From: Sanjoy Mahajan <sanjoy@mrao.cam.ac.uk>
To: Andrew Morton <akpm@osdl.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>,
vatsa@in.ibm.com, torvalds@osdl.org, davej@redhat.com,
mingo@elte.hu, 76306.1226@compuserve.com, ashok.raj@intel.com,
linux-kernel@vger.kernel.org
Subject: Re: [patch] Reorganize the cpufreq cpu hotplug locking to not be totally bizare
Date: 26 Jul 2006 23:35:50 +0100 [thread overview]
Message-ID: <r6ejw8vvsp.fsf@skye.ra.phy.cam.ac.uk> (raw)
In-Reply-To: <20060726143357.2f0787e7.akpm@osdl.org>
From: Andrew Morton <akpm@osdl.org>
> We should delete lock_cpu_hotplug() and start again.
Here is another example of possible lock_cpu_hotplug() problems. Is
it worth tracking down, or should I just ignore the messages until a
proper solution is figured out? The only problem is that it means S3
suspend doesn't work.
The hardware is a Thinkpad T60, T2400 dual-core, compiled with SMP and
PREEMPT, hotpluggable CPUs, and it has a SATA drive. Kernel is
2.6.18-rc1. Suspend (UP) worked with 2.6.15-25-386 from Ubuntu using
the same sleep.sh script. The messages below, including the large
lockdep backtrace, occur after running sleep.sh (run by Fn-F4):
[ 546.652000] Stopping tasks: ====================================================================================
[ 566.848000] stopping tasks timed out after 20 seconds (8 tasks remaining):
[ 566.848000] rt-test-0
[ 566.848000] rt-test-1
[ 566.848000] rt-test-2
[ 566.848000] rt-test-3
[ 566.848000] rt-test-4
[ 566.848000] rt-test-5
[ 566.848000] rt-test-6
[ 566.848000] rt-test-7
The lockdep code also reported problems:
[ 538.292000] ACPI: PCI interrupt for device 0000:02:00.0 disabled
[ 546.144000] Freezing cpus ...
[ 546.172000]
[ 546.172000] =======================================================
[ 546.172000] [ INFO: possible circular locking dependency detected ]
[ 546.172000] -------------------------------------------------------
[ 546.172000] sleep.sh/15184 is trying to acquire lock:
[ 546.172000] (&policy->lock){--..}, at: [<c0310645>] mutex_lock+0x25/0x30
[ 546.172000]
[ 546.172000] but task is already holding lock:
[ 546.172000] ((cpu_chain).rwsem){----}, at: [<c0133267>] blocking_notifier_call_chain+0x17/0x40
[ 546.172000]
[ 546.172000] which lock already depends on the new lock.
[ 546.172000]
[ 546.172000]
[ 546.172000] the existing dependency chain (in reverse order) is:
[ 546.172000]
[ 546.172000] -> #2 ((cpu_chain).rwsem){----}:
[ 546.172000] [<c0142479>] lock_acquire+0x69/0x90
[ 546.172000] [<c013e08f>] down_read+0x4f/0x60
[ 546.172000] [<c0133267>] blocking_notifier_call_chain+0x17/0x40
[ 546.172000] [<c0147496>] cpu_up+0x76/0x110
[ 546.172000] [<c01005e5>] init+0x295/0x370
[ 546.172000] [<c0101005>] kernel_thread_helper+0x5/0x10
[ 546.176000]
[ 546.176000] -> #1 (cpucontrol){--..}:
[ 546.176000] [<c0142479>] lock_acquire+0x69/0x90
[ 546.176000] [<c03103de>] __mutex_lock_slowpath+0x7e/0x2c0
[ 546.176000] [<c0310645>] mutex_lock+0x25/0x30
[ 546.176000] [<c01473c9>] __lock_cpu_hotplug+0x29/0x70
[ 546.176000] [<c014753a>] lock_cpu_hotplug+0xa/0x10
