1 files changed, 324 insertions, 145 deletions

diff --git a/kernel/printk.c b/kernel/printk.c
index a2276b916769..177fa49357a5 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -193,12 +193,21 @@ static int console_may_schedule;
  * separated by ',', and find the message after the ';' character.
  */
 
+enum log_flags {
+        LOG_NOCONS      = 1,    /* already flushed, do not print to console */
+        LOG_NEWLINE     = 2,    /* text ended with a newline */
+        LOG_PREFIX      = 4,    /* text started with a prefix */
+        LOG_CONT        = 8,    /* text is a fragment of a continuation line */
+};
+
 struct log {
         u64 ts_nsec;            /* timestamp in nanoseconds */
         u16 len;                /* length of entire record */
         u16 text_len;           /* length of text buffer */
         u16 dict_len;           /* length of dictionary buffer */
-        u16 level;              /* syslog level + facility */
+        u8 facility;            /* syslog facility */
+        u8 flags:5;             /* internal record flags */
+        u8 level:3;             /* syslog level */
 };
 
 /*
@@ -210,6 +219,8 @@ static DEFINE_RAW_SPINLOCK(logbuf_lock);
 /* the next printk record to read by syslog(READ) or /proc/kmsg */
 static u64 syslog_seq;
 static u32 syslog_idx;
+static enum log_flags syslog_prev;
+static size_t syslog_partial;
 
 /* index and sequence number of the first record stored in the buffer */
 static u64 log_first_seq;
@@ -286,6 +297,7 @@ static u32 log_next(u32 idx)
 
 /* insert record into the buffer, discard old ones, update heads */
 static void log_store(int facility, int level,
+                      enum log_flags flags, u64 ts_nsec,
                       const char *dict, u16 dict_len,
                       const char *text, u16 text_len)
 {
@@ -329,8 +341,13 @@ static void log_store(int facility, int level,
         msg->text_len = text_len;
         memcpy(log_dict(msg), dict, dict_len);
         msg->dict_len = dict_len;
-        msg->level = (facility << 3) | (level & 7);
-        msg->ts_nsec = local_clock();
+        msg->facility = facility;
+        msg->level = level & 7;
+        msg->flags = flags & 0x1f;
+        if (ts_nsec > 0)
+                msg->ts_nsec = ts_nsec;
+        else
+                msg->ts_nsec = local_clock();
         memset(log_dict(msg) + dict_len, 0, pad_len);
         msg->len = sizeof(struct log) + text_len + dict_len + pad_len;
 
@@ -417,20 +434,20 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
         ret = mutex_lock_interruptible(&user->lock);
         if (ret)
                 return ret;
-        raw_spin_lock(&logbuf_lock);
+        raw_spin_lock_irq(&logbuf_lock);
         while (user->seq == log_next_seq) {
                 if (file->f_flags & O_NONBLOCK) {
                         ret = -EAGAIN;
-                        raw_spin_unlock(&logbuf_lock);
+                        raw_spin_unlock_irq(&logbuf_lock);
                         goto out;
                 }
 
-                raw_spin_unlock(&logbuf_lock);
+                raw_spin_unlock_irq(&logbuf_lock);
                 ret = wait_event_interruptible(log_wait,
                                                user->seq != log_next_seq);
                 if (ret)
                         goto out;
-                raw_spin_lock(&logbuf_lock);
+                raw_spin_lock_irq(&logbuf_lock);
         }
 
         if (user->seq < log_first_seq) {
@@ -438,7 +455,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
                 user->idx = log_first_idx;
                 user->seq = log_first_seq;
                 ret = -EPIPE;
-                raw_spin_unlock(&logbuf_lock);
+                raw_spin_unlock_irq(&logbuf_lock);
                 goto out;
         }
 
@@ -446,13 +463,13 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
         ts_usec = msg->ts_nsec;
         do_div(ts_usec, 1000);
         len = sprintf(user->buf, "%u,%llu,%llu;",
-                      msg->level, user->seq, ts_usec);
+                      (msg->facility << 3) | msg->level, user->seq, ts_usec);
 
         /* escape non-printable characters */
         for (i = 0; i < msg->text_len; i++) {
                 unsigned char c = log_text(msg)[i];
 
-                if (c < ' ' || c >= 128)
+                if (c < ' ' || c >= 127 || c == '\\')
                         len += sprintf(user->buf + len, "\\x%02x", c);
                 else
                         user->buf[len++] = c;
@@ -476,7 +493,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
                                 continue;
                         }
 
