqrestore(&dump_list_lock, flags);
2585 EXPORT_SYMBOL_GPL(kmsg_dump_register);
2588 * kmsg_dump_unregister - unregister a kmsg dumper.
2589 * @dumper: pointer to the kmsg_dumper structure
2591 * Removes a dump device from the system. Returns zero on success and
2592 * %-EINVAL otherwise.
2594 int kmsg_dump_unregister(struct kmsg_dumper *dumper)
2596 unsigned long flags;
2599 spin_lock_irqsave(&dump_list_lock, flags);
2600 if (dumper->registered) {
2601 dumper->registered = 0;
2602 list_del_rcu(&dumper->list);
2605 spin_unlock_irqrestore(&dump_list_lock, flags);
2610 EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
2612 static bool always_kmsg_dump;
2613 module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
2616 * kmsg_dump - dump kernel log to kernel message dumpers.
2617 * @reason: the reason (oops, panic etc) for dumping
2619 * Call each of the registered dumper's dump() callback, which can
2620 * retrieve the kmsg records with kmsg_dump_get_line() or
2621 * kmsg_dump_get_buffer().
2623 void kmsg_dump(enum kmsg_dump_reason reason)
2625 struct kmsg_dumper *dumper;
2626 unsigned long flags;
2628 if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
2632 list_for_each_entry_rcu(dumper, &dump_list, list) {
2633 if (dumper->max_reason && reason > dumper->max_reason)
2636 /* initialize iterator with data about the stored records */
2637 dumper->active = true;
2639 raw_spin_lock_irqsave(&logbuf_lock, flags);
2640 dumper->cur_seq = clear_seq;
2641 dumper->cur_idx = clear_idx;
2642 dumper->next_seq = log_next_seq;
2643 dumper->next_idx = log_next_idx;
2644 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2646 /* invoke dumper which will iterate over records */
2647 dumper->dump(dumper, reason);
2649 /* reset iterator */
2650 dumper->active = false;
2656 * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
2657 * @dumper: registered kmsg dumper
2658 * @syslog: include the "<4>" prefixes
2659 * @line: buffer to copy the line to
2660 * @size: maximum size of the buffer
2661 * @len: length of line placed into buffer
2663 * Start at the beginning of the kmsg buffer, with the oldest kmsg
2664 * record, and copy one record into the provided buffer.
2666 * Consecutive calls will return the next available record moving
2667 * towards the end of the buffer with the youngest messages.
2669 * A return value of FALSE indicates that there are no more records to
2672 * The function is similar to kmsg_dump_get_line(), but grabs no locks.
2674 bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
2675 char *line, size_t size, size_t *len)
2681 if (!dumper->active)
2684 if (dumper->cur_seq < log_first_seq) {
2685 /* messages are gone, move to first available one */
2686 dumper->cur_seq = log_first_seq;
2687 dumper->cur_idx = log_first_idx;
2691 if (dumper->cur_seq >= log_next_seq)
2694 msg = log_from_idx(dumper->cur_idx);
2695 l = msg_print_text(msg, 0, syslog, line, size);
2697 dumper->cur_idx = log_next(dumper->cur_idx);
2707 * kmsg_dump_get_line - retrieve one kmsg log line
2708 * @dumper: registered kmsg dumper
2709 * @syslog: include the "<4>" prefixes
2710 * @line: buffer to copy the line to
2711 * @size: maximum size of the buffer
2712 * @len: length of line placed into buffer
2714 * Start at the beginning of the kmsg buffer, with the oldest kmsg
2715 * record, and copy one record into the provided buffer.
2717 * Consecutive calls will return the next available record moving
2718 * towards the end of the buffer with the youngest messages.
2720 * A return value of FALSE indicates that there are no more records to
2723 bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
2724 char *line, size_t size, size_t *len)
2726 unsigned long flags;
2729 raw_spin_lock_irqsave(&logbuf_lock, flags);
2730 ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
2731 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2735 EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
2738 * kmsg_dump_get_buffer - copy kmsg log lines
2739 * @dumper: registered kmsg dumper
2740 * @syslog: include the "<4>" prefixes
2741 * @buf: buffer to copy the line to
2742 * @size: maximum size of the buffer
2743 * @len: length of line placed into buffer
2745 * Start at the end of the kmsg buffer and fill the provided buffer
2746 * with as many of the the *youngest* kmsg records that fit into it.
2747 * If the buffer is large enough, all available kmsg records will be
2748 * copied with a single call.
2750 * Consecutive calls will fill the buffer with the next block of
2751 * available older records, not including the earlier retrieved ones.
