workqueues: do CPU_UP_CANCELED if CPU_UP_PREPARE fails (8448502c) · Commits · 戴 / test

The bug was pointed out by Akinobu Mita <akinobu.mita@gmail.com>, and this patch is based on his original patch. workqueue_cpu_callback(CPU_UP_PREPARE) expects that if it returns NOTIFY_BAD, _cpu_up() will send CPU_UP_CANCELED then. However, this is not true since "cpu hotplug: cpu: deliver CPU_UP_CANCELED only to NOTIFY_OKed callbacks with CPU_UP_PREPARE" commit: The callback which has returned NOTIFY_BAD will not receive CPU_UP_CANCELED. Change the code to fulfil the CPU_UP_CANCELED logic if CPU_UP_PREPARE fails. Signed-off-by:

Oleg Nesterov <oleg@tv-sign.ru> Reported-by:

Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

kernel/workqueue.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -911,6 +911,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
		unsigned int cpu = (unsigned long)hcpu;
		struct cpu_workqueue_struct *cwq;
		struct workqueue_struct *wq;
		int ret = NOTIFY_OK;

		action &= ~CPU_TASKS_FROZEN;

		@@ -918,7 +919,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
		case CPU_UP_PREPARE:
		cpu_set(cpu, cpu_populated_map);
		}

		undo:
		list_for_each_entry(wq, &workqueues, list) {
		cwq = per_cpu_ptr(wq->cpu_wq, cpu);

		@@ -928,7 +929,9 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
		break;
		printk(KERN_ERR "workqueue [%s] for %i failed\n",
		wq->name, cpu);
		return NOTIFY_BAD;
		action = CPU_UP_CANCELED;
		ret = NOTIFY_BAD;
		goto undo;

		case CPU_ONLINE:
		start_workqueue_thread(cwq, cpu);
		@@ -948,7 +951,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
		cpu_clear(cpu, cpu_populated_map);
		}

		return NOTIFY_OK;
		return ret;
		}

		void __init init_workqueues(void)

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