-                        if (c < ' ' || c >= 128) {
+                        if (c < ' ' || c >= 127 || c == '\\') {
                                 len += sprintf(user->buf + len, "\\x%02x", c);
                                 continue;
                         }
@@ -488,7 +505,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
 
         user->idx = log_next(user->idx);
         user->seq++;
-        raw_spin_unlock(&logbuf_lock);
+        raw_spin_unlock_irq(&logbuf_lock);
 
         if (len > count) {
                 ret = -EINVAL;
@@ -515,7 +532,7 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
         if (offset)
                 return -ESPIPE;
 
-        raw_spin_lock(&logbuf_lock);
+        raw_spin_lock_irq(&logbuf_lock);
         switch (whence) {
         case SEEK_SET:
                 /* the first record */
@@ -539,7 +556,7 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
         default:
                 ret = -EINVAL;
         }
-        raw_spin_unlock(&logbuf_lock);
+        raw_spin_unlock_irq(&logbuf_lock);
         return ret;
 }
 
@@ -553,14 +570,14 @@ static unsigned int devkmsg_poll(struct file *file, poll_table *wait)
 
         poll_wait(file, &log_wait, wait);
 
-        raw_spin_lock(&logbuf_lock);
+        raw_spin_lock_irq(&logbuf_lock);
         if (user->seq < log_next_seq) {
                 /* return error when data has vanished underneath us */
                 if (user->seq < log_first_seq)
                         ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI;
                 ret = POLLIN|POLLRDNORM;
         }
-        raw_spin_unlock(&logbuf_lock);
+        raw_spin_unlock_irq(&logbuf_lock);
 
         return ret;
 }
@@ -584,10 +601,10 @@ static int devkmsg_open(struct inode *inode, struct file *file)
 
         mutex_init(&user->lock);
 
-        raw_spin_lock(&logbuf_lock);
+        raw_spin_lock_irq(&logbuf_lock);
         user->idx = log_first_idx;
         user->seq = log_first_seq;
-        raw_spin_unlock(&logbuf_lock);
+        raw_spin_unlock_irq(&logbuf_lock);
 
         file->private_data = user;
         return 0;
@@ -787,44 +804,64 @@ static bool printk_time;
 #endif
 module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
 
+static size_t print_time(u64 ts, char *buf)
+{
+        unsigned long rem_nsec;
+
+        if (!printk_time)
+                return 0;
+
+        if (!buf)
+                return 15;
+
+        rem_nsec = do_div(ts, 1000000000);
+        return sprintf(buf, "[%5lu.%06lu] ",
+                       (unsigned long)ts, rem_nsec / 1000);
+}
+
 static size_t print_prefix(const struct log *msg, bool syslog, char *buf)
 {
         size_t len = 0;
+        unsigned int prefix = (msg->facility << 3) | msg->level;
 
         if (syslog) {
                 if (buf) {
-                        len += sprintf(buf, "<%u>", msg->level);
+                        len += sprintf(buf, "<%u>", prefix);
                 } else {
                         len += 3;
-                        if (msg->level > 9)
-                                len++;
-                        if (msg->level > 99)
+                        if (prefix > 999)
+                                len += 3;
+                        else if (prefix > 99)
+                                len += 2;
+                        else if (prefix > 9)
                                 len++;
                 }
         }
 
-        if (printk_time) {
-                if (buf) {
-                        unsigned long long ts = msg->ts_nsec;
-                        unsigned long rem_nsec = do_div(ts, 1000000000);
-
-                        len += sprintf(buf + len, "[%5lu.%06lu] ",
-                                         (unsigned long) ts, rem_nsec / 1000);
-                } else {
-                        len += 15;
-                }
-        }
-
+        len += print_time(msg->ts_nsec, buf ? buf + len : NULL);
         return len;
 }
 
-static size_t msg_print_text(const struct log *msg, bool syslog,
-                             char *buf, size_t size)
+static size_t msg_print_text(const struct log *msg, enum log_flags prev,
+                             bool syslog, char *buf, size_t size)
 {
         const char *text = log_text(msg);
         size_t text_size = msg->text_len;
+        bool prefix = true;
+        bool newline = true;
         size_t len = 0;
 
