Merge branch 'linus' into perf/core, to refresh the branch

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 12 insertions, 19 deletions

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index bfbf284e4218..60cdf6386763 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -55,6 +55,7 @@
 
 #include "console_cmdline.h"
 #include "braille.h"
+#include "internal.h"
 
 int console_printk[4] = {
 	CONSOLE_LOGLEVEL_DEFAULT,	/* console_loglevel */
@@ -244,7 +245,7 @@ __packed __aligned(4)
  * within the scheduler's rq lock. It must be released before calling
  * console_unlock() or anything else that might wake up a process.
  */
-static DEFINE_RAW_SPINLOCK(logbuf_lock);
+DEFINE_RAW_SPINLOCK(logbuf_lock);
 
 #ifdef CONFIG_PRINTK
 DECLARE_WAIT_QUEUE_HEAD(log_wait);
@@ -1616,6 +1617,7 @@ asmlinkage int vprintk_emit(int facility, int level,
 	unsigned long flags;
 	int this_cpu;
 	int printed_len = 0;
+	int nmi_message_lost;
 	bool in_sched = false;
 	/* cpu currently holding logbuf_lock in this function */
 	static unsigned int logbuf_cpu = UINT_MAX;
@@ -1666,6 +1668,15 @@ asmlinkage int vprintk_emit(int facility, int level,
 					 strlen(recursion_msg));
 	}
 
+	nmi_message_lost = get_nmi_message_lost();
+	if (unlikely(nmi_message_lost)) {
+		text_len = scnprintf(textbuf, sizeof(textbuf),
+				     "BAD LUCK: lost %d message(s) from NMI context!",
+				     nmi_message_lost);
+		printed_len += log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0,
+					 NULL, 0, textbuf, text_len);
+	}
+
 	/*
 	 * The printf needs to come first; we need the syslog
 	 * prefix which might be passed-in as a parameter.
@@ -1807,14 +1818,6 @@ int vprintk_default(const char *fmt, va_list args)
 }
 EXPORT_SYMBOL_GPL(vprintk_default);
 
-/*
- * This allows printk to be diverted to another function per cpu.
- * This is useful for calling printk functions from within NMI
- * without worrying about race conditions that can lock up the
- * box.
- */
-DEFINE_PER_CPU(printk_func_t, printk_func) = vprintk_default;
-
 /**
  * printk - print a kernel message
  * @fmt: format string
@@ -1838,21 +1841,11 @@ DEFINE_PER_CPU(printk_func_t, printk_func) = vprintk_default;
  */
 asmlinkage __visible int printk(const char *fmt, ...)
 {
-	printk_func_t vprintk_func;
 	va_list args;
 	int r;
 
 	va_start(args, fmt);
-
-	/*
-	 * If a caller overrides the per_cpu printk_func, then it needs
-	 * to disable preemption when calling printk(). Otherwise
-	 * the printk_func should be set to the default. No need to
-	 * disable preemption here.
-	 */
-	vprintk_func = this_cpu_read(printk_func);
 	r = vprintk_func(fmt, args);
-
 	va_end(args);
 
 	return r;