Commit e0348c1f authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'wq-for-6.7-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 

Pull workqueue fix from Tejun Heo:
 "Just one patch to fix a bug which can crash the kernel if the
  housekeeping and wq_unbound_cpu cpumask configuration combination
  leaves the latter empty"

* tag 'wq-for-6.7-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: Make sure that wq_unbound_cpumask is never empty
parents 4388ae22 4a6c5607

kernel/workqueue.c

+15 −7
Original line number Diff line number Diff line
@@ -1684,9 +1684,6 @@ static int wq_select_unbound_cpu(int cpu) 
		pr_warn_once("workqueue: round-robin CPU selection forced, expect performance impact\n");

	}



	if (cpumask_empty(wq_unbound_cpumask))

		return cpu;



	new_cpu = __this_cpu_read(wq_rr_cpu_last);

	new_cpu = cpumask_next_and(new_cpu, wq_unbound_cpumask, cpu_online_mask);

	if (unlikely(new_cpu >= nr_cpu_ids)) {
@@ -6515,6 +6512,17 @@ static inline void wq_watchdog_init(void) { } 


#endif	/* CONFIG_WQ_WATCHDOG */



static void __init restrict_unbound_cpumask(const char *name, const struct cpumask *mask)

{

	if (!cpumask_intersects(wq_unbound_cpumask, mask)) {

		pr_warn("workqueue: Restricting unbound_cpumask (%*pb) with %s (%*pb) leaves no CPU, ignoring\n",

			cpumask_pr_args(wq_unbound_cpumask), name, cpumask_pr_args(mask));

		return;

	}



	cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, mask);

}



/**

 * workqueue_init_early - early init for workqueue subsystem

 *
@@ -6534,11 +6542,11 @@ void __init workqueue_init_early(void) 
	BUILD_BUG_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));



	BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL));

	cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_WQ));

	cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_DOMAIN));



	cpumask_copy(wq_unbound_cpumask, cpu_possible_mask);

	restrict_unbound_cpumask("HK_TYPE_WQ", housekeeping_cpumask(HK_TYPE_WQ));

	restrict_unbound_cpumask("HK_TYPE_DOMAIN", housekeeping_cpumask(HK_TYPE_DOMAIN));

	if (!cpumask_empty(&wq_cmdline_cpumask))

		cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, &wq_cmdline_cpumask);

		restrict_unbound_cpumask("workqueue.unbound_cpus", &wq_cmdline_cpumask);



	pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);