+        if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))
+                prefix = false;
+
+        if (msg->flags & LOG_CONT) {
+                if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE))
+                        prefix = false;
+
+                if (!(msg->flags & LOG_NEWLINE))
+                        newline = false;
+        }
+
         do {
                 const char *next = memchr(text, '\n', text_size);
                 size_t text_len;
@@ -842,16 +879,22 @@ static size_t msg_print_text(const struct log *msg, bool syslog,
                             text_len + 1>= size - len)
                                 break;
 
-                        len += print_prefix(msg, syslog, buf + len);
+                        if (prefix)
+                                len += print_prefix(msg, syslog, buf + len);
                         memcpy(buf + len, text, text_len);
                         len += text_len;
-                        buf[len++] = '\n';
+                        if (next || newline)
+                                buf[len++] = '\n';
                 } else {
                         /* SYSLOG_ACTION_* buffer size only calculation */
-                        len += print_prefix(msg, syslog, NULL);
-                        len += text_len + 1;
+                        if (prefix)
+                                len += print_prefix(msg, syslog, NULL);
+                        len += text_len;
+                        if (next || newline)
+                                len++;
                 }
 
+                prefix = true;
                 text = next;
         } while (text);
 
@@ -862,28 +905,60 @@ static int syslog_print(char __user *buf, int size)
 {
         char *text;
         struct log *msg;
-        int len;
+        int len = 0;
 
         text = kmalloc(LOG_LINE_MAX, GFP_KERNEL);
         if (!text)
                 return -ENOMEM;
 
-        raw_spin_lock_irq(&logbuf_lock);
-        if (syslog_seq < log_first_seq) {
-                /* messages are gone, move to first one */
-                syslog_seq = log_first_seq;
-                syslog_idx = log_first_idx;
-        }
-        msg = log_from_idx(syslog_idx);
-        len = msg_print_text(msg, true, text, LOG_LINE_MAX);
-        syslog_idx = log_next(syslog_idx);
-        syslog_seq++;
-        raw_spin_unlock_irq(&logbuf_lock);
+        while (size > 0) {
+                size_t n;
+                size_t skip;
 
-        if (len > size)
-                len = -EINVAL;
-        else if (len > 0 && copy_to_user(buf, text, len))
-                len = -EFAULT;
+                raw_spin_lock_irq(&logbuf_lock);
+                if (syslog_seq < log_first_seq) {
+                        /* messages are gone, move to first one */
+                        syslog_seq = log_first_seq;
+                        syslog_idx = log_first_idx;
+                        syslog_prev = 0;
+                        syslog_partial = 0;
+                }
+                if (syslog_seq == log_next_seq) {
+                        raw_spin_unlock_irq(&logbuf_lock);
+                        break;
+                }
+
+                skip = syslog_partial;
+                msg = log_from_idx(syslog_idx);
+                n = msg_print_text(msg, syslog_prev, true, text, LOG_LINE_MAX);
+                if (n - syslog_partial <= size) {
+                        /* message fits into buffer, move forward */
+                        syslog_idx = log_next(syslog_idx);
+                        syslog_seq++;
+                        syslog_prev = msg->flags;
+                        n -= syslog_partial;
+                        syslog_partial = 0;
+                } else if (!len){
+                        /* partial read(), remember position */
+                        n = size;
+                        syslog_partial += n;
+                } else
+                        n = 0;
+                raw_spin_unlock_irq(&logbuf_lock);
+
+                if (!n)
+                        break;
+
+                if (copy_to_user(buf, text + skip, n)) {
+                        if (!len)
+                                len = -EFAULT;
+                        break;
+                }
+
+                len += n;
+                size -= n;
+                buf += n;
+        }
 
         kfree(text);
         return len;
@@ -903,6 +978,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
                 u64 next_seq;
                 u64 seq;
                 u32 idx;
+                enum log_flags prev;
 
                 if (clear_seq < log_first_seq) {
                         /* messages are gone, move to first available one */
@@ -916,10 +992,11 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
                  */
                 seq = clear_seq;
                 idx = clear_idx;
+                prev = 0;
                 while (seq < log_next_seq) {
                         struct log *msg = log_from_idx(idx);
 
