[PATCH 1/2] printk: introduce console_sync_mode

[Sergey Senozhatsky]

console_sync_mode() should be called early in panic() to switch
printk from async mode to sync. Otherwise, STOP IPIs can arrive
to other CPUs too late and those CPUs will see oops_in_progress
being 0 again.
---
 include/linux/console.h | 1 +
 kernel/panic.c          | 1 +
 kernel/printk/printk.c  | 5 +++++
 3 files changed, 7 insertions(+)

diff --git a/include/linux/console.h b/include/linux/console.h
index bd19434..f068985 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -150,6 +150,7 @@ extern int console_trylock(void);
 extern void console_unlock(void);
 extern void console_conditional_schedule(void);
 extern void console_unblank(void);
+extern void console_sync_mode(void);
 extern struct tty_driver *console_device(int *);
 extern void console_stop(struct console *);
 extern void console_start(struct console *);
diff --git a/kernel/panic.c b/kernel/panic.c
index b333380..04c8ff4 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -117,6 +117,7 @@ void panic(const char *fmt, ...)
 	if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu)
 		panic_smp_self_stop();
 
+	console_sync_mode();
 	console_verbose();
 	bust_spinlocks(1);
 	va_start(args, fmt);
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index de9d31b..47a70a2 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2501,6 +2501,11 @@ void console_unblank(void)
 	console_unlock();
 }
 
+void console_sync_mode(void)
+{
+	printk_sync = true;
+}
+
 /*
  * Return the console tty driver structure and its associated index
  */
-- 
2.6.4


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Content-Disposition: attachment; filename="0002-printk-factor-out-can_printk_async.patch"