Subject : 2.6.34: dlm: possible circular locking dependency detected
Submitter : CaT <email@example.com>
Date : 2010-05-21 6:59
Message-ID : 20100521065933.GH2657@zip.com.au
References : http://marc.info/?l=linux-kernel&m=127442519608471&w=2
This entry is being used for tracking a regression from 2.6.33. Please don't
close it until the problem is fixed in the mainline.
This also happens with 126.96.36.199.
I don't know the policy in for the stable kernel or for bugzilla, but this was fixed in 2.6.35. The commit is:
Author: Wengang Wang <firstname.lastname@example.org>
Date: Mon May 17 20:20:44 2010 +0800
ocfs2:dlm: avoid dlm->ast_lock lockres->spinlock dependency break
Currently we process a dirty lockres with the lockres->spinlock taken. While
during the process, we may need to lock on dlm->ast_lock. This breaks the
dependency of dlm->ast_lock(lock first) and lockres->spinlock(lock second).
This patch fixes the problem.
Since we can't release lockres->spinlock, we have to take dlm->ast_lock
just before taking the lockres->spinlock and release it after lockres->spinlock
is released. And use __dlm_queue_bast()/__dlm_queue_ast(), the nolock version,
in dlm_shuffle_lists(). There are no too many locks on a lockres, so there is no
Signed-off-by: Wengang Wang <email@example.com>
Signed-off-by: Joel Becker <firstname.lastname@example.org>
The problem has been fixed in mainline, so closing.
Please send an inclusion request to email@example.com so that it goes to -stable.