Messages in this thread | | | Date | Wed, 2 Jul 2008 15:31:59 -0700 | From | "Paul Menage" <> | Subject | Re: [RFC][PATCH] CGroups: Add a per-subsystem hierarchy lock |
| |
On Tue, Jul 1, 2008 at 8:55 PM, Max Krasnyansky <maxk@qualcomm.com> wrote: > I was about to say "yeah, looks good" and then tried a couple of > different hot-plug scenarious. > We still have circular locking even with your patch >
What sequence of actions do you do? I've not been able to reproduce a lockdep failure.
Paul
> [ INFO: possible circular locking dependency detected ] > 2.6.26-rc8 #4 > ------------------------------------------------------- > bash/2779 is trying to acquire lock: > (&cpu_hotplug.lock){--..}, at: [<ffffffff8025e024>] get_online_cpus+0x24/0x40 > > but task is already holding lock: > (sched_domains_mutex){--..}, at: [<ffffffff8022f5e9>] > partition_sched_domains+0x29/0x2b0 > > which lock already depends on the new lock. > > the existing dependency chain (in reverse order) is: > > -> #2 (sched_domains_mutex){--..}: > [<ffffffff8025988f>] __lock_acquire+0x9cf/0xe50 > [<ffffffff80259d6b>] lock_acquire+0x5b/0x80 > [<ffffffff804d12c4>] mutex_lock_nested+0x94/0x250 > [<ffffffff8022f5e9>] partition_sched_domains+0x29/0x2b0 > [<ffffffff80268f9d>] rebuild_sched_domains+0x9d/0x3f0 > [<ffffffff80269f05>] cpuset_handle_cpuhp+0x205/0x220 > [<ffffffff804d688f>] notifier_call_chain+0x3f/0x80 > [<ffffffff80250679>] __raw_notifier_call_chain+0x9/0x10 > [<ffffffff804c1748>] _cpu_down+0xa8/0x290 > [<ffffffff804c196b>] cpu_down+0x3b/0x60 > [<ffffffff804c2c68>] store_online+0x48/0xa0 > [<ffffffff803a46c4>] sysdev_store+0x24/0x30 > [<ffffffff802eebba>] sysfs_write_file+0xca/0x140 > [<ffffffff8029cb3b>] vfs_write+0xcb/0x170 > [<ffffffff8029ccd0>] sys_write+0x50/0x90 > [<ffffffff8020b92b>] system_call_after_swapgs+0x7b/0x80 > [<ffffffffffffffff>] 0xffffffffffffffff > > -> #1 (&ss->hierarchy_mutex){--..}: > [<ffffffff8025988f>] __lock_acquire+0x9cf/0xe50 > [<ffffffff80259d6b>] lock_acquire+0x5b/0x80 > [<ffffffff804d12c4>] mutex_lock_nested+0x94/0x250 > [<ffffffff80269d39>] cpuset_handle_cpuhp+0x39/0x220 > [<ffffffff804d688f>] notifier_call_chain+0x3f/0x80 > [<ffffffff80250679>] __raw_notifier_call_chain+0x9/0x10 > [<ffffffff804c1748>] _cpu_down+0xa8/0x290 > [<ffffffff804c196b>] cpu_down+0x3b/0x60 > [<ffffffff804c2c68>] store_online+0x48/0xa0 > [<ffffffff803a46c4>] sysdev_store+0x24/0x30 > [<ffffffff802eebba>] sysfs_write_file+0xca/0x140 > [<ffffffff8029cb3b>] vfs_write+0xcb/0x170 > [<ffffffff8029ccd0>] sys_write+0x50/0x90 > [<ffffffff8020b92b>] system_call_after_swapgs+0x7b/0x80 > [<ffffffffffffffff>] 0xffffffffffffffff > > -> #0 (&cpu_hotplug.lock){--..}: > [<ffffffff80259913>] __lock_acquire+0xa53/0xe50 > [<ffffffff80259d6b>] lock_acquire+0x5b/0x80 > [<ffffffff804d12c4>] mutex_lock_nested+0x94/0x250 > [<ffffffff8025e024>] get_online_cpus+0x24/0x40 > [<ffffffff8022fee1>] sched_getaffinity+0x11/0x80 > [<ffffffff8026e6d9>] __synchronize_sched+0x19/0x90 > [<ffffffff8022ed46>] detach_destroy_domains+0x46/0x50 > [<ffffffff8022f6b9>] partition_sched_domains+0xf9/0x2b0 > [<ffffffff80268f9d>] rebuild_sched_domains+0x9d/0x3f0 > [<ffffffff8026a858>] cpuset_common_file_write+0x2b8/0x5c0 > [<ffffffff8026657c>] cgroup_file_write+0x7c/0x1a0 > [<ffffffff8029cb3b>] vfs_write+0xcb/0x170 > [<ffffffff8029ccd0>] sys_write+0x50/0x90 > [<ffffffff8020b92b>] system_call_after_swapgs+0x7b/0x80 > [<ffffffffffffffff>] 0xffffffffffffffff > > other info that might help us debug this: > > 2 locks held by bash/2779: > #0: (cgroup_mutex){--..}, at: [<ffffffff802653e2>] cgroup_lock+0x12/0x20 > #1: (sched_domains_mutex){--..}, at: [<ffffffff8022f5e9>] > partition_sched_domains+0x29/0x2b0 > > stack backtrace: > Pid: 2779, comm: bash Not tainted 2.6.26-rc8 #4 > > Call Trace: > [<ffffffff80258c0c>] print_circular_bug_tail+0x8c/0x90 > [<ffffffff802589c4>] ? print_circular_bug_entry+0x54/0x60 > [<ffffffff80259913>] __lock_acquire+0xa53/0xe50 > [<ffffffff8025e024>] ? get_online_cpus+0x24/0x40 > [<ffffffff80259d6b>] lock_acquire+0x5b/0x80 > [<ffffffff8025e024>] ? get_online_cpus+0x24/0x40 > [<ffffffff804d12c4>] mutex_lock_nested+0x94/0x250 > [<ffffffff8025867d>] ? mark_held_locks+0x4d/0x90 > [<ffffffff8025e024>] get_online_cpus+0x24/0x40 > [<ffffffff8022fee1>] sched_getaffinity+0x11/0x80 > [<ffffffff8026e6d9>] __synchronize_sched+0x19/0x90 > [<ffffffff8022ed46>] detach_destroy_domains+0x46/0x50 > [<ffffffff8022f6b9>] partition_sched_domains+0xf9/0x2b0 > [<ffffffff80258801>] ? trace_hardirqs_on+0xc1/0xe0 > [<ffffffff80268f9d>] rebuild_sched_domains+0x9d/0x3f0 > [<ffffffff8026a858>] cpuset_common_file_write+0x2b8/0x5c0 > [<ffffffff80268c00>] ? cpuset_test_cpumask+0x0/0x20 > [<ffffffff80269f20>] ? cpuset_change_cpumask+0x0/0x20 > [<ffffffff80265260>] ? started_after+0x0/0x50 > [<ffffffff8026657c>] cgroup_file_write+0x7c/0x1a0 > [<ffffffff8029cb3b>] vfs_write+0xcb/0x170 > [<ffffffff8029ccd0>] sys_write+0x50/0x90 > [<ffffffff8020b92b>] system_call_after_swapgs+0x7b/0x80 > > CPU3 attaching NULL sched-domain. > > > >
| |