Merge tag 'wq-for-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

Pull workqueue updates from Tejun Heo:

 - When per-cpu workqueue workers expire after sitting idle for too
   long, they used to wake up to the CPU that they're bound to in order
   to exit. This unfortunately could cause unwanted disturbances on CPUs
   isolated for e.g. RT applications.

   The worker exit path is restructured so that an existing worker is
   unbound from its CPU before being woken up for the last time,
   allowing it to migrate away from an isolated CPU for exiting.

 - A couple debug improvements. Watchdog dump is made more compact and
   workqueue now warns if used-after-free during the RCU grace period
   after destroy_workqueue().

* tag 'wq-for-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: Fold rebind_worker() within rebind_workers()
  workqueue: Unbind kworkers before sending them to exit()
  workqueue: Don't hold any lock while rcuwait'ing for !POOL_MANAGER_ACTIVE
  workqueue: Convert the idle_timer to a timer + work_struct
  workqueue: Factorize unbind/rebind_workers() logic
  workqueue: Protects wq_unbound_cpumask with wq_pool_attach_mutex
  workqueue: Make show_pwq() use run-length encoding
  workqueue: Add a new flag to spot the potential UAF error

include/linux/workqueue.h

@@ -335,6 +335,7 @@ enum {
 	 */
 	WQ_POWER_EFFICIENT	= 1 << 7,
 
+	__WQ_DESTROYING		= 1 << 15, /* internal: workqueue is destroying */
 	__WQ_DRAINING		= 1 << 16, /* internal: workqueue is draining */
 	__WQ_ORDERED		= 1 << 17, /* internal: workqueue is ordered */
 	__WQ_LEGACY		= 1 << 18, /* internal: create*_workqueue() */