Messages in this thread | | | Subject | Re: [patch] Reorganize the cpufreq cpu hotplug locking to not be totally bizare | From | Sanjoy Mahajan <> | Date | 26 Jul 2006 23:35:50 +0100 |
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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. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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