http://bugzilla.kernel.org/show_bug.cgi?id=13493 Summary: cpufreq: INFO: possible circular locking dependency detected Product: Power Management Version: 2.5 Kernel Version: 2.6.30-rc8 Platform: All OS/Version: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: cpufreq AssignedTo: cpufreq@xxxxxxxxxxxxxxx ReportedBy: nm127@xxxxxxxxxxx Regression: No Created an attachment (id=21832) --> (http://bugzilla.kernel.org/attachment.cgi?id=21832) dmesg 2.6.30-rc8 Trying to set "powersave" governor on EeePC 901 causes possible circular locking dependency message in dmesg. Steps to reproduce: 1. boot the system 2. modprobe -k acpi-cpufreq 3. modprobe -k cpufreq-ondemand 4. echo powersave >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor Actual result: [ 77.802623] ======================================================= [ 77.802807] [ INFO: possible circular locking dependency detected ] [ 77.802913] 2.6.30-rc8 #1 [ 77.802999] ------------------------------------------------------- [ 77.803102] bash/2317 is trying to acquire lock: [ 77.803197] (&(&dbs_info->work)->work){+.+...}, at: [<c013abd8>] __cancel_work_timer+0x8f/0x190 [ 77.803502] [ 77.803506] but task is already holding lock: [ 77.803673] (dbs_mutex){+.+.+.}, at: [<f94dea44>] cpufreq_governor_dbs+0x296/0x322 [cpufreq_ondemand] [ 77.803981] [ 77.803985] which lock already depends on the new lock. [ 77.803990] [ 77.804231] [ 77.804235] the existing dependency chain (in reverse order) is: [ 77.804408] [ 77.804412] -> #2 (dbs_mutex){+.+.+.}: [ 77.804733] [<c014d3b5>] __lock_acquire+0xf85/0x128d [ 77.804890] [<c014d770>] lock_acquire+0xb3/0xd6 [ 77.804928] [<c034c432>] mutex_lock_nested+0x45/0x2b0 [ 77.804928] [<f94de828>] cpufreq_governor_dbs+0x7a/0x322 [cpufreq_ondemand] [ 77.804928] [<c02cabfd>] __cpufreq_governor+0x9d/0xd3 [ 77.804928] [<c02cae43>] __cpufreq_set_policy+0xe7/0x11f [ 77.804928] [<c02cb7bc>] store_scaling_governor+0x197/0x1bf [ 77.804928] [<c02cc19e>] store+0x48/0x61 [ 77.804928] [<c01de7f8>] sysfs_write_file+0xb9/0xe4 [ 77.804928] [<c01a1954>] vfs_write+0x8a/0x12e [ 77.804928] [<c01a1a91>] sys_write+0x3b/0x60 [ 77.804928] [<c01031a4>] sysenter_do_call+0x12/0x38 [ 77.804928] [<ffffffff>] 0xffffffff [ 77.804928] [ 77.804928] -> #1 (&per_cpu(cpu_policy_rwsem, cpu)){+++++.}: [ 77.804928] [<c014d3b5>] __lock_acquire+0xf85/0x128d [ 77.804928] [<c014d770>] lock_acquire+0xb3/0xd6 [ 77.804928] [<c034ccae>] down_write+0x2a/0x46 [ 77.804928] [<c02cbb7d>] lock_policy_rwsem_write+0x33/0x5b [ 77.804928] [<f94de527>] do_dbs_timer+0x4b/0x2d2 [cpufreq_ondemand] [ 77.804928] [<c013a50f>] worker_thread+0x1ad/0x28a [ 77.804928] [<c013d8ae>] kthread+0x45/0x6b [ 77.804928] [<c0103d63>] kernel_thread_helper+0x7/0x10 [ 77.804928] [<ffffffff>] 0xffffffff [ 77.804928] [ 77.804928] -> #0 (&(&dbs_info->work)->work){+.