printk: disable preemption for printk_sched

An earlier change in -mm (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(), disable preepmtion for this function to make it more generally safe to call. Signed-off-by: John Stultz <[email protected]> Reviewed-by: Jan Kara <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Jiri Bohac <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Steven Rostedt <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
ambv · Jun 4, 2014 · 8195460 · 8195460
1 parent 458df9f
commit 8195460
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
@@ -2590,12 +2590,14 @@ int printk_sched(const char *fmt, ...)
 	va_list args;
 	int r;
 
+	preempt_disable();
 	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));
+	preempt_enable();
 
 	return r;
 }