Hi, with lockdep enabled, I get the warning below. I've verified it and it seems to be really correct - we acquire dlm->ast_lock and lockres->spinlock in different orders in dlm_queue_bast() and dlm_lockres_release_asm(). I'm not sure whether this can really lead to a deadlock and / or how to fix this... Honza ======================================================[ INFO: possible circular locking dependency detected ] 2.6.29-rc3-default #7 ------------------------------------------------------- dlm_thread/3876 is trying to acquire lock: (&dlm->ast_lock){--..}, at: [<ffffffffa029c98d>] dlm_queue_bast+0x75/0x16c [ocfs2_dlm] but task is already holding lock: (&res->spinlock){--..}, at: [<ffffffffa028bb63>] dlm_thread+0x506/0x11fb [ocfs2_dlm] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&res->spinlock){--..}: [<ffffffff80249be9>] add_lock_to_list+0x74/0xb3 [<ffffffff8024ce4d>] __lock_acquire+0x1208/0x156e [<ffffffff80321d44>] _atomic_dec_and_lock+0x14/0x34 [<ffffffff8024d205>] lock_acquire+0x52/0x6c [<ffffffff80321d44>] _atomic_dec_and_lock+0x14/0x34 [<ffffffff80467cfd>] _spin_lock+0x29/0x36 [<ffffffff80321d44>] _atomic_dec_and_lock+0x14/0x34 [<ffffffff80321d44>] _atomic_dec_and_lock+0x14/0x34 [<ffffffffa0293e8d>] dlm_lockres_release_ast+0x20/0x9a [ocfs2_dlm] [<ffffffffa028c488>] dlm_thread+0xe2b/0x11fb [ocfs2_dlm] [<ffffffff80240db5>] autoremove_wake_function+0x0/0x2e [<ffffffff8024b388>] trace_hardirqs_on_caller+0x115/0x138 [<ffffffffa028b65d>] dlm_thread+0x0/0x11fb [ocfs2_dlm] [<ffffffff80240acd>] kthread+0x47/0x73 [<ffffffff8046782f>] trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff8020cd3a>] child_rip+0xa/0x20 [<ffffffff8020c8bc>] restore_args+0x0/0x30 [<ffffffff80240a61>] kthreadd+0x177/0x19c [<ffffffff80240a86>] kthread+0x0/0x73 [<ffffffff8020cd30>] child_rip+0x0/0x20 [<ffffffffffffffff>] 0xffffffffffffffff -> #0 (&dlm->ast_lock){--..}: [<ffffffff8024b835>] print_circular_bug_tail+0x87/0xc7 [<ffffffff8024b68f>] print_circular_bug_header+0xcc/0xd3 [<ffffffff8024cb25>] __lock_acquire+0xee0/0x156e [<ffffffff8024d205>] lock_acquire+0x52/0x6c [<ffffffffa029c98d>] dlm_queue_bast+0x75/0x16c [ocfs2_dlm] [<ffffffff80467cfd>] _spin_lock+0x29/0x36 [<ffffffffa029c98d>] dlm_queue_bast+0x75/0x16c [ocfs2_dlm] [<ffffffffa029c98d>] dlm_queue_bast+0x75/0x16c [ocfs2_dlm] [<ffffffffa028c07b>] dlm_thread+0xa1e/0x11fb [ocfs2_dlm] [<ffffffff80240db5>] autoremove_wake_function+0x0/0x2e [<ffffffff8024b388>] trace_hardirqs_on_caller+0x115/0x138 [<ffffffffa028b65d>] dlm_thread+0x0/0x11fb [ocfs2_dlm] [<ffffffff80240acd>] kthread+0x47/0x73 [<ffffffff8046782f>] trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff8020cd3a>] child_rip+0xa/0x20 [<ffffffff8020c8bc>] restore_args+0x0/0x30 [<ffffffff80240a61>] kthreadd+0x177/0x19c [<ffffffff80240a86>] kthread+0x0/0x73 [<ffffffff8020cd30>] child_rip+0x0/0x20 [<ffffffffffffffff>] 0xffffffffffffffff other info that might help us debug this: 1 lock held by dlm_thread/3876: #0: (&res->spinlock){--..}, at: [<ffffffffa028bb63>] dlm_thread+0x506/0x11fb [ocfs2_dlm] stack backtrace: Pid: 3876, comm: dlm_thread Not tainted 2.6.29-rc3-default #7 Call Trace: [<ffffffff8024b86c>] print_circular_bug_tail+0xbe/0xc7 [<ffffffff8024b68f>] print_circular_bug_header+0xcc/0xd3 [<ffffffff8024cb25>] __lock_acquire+0xee0/0x156e [<ffffffff8024d205>] lock_acquire+0x52/0x6c [<ffffffffa029c98d>] dlm_queue_bast+0x75/0x16c [ocfs2_dlm] [<ffffffff80467cfd>] _spin_lock+0x29/0x36 [<ffffffffa029c98d>] dlm_queue_bast+0x75/0x16c [ocfs2_dlm] [<ffffffffa029c98d>] dlm_queue_bast+0x75/0x16c [ocfs2_dlm] [<ffffffffa028c07b>] dlm_thread+0xa1e/0x11fb [ocfs2_dlm] [<ffffffff80240db5>] autoremove_wake_function+0x0/0x2e [<ffffffff8024b388>] trace_hardirqs_on_caller+0x115/0x138 [<ffffffffa028b65d>] dlm_thread+0x0/0x11fb [ocfs2_dlm] [<ffffffff80240acd>] kthread+0x47/0x73 [<ffffffff8046782f>] trace_hardirqs_on_thunk+0x3a/0x3f [<ffffffff8020cd3a>] child_rip+0xa/0x20 [<ffffffff8020c8bc>] restore_args+0x0/0x30 [<ffffffff80240a61>] kthreadd+0x177/0x19c [<ffffffff80240a86>] kthread+0x0/0x73 [<ffffffff8020cd30>] child_rip+0x0/0x20 Honza