+...}: [ 77.804928] [<c014d145>] __lock_acquire+0xd15/0x128d [ 77.804928] [<c014d770>] lock_acquire+0xb3/0xd6 [ 77.804928] [<c013abfe>] __cancel_work_timer+0xb5/0x190 [ 77.804928] [<c013ace4>] cancel_delayed_work_sync+0xb/0xd [ 77.804928] [<f94dea58>] cpufreq_governor_dbs+0x2aa/0x322 [cpufreq_ondemand] [ 77.804928] [<c02cabfd>] __cpufreq_governor+0x9d/0xd3 [ 77.804928] [<c02cae2d>] __cpufreq_set_policy+0xd1/0x11f [ 77.804928] [<c02cb7bc>] store_scaling_governor+0x197/0x1bf [ 77.804928] [<c02cc19e>] store+0x48/0x61 [ 77.804928] [<c01de7f8>] sysfs_write_file+0xb9/0xe4 [ 77.804928] [<c01a1954>] vfs_write+0x8a/0x12e [ 77.804928] [<c01a1a91>] sys_write+0x3b/0x60 [ 77.804928] [<c01031a4>] sysenter_do_call+0x12/0x38 [ 77.804928] [<ffffffff>] 0xffffffff [ 77.804928] [ 77.804928] other info that might help us debug this: [ 77.804928] [ 77.804928] 3 locks held by bash/2317: [ 77.804928] #0: (&buffer->mutex){+.+.+.}, at: [<c01de764>] sysfs_write_file+0x25/0xe4 [ 77.804928] #1: (&per_cpu(cpu_policy_rwsem, cpu)){+++++.}, at: [<c02cbb7d>] lock_policy_rwsem_write+0x33/0x5b [ 77.804928] #2: (dbs_mutex){+.+.+.}, at: [<f94dea44>] cpufreq_governor_dbs+0x296/0x322 [cpufreq_ondemand] [ 77.804928] [ 77.804928] stack backtrace: [ 77.804928] Pid: 2317, comm: bash Not tainted 2.6.30-rc8 #1 [ 77.804928] Call Trace: [ 77.804928] [<c034ac15>] ? printk+0xf/0x12 [ 77.804928] [<c014c061>] print_circular_bug_tail+0xa3/0xae [ 77.804928] [<c014d145>] __lock_acquire+0xd15/0x128d [ 77.804928] [<c014d770>] lock_acquire+0xb3/0xd6 [ 77.804928] [<c013abd8>] ? __cancel_work_timer+0x8f/0x190 [ 77.804928] [<c013abfe>] __cancel_work_timer+0xb5/0x190 [ 77.804928] [<c013abd8>] ? __cancel_work_timer+0x8f/0x190 [ 77.804928] [<c034c657>] ? mutex_lock_nested+0x26a/0x2b0 [ 77.804928] [<c014b985>] ? trace_hardirqs_on_caller+0x103/0x124 [ 77.804928] [<c034c683>] ? mutex_lock_nested+0x296/0x2b0 [ 77.804928] [<c013ace4>] cancel_delayed_work_sync+0xb/0xd [ 77.804928] [<f94dea58>] cpufreq_governor_dbs+0x2aa/0x322 [cpufreq_ondemand] [ 77.804928] [<c014180c>] ? __blocking_notifier_call_chain+0x40/0x4c [ 77.804928] [<c02cabfd>] __cpufreq_governor+0x9d/0xd3 [ 77.804928] [<c02cae2d>] __cpufreq_set_policy+0xd1/0x11f [ 77.804928] [<c02cb7bc>] store_scaling_governor+0x197/0x1bf [ 77.804928] [<c02cc28d>] ? handle_update+0x0/0xd [ 77.804928] [<c02cbb7d>] ? lock_policy_rwsem_write+0x33/0x5b [ 77.804928] [<c02cb625>] ? store_scaling_governor+0x0/0x1bf [ 77.804928] [<c02cc19e>] store+0x48/0x61 [ 77.804928] [<c01de7f8>] sysfs_write_file+0xb9/0xe4 [ 77.804928] [<c01de73f>] ? sysfs_write_file+0x0/0xe4 [ 77.804928] [<c01a1954>] vfs_write+0x8a/0x12e [ 77.804928] [<c01a1a91>] sys_write+0x3b/0x60 [ 77.804928] [<c01031a4>] sysenter_do_call+0x12/0x38 -- Configure bugmail: http://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
