linux-kernel - Re: 2.6.33.3: possible recursive locking detected

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Message-ID: <4BDFDCD1.70202@redhat.com>
Date:	Tue, 04 May 2010 11:37:37 +0300
From:	Avi Kivity <avi@...hat.com>
To:	CaT <cat@....com.au>
CC:	lkml@....com.au, mtosatti@...hat.com, kvm@...r.kernel.org,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: 2.6.33.3: possible recursive locking detected

On 05/04/2010 10:03 AM, CaT wrote:
> I'm currently running 2.6.33.3 in a KVM instance emulating a core2duo
> on 1 cpu with virtio HDs running on top of a core2duo host running 2.6.33.3.
> qemu-kvm version 0.12.3.

Doesn't appear to be related to kvm.  Copying lkml.

> When doing:
>
> echo noop>/sys/block/vdd/queue/scheduler
>
> I got:
>
> [ 1424.438241] =============================================
> [ 1424.439588] [ INFO: possible recursive locking detected ]
> [ 1424.440368] 2.6.33.3-moocow.20100429-142641 #2
> [ 1424.440960] ---------------------------------------------
> [ 1424.440960] bash/2186 is trying to acquire lock:
> [ 1424.440960]  (s_active){++++.+}, at: [<ffffffff811046b8>] sysfs_remove_dir+0x75/0x88
> [ 1424.440960]
> [ 1424.440960] but task is already holding lock:
> [ 1424.440960]  (s_active){++++.+}, at: [<ffffffff81104849>] sysfs_get_active_two+0x1f/0x46
> [ 1424.440960]
> [ 1424.440960] other info that might help us debug this:
> [ 1424.440960] 4 locks held by bash/2186:
> [ 1424.440960]  #0:  (&buffer->mutex){+.+.+.}, at: [<ffffffff8110317f>] sysfs_write_file+0x39/0x126
> [ 1424.440960]  #1:  (s_active){++++.+}, at: [<ffffffff81104849>] sysfs_get_active_two+0x1f/0x46
> [ 1424.440960]  #2:  (s_active){++++.+}, at: [<ffffffff81104856>] sysfs_get_active_two+0x2c/0x46
> [ 1424.440960]  #3:  (&q->sysfs_lock){+.+.+.}, at: [<ffffffff8119c3f0>] queue_attr_store+0x44/0x85
> [ 1424.440960]
> [ 1424.440960] stack backtrace:
> [ 1424.440960] Pid: 2186, comm: bash Not tainted 2.6.33.3-moocow.20100429-142641 #2
> [ 1424.440960] Call Trace:
> [ 1424.440960]  [<ffffffff8105e775>] __lock_acquire+0xf9f/0x178e
> [ 1424.440960]  [<ffffffff8100d3ec>] ? save_stack_trace+0x2a/0x48
> [ 1424.440960]  [<ffffffff8105b46c>] ? lockdep_init_map+0x9f/0x52f
> [ 1424.440960]  [<ffffffff8105b46c>] ? lockdep_init_map+0x9f/0x52f
> [ 1424.440960]  [<ffffffff8105cb56>] ? trace_hardirqs_on+0xd/0xf
> [ 1424.440960]  [<ffffffff8105f02e>] lock_acquire+0xca/0xef
> [ 1424.440960]  [<ffffffff811046b8>] ? sysfs_remove_dir+0x75/0x88
> [ 1424.440960]  [<ffffffff8110458d>] sysfs_addrm_finish+0xc8/0x13a
> [ 1424.440960]  [<ffffffff811046b8>] ? sysfs_remove_dir+0x75/0x88
> [ 1424.440960]  [<ffffffff8105cb25>] ? trace_hardirqs_on_caller+0x110/0x134
> [ 1424.440960]  [<ffffffff811046b8>] sysfs_remove_dir+0x75/0x88
> [ 1424.440960]  [<ffffffff811ab312>] kobject_del+0x16/0x37
> [ 1424.440960]  [<ffffffff81195489>] elv_iosched_store+0x10a/0x214
> [ 1424.440960]  [<ffffffff8119c416>] queue_attr_store+0x6a/0x85
> [ 1424.440960]  [<ffffffff81103237>] sysfs_write_file+0xf1/0x126
> [ 1424.440960]  [<ffffffff810b747f>] vfs_write+0xae/0x14a
