When watchdog detects a hardlockup and calls nmi_panic() `printk_func'
must be restored via printk_nmi_exit() call, so panic() will be able
to flush nmi buf and show backtrace and panic message. We also better
explicitly ask nmi to printk_nmi_flush() in console_flush_on_panic(),
because it may be too late to rely on irq work.
Signed-off-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
---
include/linux/kernel.h | 6 ++++--
kernel/printk/printk.c | 1 +
2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index f4fa2b2..3ee33d5 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -469,10 +469,12 @@ do {
\
cpu = raw_smp_processor_id(); \
old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, cpu); \
\
- if (old_cpu == PANIC_CPU_INVALID) \
+ if (old_cpu == PANIC_CPU_INVALID) { \
+ printk_nmi_exit(); \
panic(fmt, ##__VA_ARGS__); \
- else if (old_cpu != cpu) \
+ } else if (old_cpu != cpu) { \
nmi_panic_self_stop(regs); \
+ } \
} while (0)
/*
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 9917f69..13a4022 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2395,6 +2395,7 @@ void console_flush_on_panic(void)
*/
console_trylock();
console_may_schedule = 0;
+ printk_nmi_flush();
console_unlock();
}
--
2.7.1