-                        len += msg_print_text(msg, true, NULL, 0);
+                        len += msg_print_text(msg, prev, true, NULL, 0);
                         idx = log_next(idx);
                         seq++;
                 }
@@ -927,10 +1004,11 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
                 /* move first record forward until length fits into the buffer */
                 seq = clear_seq;
                 idx = clear_idx;
+                prev = 0;
                 while (len > size && seq < log_next_seq) {
                         struct log *msg = log_from_idx(idx);
 
-                        len -= msg_print_text(msg, true, NULL, 0);
+                        len -= msg_print_text(msg, prev, true, NULL, 0);
                         idx = log_next(idx);
                         seq++;
                 }
@@ -939,17 +1017,19 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
                 next_seq = log_next_seq;
 
                 len = 0;
+                prev = 0;
                 while (len >= 0 && seq < next_seq) {
                         struct log *msg = log_from_idx(idx);
                         int textlen;
 
-                        textlen = msg_print_text(msg, true, text, LOG_LINE_MAX);
+                        textlen = msg_print_text(msg, prev, true, text, LOG_LINE_MAX);
                         if (textlen < 0) {
                                 len = textlen;
                                 break;
                         }
                         idx = log_next(idx);
                         seq++;
+                        prev = msg->flags;
 
                         raw_spin_unlock_irq(&logbuf_lock);
                         if (copy_to_user(buf + len, text, textlen))
@@ -962,6 +1042,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
                                 /* messages are gone, move to next one */
                                 seq = log_first_seq;
                                 idx = log_first_idx;
+                                prev = 0;
                         }
                 }
         }
@@ -980,7 +1061,6 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
 {
         bool clear = false;
         static int saved_console_loglevel = -1;
-        static DEFINE_MUTEX(syslog_mutex);
         int error;
 
         error = check_syslog_permissions(type, from_file);
@@ -1007,17 +1087,11 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
                         error = -EFAULT;
                         goto out;
                 }
-                error = mutex_lock_interruptible(&syslog_mutex);
-                if (error)
-                        goto out;
                 error = wait_event_interruptible(log_wait,
                                                  syslog_seq != log_next_seq);
-                if (error) {
-                        mutex_unlock(&syslog_mutex);
+                if (error)
                         goto out;
-                }
                 error = syslog_print(buf, len);
-                mutex_unlock(&syslog_mutex);
                 break;
         /* Read/clear last kernel messages */
         case SYSLOG_ACTION_READ_CLEAR:
@@ -1040,6 +1114,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
         /* Clear ring buffer */
         case SYSLOG_ACTION_CLEAR:
                 syslog_print_all(NULL, 0, true);
+                break;
         /* Disable logging to console */
         case SYSLOG_ACTION_CONSOLE_OFF:
                 if (saved_console_loglevel == -1)
@@ -1072,6 +1147,8 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
                         /* messages are gone, move to first one */
                         syslog_seq = log_first_seq;
                         syslog_idx = log_first_idx;
+                        syslog_prev = 0;
+                        syslog_partial = 0;
                 }
                 if (from_file) {
                         /*
@@ -1081,19 +1158,20 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
                          */
                         error = log_next_idx - syslog_idx;
                 } else {
-                        u64 seq;
-                        u32 idx;
+                        u64 seq = syslog_seq;
+                        u32 idx = syslog_idx;
+                        enum log_flags prev = syslog_prev;
 
                         error = 0;
-                        seq = syslog_seq;
-                        idx = syslog_idx;
                         while (seq < log_next_seq) {
                                 struct log *msg = log_from_idx(idx);
 
-                                error += msg_print_text(msg, true, NULL, 0);
+                                error += msg_print_text(msg, prev, true, NULL, 0);
                                 idx = log_next(idx);
                                 seq++;
+                                prev = msg->flags;
                         }
+                        error -= syslog_partial;
                 }
                 raw_spin_unlock_irq(&logbuf_lock);
                 break;
@@ -1272,22 +1350,98 @@ static inline void printk_delay(void)
         }
 }
 
