1 files changed, 37 insertions, 14 deletions

diff --git a/kernel/printk.c b/kernel/printk.c
index ff05361962e1..cdfba44fedf0 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -862,26 +862,49 @@ 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;
+
+                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;
+                }
+                if (syslog_seq == log_next_seq) {
+                        raw_spin_unlock_irq(&logbuf_lock);
+                        break;
+                }
+                msg = log_from_idx(syslog_idx);
+                n = msg_print_text(msg, true, text, LOG_LINE_MAX);
+                if (n <= size) {
+                        syslog_idx = log_next(syslog_idx);
+                        syslog_seq++;
+                } else
+                        n = 0;
+                raw_spin_unlock_irq(&logbuf_lock);
+
+                if (!n)
+                        break;
 
-        if (len > 0 && copy_to_user(buf, text, len))
-                len = -EFAULT;
+                len += n;
+                size -= n;
+                buf += n;
+                n = copy_to_user(buf - n, text, n);
+
+                if (n) {
+                        len -= n;
+                        if (!len)
+                                len = -EFAULT;
+                        break;
+                }
+        }
 
         kfree(text);
         return len;