Commit 4c0736a7 authored by Petr Mladek's avatar Petr Mladek Committed by Tejun Heo

workqueue: Warn when a rescuer could not be created

Rescuers are created when a workqueue with WQ_MEM_RECLAIM is allocated.
It typically happens during the system boot.

systemd switches the root filesystem from initrd to the booted system
during boot. It kills processes that block the switch for too long.
One of the process might be modprobe that tries to create a workqueue.

These problems are hard to reproduce. Also alloc_workqueue() does not
pass the error code. Make the debugging easier by printing an error,
similar to create_worker().
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 60f54038
...@@ -4391,13 +4391,18 @@ static int init_rescuer(struct workqueue_struct *wq) ...@@ -4391,13 +4391,18 @@ static int init_rescuer(struct workqueue_struct *wq)
return 0; return 0;
rescuer = alloc_worker(NUMA_NO_NODE); rescuer = alloc_worker(NUMA_NO_NODE);
if (!rescuer) if (!rescuer) {
pr_err("workqueue: Failed to allocate a rescuer for wq \"%s\"\n",
wq->name);
return -ENOMEM; return -ENOMEM;
}
rescuer->rescue_wq = wq; rescuer->rescue_wq = wq;
rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", wq->name); rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", wq->name);
if (IS_ERR(rescuer->task)) { if (IS_ERR(rescuer->task)) {
ret = PTR_ERR(rescuer->task); ret = PTR_ERR(rescuer->task);
pr_err("workqueue: Failed to create a rescuer kthread for wq \"%s\": %pe",
wq->name, ERR_PTR(ret));
kfree(rescuer); kfree(rescuer);
return ret; return ret;
} }
......
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