From: Junxiao Bi <junxiao.bi@oracle.com>
To: ocfs2-devel@oss.oracle.com
Subject: [Ocfs2-devel] [PATCH] ocfs2: dlm: fix recursive locking deadlock
Date: Mon, 14 Dec 2015 14:03:17 +0800 [thread overview]
Message-ID: <566E5BA5.5030308@oracle.com> (raw)
In-Reply-To: <566EC6A8020000F90002219D@relay2.provo.novell.com>
On 12/14/2015 01:39 PM, Gang He wrote:
> Hello Junxiao,
>
> From the initial description, the second lock_XYZ(PR) should be blocked, since DLM have a fair queue mechanism, otherwise, it looks to bring a write lock starvation.
Should be blocked? No, that is a deadlock. I don't think this recursive
locking is common, so no need care starvation here.
> Second, this issue can be reproduced in old Linux kernels (e.g. 3.16.7-24)? there should not be any regression issue?
Maybe just hard to reproduce, ocfs2 supports recursive locking.
> Finally, really do not like nested using lock, can we avoid this.
I didn't see a good reason why this should be avoided. Without this,
developer needs pay more attend to not involve recursive locking,
usually that is very hard before run a full test or a very detailed review.
Thanks,
Junxiao.
>
> Thanks
> Gang
>
>
next prev parent reply other threads:[~2015-12-14 6:03 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-14 1:57 [Ocfs2-devel] [PATCH] ocfs2: dlm: fix recursive locking deadlock Junxiao Bi
2015-12-14 5:39 ` Gang He
2015-12-14 6:03 ` Junxiao Bi [this message]
2015-12-14 8:57 ` Eric Ren
2015-12-14 15:07 ` Junxiao Bi
2015-12-14 19:18 ` Mark Fasheh
2015-12-15 1:43 ` Junxiao Bi
2015-12-18 23:23 ` Mark Fasheh
2015-12-21 5:12 ` Junxiao Bi
2015-12-22 22:12 ` Mark Fasheh
2015-12-23 2:18 ` Junxiao Bi
2015-12-14 8:44 ` Eric Ren
2015-12-14 9:02 ` Junxiao Bi
2015-12-14 10:14 ` Eric Ren
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