[PATCH 1/3] printk: Fix kdb_trap_printk placement

[Peter Zijlstra]

Some people figured vprintk_emit() makes for a nice API and exported
it, bypassing the kdb trap.

This still leaves vprintk_nmi() outside of the kbd reach, should that
be fixed too?

Cc: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
 kernel/printk/printk.c |   19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1750,6 +1750,13 @@ asmlinkage int vprintk_emit(int facility
 	/* cpu currently holding logbuf_lock in this function */
 	static unsigned int logbuf_cpu = UINT_MAX;
 
+#ifdef CONFIG_KGDB_KDB
+	if (unlikely(kdb_trap_printk)) {
+		r = vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args);
+		return r;
+	}
+#endif
+
 	if (level == LOGLEVEL_SCHED) {
 		level = LOGLEVEL_DEFAULT;
 		in_sched = true;
@@ -1932,17 +1939,7 @@ EXPORT_SYMBOL(printk_emit);
 
 int vprintk_default(const char *fmt, va_list args)
 {
-	int r;
-
-#ifdef CONFIG_KGDB_KDB
-	if (unlikely(kdb_trap_printk)) {
-		r = vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args);
-		return r;
-	}
-#endif
-	r = vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args);
-
-	return r;
+	return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args);
 }
 EXPORT_SYMBOL_GPL(vprintk_default);