[ 546.176000] [<c02ae6cf>] __cpufreq_driver_target+0xf/0x60
[ 546.176000] [<c02b0218>] cpufreq_governor_performance+0x38/0x40
[ 546.176000] [<c02aee1c>] __cpufreq_governor+0x9c/0x1c0
[ 546.176000] [<c02af1d3>] __cpufreq_set_policy+0x103/0x150
[ 546.180000] [<c02af52e>] cpufreq_set_policy+0x4e/0x90
[ 546.180000] [<c02af871>] cpufreq_add_dev+0x301/0x5a0
[ 546.180000] [<c026685b>] sysdev_driver_register+0x7b/0xc0
[ 546.180000] [<c02af018>] cpufreq_register_driver+0x78/0x130
[ 546.180000] [<f899f04b>] 0xf899f04b
[ 546.180000] [<c014ae93>] sys_init_module+0xa3/0x210
[ 546.180000] [<c010339d>] sysenter_past_esp+0x56/0x8d
[ 546.180000]
[ 546.180000] -> #0 (&policy->lock){--..}:
[ 546.180000] [<c0142479>] lock_acquire+0x69/0x90
[ 546.180000] [<c03103de>] __mutex_lock_slowpath+0x7e/0x2c0
[ 546.184000] [<c0310645>] mutex_lock+0x25/0x30
[ 546.184000] [<c02aecf2>] cpufreq_driver_target+0x32/0x70
[ 546.184000] [<c02afd54>] cpufreq_cpu_callback+0x64/0xb0
[ 546.184000] [<c01330e0>] notifier_call_chain+0x30/0x50
[ 546.184000] [<c0133275>] blocking_notifier_call_chain+0x25/0x40
[ 546.184000] [<c01475ca>] cpu_down+0x8a/0x2a0
[ 546.184000] [<c014cb51>] disable_nonboot_cpus+0x51/0xd0
[ 546.184000] [<c014bef7>] enter_state+0x67/0x1b0
[ 546.184000] [<c014c0df>] state_store+0x9f/0xb0
[ 546.184000] [<c01afb4e>] subsys_attr_store+0x2e/0x30
[ 546.188000] [<c01b0345>] sysfs_write_file+0xb5/0x100
[ 546.188000] [<c0171c67>] vfs_write+0xa7/0x190
[ 546.188000] [<c0172697>] sys_write+0x47/0x70
[ 546.188000] [<c010339d>] sysenter_past_esp+0x56/0x8d
[ 546.188000]
[ 546.188000] other info that might help us debug this:
[ 546.188000]
[ 546.188000] 2 locks held by sleep.sh/15184:
[ 546.188000] #0: (cpucontrol){--..}, at: [<c0310355>] mutex_lock_interruptible+0x25/0x30
[ 546.188000] #1: ((cpu_chain).rwsem){----}, at: [<c0133267>] blocking_notifier_call_chain+0x17/0x40
[ 546.188000]
[ 546.188000] stack backtrace:
[ 546.188000] [<c0105c5b>] show_trace+0x1b/0x20
[ 546.188000] [<c0105c84>] dump_stack+0x24/0x30
[ 546.188000] [<c013fe41>] print_circular_bug_tail+0x61/0x70
[ 546.188000] [<c0141b77>] __lock_acquire+0x867/0xde0
[ 546.188000] [<c0142479>] lock_acquire+0x69/0x90
[ 546.188000] [<c03103de>] __mutex_lock_slowpath+0x7e/0x2c0
[ 546.188000] [<c0310645>] mutex_lock+0x25/0x30
[ 546.188000] [<c02aecf2>] cpufreq_driver_target+0x32/0x70
[ 546.188000] [<c02afd54>] cpufreq_cpu_callback+0x64/0xb0
[ 546.188000] [<c01330e0>] notifier_call_chain+0x30/0x50
[ 546.192000] [<c0133275>] blocking_notifier_call_chain+0x25/0x40
[ 546.192000] [<c01475ca>] cpu_down+0x8a/0x2a0
[ 546.192000] [<c014cb51>] disable_nonboot_cpus+0x51/0xd0
[ 546.192000] [<c014bef7>] enter_state+0x67/0x1b0
[ 546.192000] [<c014c0df>] state_store+0x9f/0xb0
[ 546.192000] [<c01afb4e>] subsys_attr_store+0x2e/0x30
[ 546.192000] [<c01b0345>] sysfs_write_file+0xb5/0x100
[ 546.192000] [<c0171c67>] vfs_write+0xa7/0x190
[ 546.192000] [<c0172697>] sys_write+0x47/0x70
[ 546.192000] [<c010339d>] sysenter_past_esp+0x56/0x8d
[ 546.204000] Breaking affinity for irq 0
[ 546.308000] CPU 1 is now offline
[ 546.308000] lockdep: not fixing up alternatives.
