[PATCH 1/4] printk: Re-add irqsave/restore in printk_sched

[John Stultz]

A commit in akpm's tree (printk: remove separate printk_sched
buffers...), removed the printk_sched irqsave/restore lines
since it was safe for current users. Since we may be expanding
usage of printk_sched(), re-add the irqsave/restore logic
to make the functionality more generally safe.

Cc: Jan Kara <jack@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Jiri Bohac <jbohac@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
---
 kernel/printk/printk.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 82d19e6..bf62f2b 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2586,15 +2586,18 @@ void wake_up_klogd(void)
 
 int printk_sched(const char *fmt, ...)
 {
+	unsigned long flags;
 	va_list args;
 	int r;
 
+	local_irq_save(flags);
 	va_start(args, fmt);
 	r = vprintk_emit(0, SCHED_MESSAGE_LOGLEVEL, NULL, 0, fmt, args);
 	va_end(args);
 
 	__this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
 	irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
+	local_irq_restore(flags);
 
 	return r;
 }
-- 
1.9.1

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