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authorSergey Senozhatsky <sergey.senozhatsky.work@gmail.com>2018-01-11 09:53:35 +0900
committerTejun Heo <tj@kernel.org>2018-01-12 11:39:49 -0800
commit62635ea8c18f0f62df4cc58379e4f1d33afd5801 (patch)
tree31dbe0ad060063595b2c088e5d1ccd88bde93974 /kernel/workqueue.c
parent01dfee9582d9b4403c4902df096ed8b43d55181c (diff)
workqueue: avoid hard lockups in show_workqueue_state()
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 <sergey.senozhatsky@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org # v4.5+
Diffstat (limited to 'kernel/workqueue.c')
-rw-r--r--kernel/workqueue.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 43d18cb46308..f699122dab32 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"
@@ -4463,6 +4464,12 @@ 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();
}
}
@@ -4490,6 +4497,12 @@ 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();