> [ 1424.440960]  [<ffffffff810b75df>] sys_write+0x47/0x6e
> [ 1424.440960]  [<ffffffff81002202>] system_call_fastpath+0x16/0x1b
>
> Original scheduler was cfq.
>
> Having rebooted and defaulted to noop I tried
>
> echo noop>/sys/block/vdd/queue/scheduler
>
> and got:
>
> [  311.294464] =============================================
> [  311.295820] [ INFO: possible recursive locking detected ]
> [  311.296603] 2.6.33.3-moocow.20100429-142641 #2
> [  311.296833] ---------------------------------------------
> [  311.296833] bash/2190 is trying to acquire lock:
> [  311.296833]  (s_active){++++.+}, at: [<ffffffff81104630>] remove_dir+0x31/0x39
> [  311.296833]
> [  311.296833] but task is already holding lock:
> [  311.296833]  (s_active){++++.+}, at: [<ffffffff81104849>] sysfs_get_active_two+0x1f/0x46
> [  311.296833]
> [  311.296833] other info that might help us debug this:
> [  311.296833] 4 locks held by bash/2190:
> [  311.296833]  #0:  (&buffer->mutex){+.+.+.}, at: [<ffffffff8110317f>] sysfs_write_file+0x39/0x126
> [  311.296833]  #1:  (s_active){++++.+}, at: [<ffffffff81104849>] sysfs_get_active_two+0x1f/0x46
> [  311.296833]  #2:  (s_active){++++.+}, at: [<ffffffff81104856>] sysfs_get_active_two+0x2c/0x46
> [  311.296833]  #3:  (&q->sysfs_lock){+.+.+.}, at: [<ffffffff8119c3f0>] queue_attr_store+0x44/0x85
> [  311.296833]
> [  311.296833] stack backtrace:
> [  311.296833] Pid: 2190, comm: bash Not tainted 2.6.33.3-moocow.20100429-142641 #2
> [  311.296833] Call Trace:
> [  311.296833]  [<ffffffff8105e775>] __lock_acquire+0xf9f/0x178e
> [  311.296833]  [<ffffffff8105b46c>] ? lockdep_init_map+0x9f/0x52f
> [  311.296833]  [<ffffffff8105b46c>] ? lockdep_init_map+0x9f/0x52f
> [  311.296833]  [<ffffffff8105cb56>] ? trace_hardirqs_on+0xd/0xf
> [  311.296833]  [<ffffffff8105f02e>] lock_acquire+0xca/0xef
> [  311.296833]  [<ffffffff81104630>] ? remove_dir+0x31/0x39
> [  311.296833]  [<ffffffff8110458d>] sysfs_addrm_finish+0xc8/0x13a
> [  311.296833]  [<ffffffff81104630>] ? remove_dir+0x31/0x39
> [  311.296833]  [<ffffffff8105cb25>] ? trace_hardirqs_on_caller+0x110/0x134
> [  311.296833]  [<ffffffff81104630>] remove_dir+0x31/0x39
> [  311.296833]  [<ffffffff811046c0>] sysfs_remove_dir+0x7d/0x88
> [  311.296833]  [<ffffffff811ab312>] kobject_del+0x16/0x37
> [  311.296833]  [<ffffffff81195489>] elv_iosched_store+0x10a/0x214
> [  311.296833]  [<ffffffff8119c416>] queue_attr_store+0x6a/0x85
> [  311.296833]  [<ffffffff81103237>] sysfs_write_file+0xf1/0x126
> [  311.296833]  [<ffffffff810b747f>] vfs_write+0xae/0x14a
> [  311.296833]  [<ffffffff810b75df>] sys_write+0x47/0x6e
> [  311.296833]  [<ffffffff81002202>] system_call_fastpath+0x16/0x1b
>
> Changing back to noop (or, in the initial case to cfq) did not
> reproduce the message.
>
> This does not happen when the elevator is explicitly set on bootup as
> part of the kernel's commandline. Compiled-in default is cfq.
>
>    


-- 
error compiling committee.c: too many arguments to function

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