From b845b517b5e3706a3729f6ea83b88ab85f0725b0 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 8 Aug 2008 21:47:09 +0200 Subject: printk: robustify printk Avoid deadlocks against rq->lock and xtime_lock by deferring the klogd wakeup by polling from the timer tick. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/printk.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) (limited to 'kernel/printk.c') diff --git a/kernel/printk.c b/kernel/printk.c index b51b156..655cc2c 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -982,10 +982,25 @@ int is_console_locked(void) return console_locked; } -void wake_up_klogd(void) +static DEFINE_PER_CPU(int, printk_pending); + +void printk_tick(void) { - if (!oops_in_progress && waitqueue_active(&log_wait)) + if (__get_cpu_var(printk_pending)) { + __get_cpu_var(printk_pending) = 0; wake_up_interruptible(&log_wait); + } +} + +int printk_needs_cpu(int cpu) +{ + return per_cpu(printk_pending, cpu); +} + +void wake_up_klogd(void) +{ + if (waitqueue_active(&log_wait)) + __get_cpu_var(printk_pending) = 1; } /** -- cgit v1.1