From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Beregalov Subject: 2.6.29-rc4: possible circular locking dependency at btrfs_try_spin_lock Date: Mon, 9 Feb 2009 15:43:50 +0300 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 To: linux-btrfs@vger.kernel.org, LKML Return-path: List-ID: Hi Is it false positive lockdep warning? [ INFO: possible circular locking dependency detected ] 2.6.29-rc4-00001-gd5b5623 #2 ------------------------------------------------------- dbench/2193 is trying to acquire lock: (&eb->lock/7){--..}, at: [] btrfs_try_spin_lock+0x8f/0x1a0 but task is already holding lock: (&eb->lock#2/6){--..}, at: [] btrfs_tree_lock+0xc4/0x160 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&eb->lock#2/6){--..}: [] __lock_acquire+0xe23/0x1290 [] lock_acquire+0x91/0xc0 [] _spin_lock_nested+0x46/0x80 [] btrfs_clear_lock_blocking+0x9d/0xb0 [] btrfs_clear_path_blocking+0x32/0x50 [] btrfs_search_slot+0x9a2/0xb10 [] btrfs_insert_empty_items+0xa4/0x4e0 [] btrfs_new_inode+0x156/0x350 [] btrfs_mkdir+0x10f/0x210 [] vfs_mkdir+0x8c/0xd0 [] sys_mkdirat+0x106/0x120 [] sys_mkdir+0x13/0x20 [] system_call_fastpath+0x16/0x1b [] 0xffffffffffffffff -> #0 (&eb->lock/7){--..}: [] __lock_acquire+0xeea/0x1290 [] lock_acquire+0x91/0xc0 [] _spin_lock_nested+0x46/0x80 [] btrfs_try_spin_lock+0x8f/0x1a0 [] btrfs_search_slot+0x50e/0xb10 [] btrfs_lookup_xattr+0x83/0x110 [] __btrfs_getxattr+0x74/0x120 [] btrfs_get_acl+0xbc/0x160 [] btrfs_init_acl+0x9d/0x180 [] btrfs_init_inode_security+0x1c/0x40 [] btrfs_mkdir+0x158/0x210 [] vfs_mkdir+0x8c/0xd0 [] sys_mkdirat+0x106/0x120 [] sys_mkdir+0x13/0x20 [] system_call_fastpath+0x16/0x1b [] 0xffffffffffffffff other info that might help us debug this: 2 locks held by dbench/2193: #0: (&sb->s_type->i_mutex_key#12/1){--..}, at: [] lookup_create+0x30/0xd0 #1: (&eb->lock#2/6){--..}, at: [] btrfs_tree_lock+0xc4/0x160 stack backtrace: Pid: 2193, comm: dbench Not tainted 2.6.29-rc4-00001-gd5b5623 #2 Call Trace: [] print_circular_bug_tail+0xa7/0x100 [] __lock_acquire+0xeea/0x1290 [] lock_acquire+0x91/0xc0 [] ? btrfs_try_spin_lock+0x8f/0x1a0 [] _spin_lock_nested+0x46/0x80 [] ? btrfs_try_spin_lock+0x8f/0x1a0 [] btrfs_try_spin_lock+0x8f/0x1a0 [] btrfs_search_slot+0x50e/0xb10 [] ? crypto_shash_update+0x25/0x30 [] ? crc32c+0x4c/0x60 [] btrfs_lookup_xattr+0x83/0x110 [] ? kmem_cache_alloc+0xb5/0x100 [] ? trace_hardirqs_on+0xd/0x10 [] __btrfs_getxattr+0x74/0x120 [] btrfs_get_acl+0xbc/0x160 [] btrfs_init_acl+0x9d/0x180 [] ? mutex_unlock+0x9/0x10 [] btrfs_init_inode_security+0x1c/0x40 [] btrfs_mkdir+0x158/0x210 [] vfs_mkdir+0x8c/0xd0 [] sys_mkdirat+0x106/0x120 [] ? sysret_check+0x27/0x62 [] ? sysret_check+0x27/0x62 [] ? trace_hardirqs_on_caller+0x182/0x1e0 [] sys_mkdir+0x13/0x20 [] system_call_fastpath+0x16/0x1b