show_workqueue_state() can print out a lot of messages while being in atomic context, e.g. sysrq-t -> show_workqueue_state(). If the console device is slow it may end up triggering NMI hard lockup watchdog.
Signed-off-by: Sergey Senozhatsky <[email protected]> --- kernel/workqueue.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 9960f8842b31..8dd2e66e8383 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -48,6 +48,7 @@ #include <linux/moduleparam.h> #include <linux/uaccess.h> #include <linux/sched/isolation.h> +#include <linux/nmi.h> #include "workqueue_internal.h" @@ -4473,6 +4474,12 @@ void show_workqueue_state(void) if (pwq->nr_active || !list_empty(&pwq->delayed_works)) show_pwq(pwq); spin_unlock_irqrestore(&pwq->pool->lock, flags); + /* + * We could be printing a lot from atomic context, e.g. + * sysrq-t -> show_workqueue_state(). Avoid triggering + * hard lockup. + */ + touch_nmi_watchdog(); } } @@ -4500,6 +4507,12 @@ void show_workqueue_state(void) pr_cont("\n"); next_pool: spin_unlock_irqrestore(&pool->lock, flags); + /* + * We could be printing a lot from atomic context, e.g. + * sysrq-t -> show_workqueue_state(). Avoid triggering + * hard lockup. + */ + touch_nmi_watchdog(); } rcu_read_unlock_sched(); -- 2.15.1