+/*
+ * Continuation lines are buffered, and not committed to the record buffer
+ * until the line is complete, or a race forces it. The line fragments
+ * though, are printed immediately to the consoles to ensure everything has
+ * reached the console in case of a kernel crash.
+ */
+static struct cont {
+        char buf[LOG_LINE_MAX];
+        size_t len;                     /* length == 0 means unused buffer */
+        size_t cons;                    /* bytes written to console */
+        struct task_struct *owner;      /* task of first print*/
+        u64 ts_nsec;                    /* time of first print */
+        u8 level;                       /* log level of first message */
+        u8 facility;                    /* log level of first message */
+        bool flushed:1;                 /* buffer sealed and committed */
+} cont;
+
+static void cont_flush(void)
+{
+        if (cont.flushed)
+                return;
+        if (cont.len == 0)
+                return;
+
+        log_store(cont.facility, cont.level, LOG_NOCONS, cont.ts_nsec,
+                  NULL, 0, cont.buf, cont.len);
+
+        cont.flushed = true;
+}
+
+static bool cont_add(int facility, int level, const char *text, size_t len)
+{
+        if (cont.len && cont.flushed)
+                return false;
+
+        if (cont.len + len > sizeof(cont.buf)) {
+                cont_flush();
+                return false;
+        }
+
+        if (!cont.len) {
+                cont.facility = facility;
+                cont.level = level;
+                cont.owner = current;
+                cont.ts_nsec = local_clock();
+                cont.cons = 0;
+                cont.flushed = false;
+        }
+
+        memcpy(cont.buf + cont.len, text, len);
+        cont.len += len;
+        return true;
+}
+
+static size_t cont_print_text(char *text, size_t size)
+{
+        size_t textlen = 0;
+        size_t len;
+
+        if (cont.cons == 0) {
+                textlen += print_time(cont.ts_nsec, text);
+                size -= textlen;
+        }
+
+        len = cont.len - cont.cons;
+        if (len > 0) {
+                if (len+1 > size)
+                        len = size-1;
+                memcpy(text + textlen, cont.buf + cont.cons, len);
+                textlen += len;
+                cont.cons = cont.len;
+        }
+
+        if (cont.flushed) {
+                text[textlen++] = '\n';
+                /* got everything, release buffer */
+                cont.len = 0;
+        }
+        return textlen;
+}
+
 asmlinkage int vprintk_emit(int facility, int level,
                             const char *dict, size_t dictlen,
                             const char *fmt, va_list args)
 {
         static int recursion_bug;
-        static char cont_buf[LOG_LINE_MAX];
-        static size_t cont_len;
-        static int cont_level;
-        static struct task_struct *cont_task;
         static char textbuf[LOG_LINE_MAX];
         char *text = textbuf;
         size_t text_len;
+        enum log_flags lflags = 0;
         unsigned long flags;
         int this_cpu;
-        bool newline = false;
-        bool prefix = false;
         int printed_len = 0;
 
         boot_delay_msec();
@@ -1326,7 +1480,8 @@ asmlinkage int vprintk_emit(int facility, int level,
                 recursion_bug = 0;
                 printed_len += strlen(recursion_msg);
                 /* emit KERN_CRIT message */
-                log_store(0, 2, NULL, 0, recursion_msg, printed_len);
+                log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0,
+                          NULL, 0, recursion_msg, printed_len);
         }
 
         /*
@@ -1338,7 +1493,7 @@ asmlinkage int vprintk_emit(int facility, int level,
         /* mark and strip a trailing newline */
         if (text_len && text[text_len-1] == '\n') {
                 text_len--;
-                newline = true;
+                lflags |= LOG_NEWLINE;
         }
 
         /* strip syslog prefix and extract log level or control flags */
@@ -1348,7 +1503,7 @@ asmlinkage int vprintk_emit(int facility, int level,
                         if (level == -1)
                                 level = text[1] - '0';
                 case 'd':       /* KERN_DEFAULT */
-                        prefix = true;
+                        lflags |= LOG_PREFIX;
                 case 'c':       /* KERN_CONT */
                         text += 3;
                         text_len -= 3;
@@ -1358,61 +1513,41 @@ asmlinkage int vprintk_emit(int facility, int level,
         if (level == -1)
                 level = default_message_loglevel;
 
-        if (dict) {
-                prefix = true;
-                newline = true;
-        }
+        if (dict)
+                lflags |= LOG_PREFIX|LOG_NEWLINE;
 
-        if (!newline) {
-                if (cont_len && (prefix || cont_task != current)) {
-                        /*
-                         * Flush earlier buffer, which is either from a
-                         * different thread, or when we got a new prefix.
-                         */
-                        log_store(facility, cont_level, NULL, 0, cont_buf, cont_len);
-                        cont_len = 0;
-                }
-
-                if (!cont_len) {
-                        cont_level = level;
-                        cont_task = current;
-                }
+        if (!(lflags & LOG_NEWLINE)) {
+                /*
+                 * Flush the conflicting buffer. An earlier newline was missing,
+                 * or another task also prints continuation lines.
+                 */
+                if (cont.len && (lflags & LOG_PREFIX || cont.owner != current))
+                        cont_flush();
 
