printk: only look for prefix levels in kernel messages

vprintk_emit() prefix parsing should only be done for internal kernel
messages.  This allows existing behavior to be kept in all cases.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 15 deletions

diff --git a/kernel/printk.c b/kernel/printk.c
index 0d882a2f231e..6a76ab9d4476 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1487,7 +1487,6 @@ asmlinkage int vprintk_emit(int facility, int level,
         size_t text_len;
         enum log_flags lflags = 0;
         unsigned long flags;
-        int kern_level;
         int this_cpu;
         int printed_len = 0;
 
@@ -1543,21 +1542,24 @@ asmlinkage int vprintk_emit(int facility, int level,
                 lflags |= LOG_NEWLINE;
         }
 
-        /* strip syslog prefix and extract log level or control flags */
-        kern_level = printk_get_level(text);
-        if (kern_level) {
-                const char *end_of_header = printk_skip_level(text);
-                switch (kern_level) {
-                case '0' ... '7':
-                        if (level == -1)
-                                level = kern_level - '0';
-                case 'd':       /* KERN_DEFAULT */
-                        lflags |= LOG_PREFIX;
-                case 'c':       /* KERN_CONT */
-                        break;
+        /* strip kernel syslog prefix and extract log level or control flags */
+        if (facility == 0) {
+                int kern_level = printk_get_level(text);
+
+                if (kern_level) {
+                        const char *end_of_header = printk_skip_level(text);
+                        switch (kern_level) {
+                        case '0' ... '7':
+                                if (level == -1)
+                                        level = kern_level - '0';
+                        case 'd':       /* KERN_DEFAULT */
+                                lflags |= LOG_PREFIX;
+                        case 'c':       /* KERN_CONT */
+                                break;
+                        }
+                        text_len -= end_of_header - text;
+                        text = (char *)end_of_header;
                 }
-                text_len -= end_of_header - text;
-                text = (char *)end_of_header;
         }
 
         if (level == -1)