[ 546.652000] CPU1 is down
[ 546.652000] Stopping tasks: ====================================================================================
[ 566.848000] stopping tasks timed out after 20 seconds (8 tasks remaining):
[ 566.848000] rt-test-0
[ 566.848000] rt-test-1
[ 566.848000] rt-test-2
[ 566.848000] rt-test-3
[ 566.848000] rt-test-4
[ 566.848000] rt-test-5
[ 566.848000] rt-test-6
[ 566.848000] rt-test-7
[ 566.848000] Restarting tasks...<6> Strange, rt-test-0 not stopped
[ 566.848000] Strange, rt-test-1 not stopped
[ 566.848000] Strange, rt-test-2 not stopped
[ 566.848000] Strange, rt-test-3 not stopped
[ 566.848000] Strange, rt-test-4 not stopped
[ 566.848000] Strange, rt-test-5 not stopped
[ 566.848000] Strange, rt-test-6 not stopped
[ 566.848000] Strange, rt-test-7 not stopped
[ 568.112000] done
[ 568.112000] Thawing cpus ...
[ 568.464000] lockdep: not fixing up alternatives.
[ 568.464000] Booting processor 1/1 eip 3000
[ 568.472000] Initializing CPU#1
etc.
next prev parent reply other threads:[~2006-07-26 22:36 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-25 0:21 remove cpu hotplug bustification in cpufreq Chuck Ebbert
2006-07-25 0:59 ` Linus Torvalds
2006-07-25 15:06 ` Erik Mouw
2006-07-25 18:54 ` Ingo Molnar
2006-07-25 19:30 ` Arjan van de Ven
2006-07-25 20:57 ` Linus Torvalds
2006-07-26 13:40 ` [patch] Reorganize the cpufreq cpu hotplug locking to not be totally bizare Arjan van de Ven
2006-07-26 15:51 ` Dave Jones
2006-07-26 17:09 ` Linus Torvalds
2006-07-26 19:42 ` Arjan van de Ven
2006-07-26 20:22 ` Linus Torvalds
2006-07-26 20:58 ` Srivatsa Vaddagiri
2006-07-26 21:29 ` Linus Torvalds
2006-07-26 21:38 ` Arjan van de Ven
2006-07-27 1:40 ` Ingo Molnar
2006-07-27 17:38 ` Ashok Raj
2006-07-29 13:45 ` Ingo Molnar
2006-07-26 21:15 ` Ashok Raj
2006-07-27 19:29 ` Langsdorf, Mark
2006-07-28 13:50 ` Andi Kleen
2006-07-28 17:09 ` Langsdorf, Mark
2006-07-26 20:42 ` Srivatsa Vaddagiri
2006-07-26 21:03 ` Arjan van de Ven
2006-07-26 21:21 ` Srivatsa Vaddagiri
2006-07-26 21:33 ` Rafael J. Wysocki
2006-07-26 21:33 ` Andrew Morton
2006-07-26 22:35 ` Sanjoy Mahajan [this message]
2006-07-26 22:44 ` Arjan van de Ven
2006-07-25 20:46 ` remove cpu hotplug bustification in cpufreq Dave Jones
2006-07-25 20:59 ` Linus Torvalds
2006-07-26 17:12 ` Russell King
2006-07-26 17:53 ` Dave Jones
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