-                /* buffer or append to earlier buffer from the same thread */
-                if (cont_len + text_len > sizeof(cont_buf))
-                        text_len = sizeof(cont_buf) - cont_len;
-                memcpy(cont_buf + cont_len, text, text_len);
-                cont_len += text_len;
+                /* buffer line if possible, otherwise store it right away */
+                if (!cont_add(facility, level, text, text_len))
+                        log_store(facility, level, lflags | LOG_CONT, 0,
+                                  dict, dictlen, text, text_len);
         } else {
-                if (cont_len && cont_task == current) {
-                        if (prefix) {
-                                /*
-                                 * New prefix from the same thread; flush. We
-                                 * either got no earlier newline, or we race
-                                 * with an interrupt.
-                                 */
-                                log_store(facility, cont_level,
-                                          NULL, 0, cont_buf, cont_len);
-                                cont_len = 0;
-                        }
+                bool stored = false;
 
-                        /* append to the earlier buffer and flush */
-                        if (cont_len + text_len > sizeof(cont_buf))
-                                text_len = sizeof(cont_buf) - cont_len;
-                        memcpy(cont_buf + cont_len, text, text_len);
-                        cont_len += text_len;
-                        log_store(facility, cont_level,
-                                  NULL, 0, cont_buf, cont_len);
-                        cont_len = 0;
-                        cont_task = NULL;
-                        printed_len = cont_len;
-                } else {
-                        /* ordinary single and terminated line */
-                        log_store(facility, level,
-                                  dict, dictlen, text, text_len);
-                        printed_len = text_len;
+                /*
+                 * If an earlier newline was missing and it was the same task,
+                 * either merge it with the current buffer and flush, or if
+                 * there was a race with interrupts (prefix == true) then just
+                 * flush it out and store this line separately.
+                 */
+                if (cont.len && cont.owner == current) {
+                        if (!(lflags & LOG_PREFIX))
+                                stored = cont_add(facility, level, text, text_len);
+                        cont_flush();
                 }
+
+                if (!stored)
+                        log_store(facility, level, lflags, 0,
+                                  dict, dictlen, text, text_len);
         }
+        printed_len += text_len;
 
         /*
          * Try to acquire and then immediately release the console semaphore.
@@ -1499,11 +1634,18 @@ EXPORT_SYMBOL(printk);
 #else
 
 #define LOG_LINE_MAX 0
+static struct cont {
+        size_t len;
+        size_t cons;
+        u8 level;
+        bool flushed:1;
+} cont;
 static struct log *log_from_idx(u32 idx) { return NULL; }
 static u32 log_next(u32 idx) { return 0; }
 static void call_console_drivers(int level, const char *text, size_t len) {}
-static size_t msg_print_text(const struct log *msg, bool syslog,
-                             char *buf, size_t size) { return 0; }
+static size_t msg_print_text(const struct log *msg, enum log_flags prev,
+                             bool syslog, char *buf, size_t size) { return 0; }
+static size_t cont_print_text(char *text, size_t size) { return 0; }
 
 #endif /* CONFIG_PRINTK */
 
@@ -1778,6 +1920,7 @@ void wake_up_klogd(void)
 /* the next printk record to write to the console */
 static u64 console_seq;
 static u32 console_idx;
+static enum log_flags console_prev;
 
 /**
  * console_unlock - unlock the console system
@@ -1795,6 +1938,7 @@ static u32 console_idx;
  */
 void console_unlock(void)
 {
+        static char text[LOG_LINE_MAX];
         static u64 seen_seq;
         unsigned long flags;
         bool wake_klogd = false;
@@ -1807,10 +1951,23 @@ void console_unlock(void)
 
         console_may_schedule = 0;
 
+        /* flush buffered message fragment immediately to console */
+        raw_spin_lock_irqsave(&logbuf_lock, flags);
+        if (cont.len && (cont.cons < cont.len || cont.flushed)) {
+                size_t len;
+
+                len = cont_print_text(text, sizeof(text));
+                raw_spin_unlock(&logbuf_lock);
+                stop_critical_timings();
+                call_console_drivers(cont.level, text, len);
+                start_critical_timings();
+                local_irq_restore(flags);
+        } else
+                raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+
 again:
         for (;;) {
                 struct log *msg;
-                static char text[LOG_LINE_MAX];
                 size_t len;
                 int level;
 
