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From: Hillf Danton <hdanton@sina.com>
To: Sam Sun <samsun1006219@gmail.com>
Cc: linux-kernel@vger.kernel.org,
	linux-block@vger.kernel.org,
	axboe@kernel.dk,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	syzkaller-bugs@googlegroups.com,
	xrivendell7@gmail.com
Subject: Re: [Linux kernel bug] INFO: task hung in blk_mq_get_tag
Date: Tue, 14 May 2024 06:54:09 +0800
Message-Id: <20240513225409.3025-1-hdanton@sina.com>
In-Reply-To: <CAEkJfYPxWBfEnuKeCGEsscVTYy8MrNxCJwdbxS=c2-B0H+HfTA@mail.gmail.com>
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On Mon, 13 May 2024 20:57:44 +0800 Sam Sun <samsun1006219@gmail.com>
> 
> I am happy to help testing patches. As

Thanks.

> for repro, I have a C repro available, but it is too long so that I
> attached it to the first email. Should I just paste repro with bug
> report?

Yes.

> I applied this patch and tried using the C repro, but it still crashed
> with the same task hang kernel dump log.

Oh low-hanging pear is sour, and try again seeing if there is missing
wakeup due to wake batch.

--- x/lib/sbitmap.c
+++ y/lib/sbitmap.c
@@ -579,6 +579,8 @@ void sbitmap_queue_wake_up(struct sbitma
 	unsigned int wake_batch = READ_ONCE(sbq->wake_batch);
 	unsigned int wakeups;
 
+	__sbitmap_queue_wake_up(sbq, nr);
+
 	if (!atomic_read(&sbq->ws_active))
 		return;
 
--