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* 2.6.33.3: possible recursive locking detected
@ 2010-05-04  7:03 CaT
  2010-05-04  8:37 ` Avi Kivity
  0 siblings, 1 reply; 8+ messages in thread
From: CaT @ 2010-05-04  7:03 UTC (permalink / raw)
  To: lkml, avi, mtosatti, kvm

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. 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.

-- 
  "A search of his car uncovered pornography, a homemade sex aid, women's 
  stockings and a Jack Russell terrier."
    - http://www.news.com.au/story/0%2C27574%2C24675808-421%2C00.html

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2010-05-12 19:50 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-05-04  7:03 2.6.33.3: possible recursive locking detected CaT
2010-05-04  8:37 ` Avi Kivity
2010-05-05  2:32   ` Yong Zhang
2010-05-05  2:52     ` Américo Wang
2010-05-11 11:33       ` CaT
2010-05-11 15:03         ` Greg KH
2010-05-12  4:34           ` Américo Wang
2010-05-12 19:46             ` Greg KH

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