@@ -1824,18 +1981,35 @@ again:
                         /* messages are gone, move to first one */
                         console_seq = log_first_seq;
                         console_idx = log_first_idx;
+                        console_prev = 0;
                 }
-
+skip:
                 if (console_seq == log_next_seq)
                         break;
 
                 msg = log_from_idx(console_idx);
-                level = msg->level & 7;
-
-                len = msg_print_text(msg, false, text, sizeof(text));
+                if (msg->flags & LOG_NOCONS) {
+                        /*
+                         * Skip record we have buffered and already printed
+                         * directly to the console when we received it.
+                         */
+                        console_idx = log_next(console_idx);
+                        console_seq++;
+                        /*
+                         * We will get here again when we register a new
+                         * CON_PRINTBUFFER console. Clear the flag so we
+                         * will properly dump everything later.
+                         */
+                        msg->flags &= ~LOG_NOCONS;
+                        goto skip;
+                }
 
+                level = msg->level;
+                len = msg_print_text(msg, console_prev, false,
+                                     text, sizeof(text));
                 console_idx = log_next(console_idx);
                 console_seq++;
+                console_prev = msg->flags;
                 raw_spin_unlock(&logbuf_lock);
 
                 stop_critical_timings();        /* don't trace print latency */
@@ -2098,6 +2272,7 @@ void register_console(struct console *newcon)
                 raw_spin_lock_irqsave(&logbuf_lock, flags);
                 console_seq = syslog_seq;
                 console_idx = syslog_idx;
+                console_prev = syslog_prev;
                 raw_spin_unlock_irqrestore(&logbuf_lock, flags);
                 /*
                  * We're about to replay the log buffer.  Only do this to the
@@ -2391,8 +2566,7 @@ bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
         }
 
         msg = log_from_idx(dumper->cur_idx);
-        l = msg_print_text(msg, syslog,
-                              line, size);
+        l = msg_print_text(msg, 0, syslog, line, size);
 
         dumper->cur_idx = log_next(dumper->cur_idx);
         dumper->cur_seq++;
@@ -2409,7 +2583,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
  * kmsg_dump_get_buffer - copy kmsg log lines
  * @dumper: registered kmsg dumper
  * @syslog: include the "<4>" prefixes
- * @line: buffer to copy the line to
+ * @buf: buffer to copy the line to
  * @size: maximum size of the buffer
  * @len: length of line placed into buffer
  *
@@ -2432,6 +2606,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
         u32 idx;
         u64 next_seq;
         u32 next_idx;
+        enum log_flags prev;
         size_t l = 0;
         bool ret = false;
 
@@ -2454,23 +2629,27 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
         /* calculate length of entire buffer */
         seq = dumper->cur_seq;
         idx = dumper->cur_idx;
+        prev = 0;
         while (seq < dumper->next_seq) {
                 struct log *msg = log_from_idx(idx);
 
-                l += msg_print_text(msg, true, NULL, 0);
+                l += msg_print_text(msg, prev, true, NULL, 0);
                 idx = log_next(idx);
                 seq++;
+                prev = msg->flags;
         }
 
         /* move first record forward until length fits into the buffer */
         seq = dumper->cur_seq;
         idx = dumper->cur_idx;
+        prev = 0;
         while (l > size && seq < dumper->next_seq) {
                 struct log *msg = log_from_idx(idx);
 
-                l -= msg_print_text(msg, true, NULL, 0);
+                l -= msg_print_text(msg, prev, true, NULL, 0);
                 idx = log_next(idx);
                 seq++;
+                prev = msg->flags;
         }
 
         /* last message in next interation */
@@ -2478,14 +2657,14 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
         next_idx = idx;
 
         l = 0;
+        prev = 0;
         while (seq < dumper->next_seq) {
                 struct log *msg = log_from_idx(idx);
 
-                l += msg_print_text(msg, syslog,
-                                    buf + l, size - l);
-
+                l += msg_print_text(msg, prev, syslog, buf + l, size - l);
                 idx = log_next(idx);
                 seq++;
+                prev = msg->flags;
         }
 
         dumper->next_seq = next_seq;