redonkable/alistair23-linux
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Merge branch 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

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Pull workqueue fixlet from Tejun Heo:
 "One patch to add touch_nmi_watchdog() while dumping workqueue debug
  messages to avoid triggering the lockup detector spuriously.

  The change is very low risk"

* 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: avoid hard lockups in show_workqueue_state()
This commit is contained in:
Linus Torvalds 2018-01-19 11:23:39 -08:00
parent 6ec8765f55 62635ea8c1
commit a2c9c1c035
1 changed files with 13 additions and 0 deletions
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13
kernel/workqueue.c
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@ -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();