dynamic_debug: Remove uses of KERN_CONT in dynamic_emit_prefix
Joe Perches [Thu, 11 Aug 2011 18:36:29 +0000 (14:36 -0400)]
Multiple printks with KERN_CONT can be interleaved by
other printks.  Reduce the likelihood of that interleaving
by consolidating multiple calls to printk.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

lib/dynamic_debug.c

index 3721709..a3eb6ab 100644 (file)
@@ -430,23 +430,35 @@ static int ddebug_exec_query(char *query_string)
 
 static int dynamic_emit_prefix(const struct _ddebug *descriptor)
 {
-       int res;
+       char tid[sizeof(int) + sizeof(int)/2 + 4];
+       char lineno[sizeof(int) + sizeof(int)/2];
 
-       res = printk(KERN_DEBUG);
        if (descriptor->flags & _DPRINTK_FLAGS_INCL_TID) {
                if (in_interrupt())
-                       res += printk(KERN_CONT "<intr> ");
+                       snprintf(tid, sizeof(tid), "%s", "<intr> ");
                else
-                       res += printk(KERN_CONT "[%d] ", task_pid_vnr(current));
+                       snprintf(tid, sizeof(tid), "[%d] ",
+                                task_pid_vnr(current));
+       } else {
+               tid[0] = 0;
        }
-       if (descriptor->flags & _DPRINTK_FLAGS_INCL_MODNAME)
-               res += printk(KERN_CONT "%s:", descriptor->modname);
-       if (descriptor->flags & _DPRINTK_FLAGS_INCL_FUNCNAME)
-               res += printk(KERN_CONT "%s:", descriptor->function);
-       if (descriptor->flags & _DPRINTK_FLAGS_INCL_LINENO)
-               res += printk(KERN_CONT "%d ", descriptor->lineno);
 
-       return res;
+       if (descriptor->flags & _DPRINTK_FLAGS_INCL_LINENO)
+               snprintf(lineno, sizeof(lineno), "%d", descriptor->lineno);
+       else
+               lineno[0] = 0;
+
+       return printk(KERN_DEBUG "%s%s%s%s%s%s",
+                     tid,
+                     (descriptor->flags & _DPRINTK_FLAGS_INCL_MODNAME) ?
+                     descriptor->modname : "",
+                     (descriptor->flags & _DPRINTK_FLAGS_INCL_MODNAME) ?
+                     ":" : "",
+                     (descriptor->flags & _DPRINTK_FLAGS_INCL_FUNCNAME) ?
+                     descriptor->function : "",
+                     (descriptor->flags & _DPRINTK_FLAGS_INCL_FUNCNAME) ?
+                     ":" : "",
+                     lineno);
 }
 
 int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)