123 lines
3.4 KiB
Diff
123 lines
3.4 KiB
Diff
From 66f77c2964b6862977bc171baff5e3a012b3c5a8 Mon Sep 17 00:00:00 2001
|
|
From: Ingo Molnar <mingo@elte.hu>
|
|
Date: Fri, 22 Jul 2011 17:58:40 +0200
|
|
Subject: [PATCH 075/287] printk-kill.patch
|
|
|
|
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
---
|
|
include/linux/printk.h | 3 ++-
|
|
kernel/printk.c | 33 +++++++++++++++++++++++++++++++++
|
|
kernel/watchdog.c | 15 +++++++++++++--
|
|
3 files changed, 48 insertions(+), 3 deletions(-)
|
|
|
|
diff --git a/include/linux/printk.h b/include/linux/printk.h
|
|
index be10455..a53adf6 100644
|
|
--- a/include/linux/printk.h
|
|
+++ b/include/linux/printk.h
|
|
@@ -91,9 +91,11 @@ int no_printk(const char *fmt, ...)
|
|
#ifdef CONFIG_EARLY_PRINTK
|
|
extern asmlinkage __printf(1, 2)
|
|
void early_printk(const char *fmt, ...);
|
|
+extern void printk_kill(void);
|
|
#else
|
|
static inline __printf(1, 2) __cold
|
|
void early_printk(const char *s, ...) { }
|
|
+static inline void printk_kill(void) { }
|
|
#endif
|
|
|
|
extern int printk_needs_cpu(int cpu);
|
|
@@ -114,7 +116,6 @@ extern int __printk_ratelimit(const char *func);
|
|
#define printk_ratelimit() __printk_ratelimit(__func__)
|
|
extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
|
|
unsigned int interval_msec);
|
|
-
|
|
extern int printk_delay_msec;
|
|
extern int dmesg_restrict;
|
|
extern int kptr_restrict;
|
|
diff --git a/kernel/printk.c b/kernel/printk.c
|
|
index b7aa50e..96ee3cd 100644
|
|
--- a/kernel/printk.c
|
|
+++ b/kernel/printk.c
|
|
@@ -532,6 +532,32 @@ asmlinkage void early_printk(const char *fmt, ...)
|
|
early_vprintk(fmt, ap);
|
|
va_end(ap);
|
|
}
|
|
+
|
|
+/*
|
|
+ * This is independent of any log levels - a global
|
|
+ * kill switch that turns off all of printk.
|
|
+ *
|
|
+ * Used by the NMI watchdog if early-printk is enabled.
|
|
+ */
|
|
+static int __read_mostly printk_killswitch;
|
|
+
|
|
+void printk_kill(void)
|
|
+{
|
|
+ printk_killswitch = 1;
|
|
+}
|
|
+
|
|
+static int forced_early_printk(const char *fmt, va_list ap)
|
|
+{
|
|
+ if (!printk_killswitch)
|
|
+ return 0;
|
|
+ early_vprintk(fmt, ap);
|
|
+ return 1;
|
|
+}
|
|
+#else
|
|
+static inline int forced_early_printk(const char *fmt, va_list ap)
|
|
+{
|
|
+ return 0;
|
|
+}
|
|
#endif
|
|
|
|
static int __read_mostly ignore_loglevel;
|
|
@@ -850,6 +876,13 @@ asmlinkage int vprintk(const char *fmt, va_list args)
|
|
size_t plen;
|
|
char special;
|
|
|
|
+ /*
|
|
+ * Fall back to early_printk if a debugging subsystem has
|
|
+ * killed printk output
|
|
+ */
|
|
+ if (unlikely(forced_early_printk(fmt, args)))
|
|
+ return 1;
|
|
+
|
|
boot_delay_msec();
|
|
printk_delay();
|
|
|
|
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
|
|
index 1d7bca7..c7e2a2f 100644
|
|
--- a/kernel/watchdog.c
|
|
+++ b/kernel/watchdog.c
|
|
@@ -201,6 +201,8 @@ static int is_softlockup(unsigned long touch_ts)
|
|
|
|
#ifdef CONFIG_HARDLOCKUP_DETECTOR
|
|
|
|
+static DEFINE_RAW_SPINLOCK(watchdog_output_lock);
|
|
+
|
|
static struct perf_event_attr wd_hw_attr = {
|
|
.type = PERF_TYPE_HARDWARE,
|
|
.config = PERF_COUNT_HW_CPU_CYCLES,
|
|
@@ -235,10 +237,19 @@ static void watchdog_overflow_callback(struct perf_event *event,
|
|
if (__this_cpu_read(hard_watchdog_warn) == true)
|
|
return;
|
|
|
|
- if (hardlockup_panic)
|
|
+ /*
|
|
+ * If early-printk is enabled then make sure we do not
|
|
+ * lock up in printk() and kill console logging:
|
|
+ */
|
|
+ printk_kill();
|
|
+
|
|
+ if (hardlockup_panic) {
|
|
panic("Watchdog detected hard LOCKUP on cpu %d", this_cpu);
|
|
- else
|
|
+ } else {
|
|
+ raw_spin_lock(&watchdog_output_lock);
|
|
WARN(1, "Watchdog detected hard LOCKUP on cpu %d", this_cpu);
|
|
+ raw_spin_unlock(&watchdog_output_lock);
|
|
+ }
|
|
|
|
__this_cpu_write(hard_watchdog_warn, true);
|
|
return;
|