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* [PATCH] io_uring/io-wq: don't clear PF_IO_WORKER on exit
@ 2023-06-12 18:11 Jens Axboe
  2023-06-14  0:54 ` Zorro Lang
  0 siblings, 1 reply; 9+ messages in thread
From: Jens Axboe @ 2023-06-12 18:11 UTC (permalink / raw)
  To: io-uring, LKML; +Cc: Linus Torvalds, Dave Chinner, Zorro Lang

A recent commit gated the core dumping task exit logic on current->flags
remaining consistent in terms of PF_{IO,USER}_WORKER at task exit time.
This exposed a problem with the io-wq handling of that, which explicitly
clears PF_IO_WORKER before calling do_exit().

The reasons for this manual clear of PF_IO_WORKER is historical, where
io-wq used to potentially trigger a sleep on exit. As the io-wq thread
is exiting, it should not participate any further accounting. But these
days we don't need to rely on current->flags anymore, so we can safely
remove the PF_IO_WORKER clearing.

Reported-by: Zorro Lang <[email protected]>
Reported-by: Dave Chinner <[email protected]>
Reported-by: Linus Torvalds <[email protected]>
Link: https://lore.kernel.org/all/[email protected]/
Fixes: f9010dbdce91 ("fork, vhost: Use CLONE_THREAD to fix freezer/ps regression")
Signed-off-by: Jens Axboe <[email protected]>

---

diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c
index b2715988791e..fe38eb0cbc82 100644
--- a/io_uring/io-wq.c
+++ b/io_uring/io-wq.c
@@ -221,9 +221,6 @@ static void io_worker_exit(struct io_worker *worker)
 	raw_spin_unlock(&wq->lock);
 	io_wq_dec_running(worker);
 	worker->flags = 0;
-	preempt_disable();
-	current->flags &= ~PF_IO_WORKER;
-	preempt_enable();
 
 	kfree_rcu(worker, rcu);
 	io_worker_ref_put(wq);

-- 
Jens Axboe


^ permalink raw reply related	[flat|nested] 9+ messages in thread
end of thread, other threads:[~2023-06-15  2:23 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-06-12 18:11 [PATCH] io_uring/io-wq: don't clear PF_IO_WORKER on exit Jens Axboe
2023-06-14  0:54 ` Zorro Lang
2023-06-14  1:03   ` Zorro Lang
2023-06-14  1:14   ` Jens Axboe
2023-06-14  4:49     ` Zorro Lang
2023-06-14 17:44     ` Linus Torvalds
2023-06-14 19:25       ` Jens Axboe
2023-06-15  2:22     ` Zorro Lang
2023-06-15  2:23       ` Jens Axboe

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