2753 * A return value of FALSE indicates that there are no more records to
2756 bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
2757 char *buf, size_t size, size_t *len)
2759 unsigned long flags;
2764 enum log_flags prev;
2768 if (!dumper->active)
2771 raw_spin_lock_irqsave(&logbuf_lock, flags);
2772 if (dumper->cur_seq < log_first_seq) {
2773 /* messages are gone, move to first available one */
2774 dumper->cur_seq = log_first_seq;
2775 dumper->cur_idx = log_first_idx;
2779 if (dumper->cur_seq >= dumper->next_seq) {
2780 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2784 /* calculate length of entire buffer */
2785 seq = dumper->cur_seq;
2786 idx = dumper->cur_idx;
2788 while (seq < dumper->next_seq) {
2789 struct log *msg = log_from_idx(idx);
2791 l += msg_print_text(msg, prev, true, NULL, 0);
2792 idx = log_next(idx);
2797 /* move first record forward until length fits into the buffer */
2798 seq = dumper->cur_seq;
2799 idx = dumper->cur_idx;
2801 while (l > size && seq < dumper->next_seq) {
2802 struct log *msg = log_from_idx(idx);
2804 l -= msg_print_text(msg, prev, true, NULL, 0);
2805 idx = log_next(idx);
2810 /* last message in next interation */
2816 while (seq < dumper->next_seq) {
2817 struct log *msg = log_from_idx(idx);
2819 l += msg_print_text(msg, prev, syslog, buf + l, size - l);
2820 idx = log_next(idx);
2825 dumper->next_seq = next_seq;
2826 dumper->next_idx = next_idx;
2828 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2834 EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
2837 * kmsg_dump_rewind_nolock - reset the interator (unlocked version)
2838 * @dumper: registered kmsg dumper
2840 * Reset the dumper's iterator so that kmsg_dump_get_line() and
2841 * kmsg_dump_get_buffer() can be called again and used multiple
2842 * times within the same dumper.dump() callback.
2844 * The function is similar to kmsg_dump_rewind(), but grabs no locks.
2846 void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
2848 dumper->cur_seq = clear_seq;
2849 dumper->cur_idx = clear_idx;
2850 dumper->next_seq = log_next_seq;
2851 dumper->next_idx = log_next_idx;
2855 * kmsg_dump_rewind - reset the interator
2856 * @dumper: registered kmsg dumper
2858 * Reset the dumper's iterator so that kmsg_dump_get_line() and
2859 * kmsg_dump_get_buffer() can be called again and used multiple
2860 * times within the same dumper.dump() callback.
2862 void kmsg_dump_rewind(struct kmsg_dumper *dumper)
2864 unsigned long flags;
2866 raw_spin_lock_irqsave(&logbuf_lock, flags);
2867 kmsg_dump_rewind_nolock(dumper);
2868 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
2870 EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
2872 static char dump_stack_arch_desc_str[128];
2875 * dump_stack_set_arch_desc - set arch-specific str to show with task dumps
2876 * @fmt: printf-style format string
2877 * @...: arguments for the format string
2879 * The configured string will be printed right after utsname during task
2880 * dumps. Usually used to add arch-specific system identifiers. If an
2881 * arch wants to make use of such an ID string, it should initialize this
2882 * as soon as possible during boot.
2884 void __init dump_stack_set_arch_desc(const char *fmt, ...)
2888 va_start(args, fmt);
2889 vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
2895 * dump_stack_print_info - print generic debug info for dump_stack()
2896 * @log_lvl: log level
2898 * Arch-specific dump_stack() implementations can use this function to
2899 * print out the same debug information as the generic dump_stack().
2901 void dump_stack_print_info(const char *log_lvl)
2903 printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n",
2904 log_lvl, raw_smp_processor_id(), current->pid, current->comm,
2905 print_tainted(), init_utsname()->release,
2906 (int)strcspn(init_utsname()->version, " "),
2907 init_utsname()->version);
2909 if (dump_stack_arch_desc_str[0] != '\0')
2910 printk("%sHardware name: %s\n",
2911 log_lvl, dump_stack_arch_desc_str);
2913 print_worker_info(log_lvl, current);
2917 * show_regs_print_info - print generic debug info for show_regs()
2918 * @log_lvl: log level
2920 * show_regs() implementations can use this function to print out generic
2921 * debug information.
2923 void show_regs_print_info(const char *log_lvl)
2925 dump_stack_print_info(log_lvl);
2927 printk("%stask: %p ti: %p task.ti: %p\n",
2928 log_lvl, current, current_thread_info(),
2929 task_thread_info(current));