From: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
To: Viresh Kumar <viresh.kumar@linaro.org>, Juri Lelli <juri.lelli@arm.com>
Cc: Rafael Wysocki <rjw@rjwysocki.net>,
linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org,
skannan@codeaurora.org, peterz@infradead.org,
mturquette@baylibre.com, steve.muckle@linaro.org,
vincent.guittot@linaro.org, morten.rasmussen@arm.com,
dietmar.eggemann@arm.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2 0/7] cpufreq: governors: Fix ABBA lockups
Date: Fri, 05 Feb 2016 02:20:56 +0530 [thread overview]
Message-ID: <56B3B9B0.4010401@linux.vnet.ibm.com> (raw)
In-Reply-To: <20160204121727.GH3469@vireshk>
Hi,
>
> FWIW, Juri has reported on IRC that the above diff fixed the lockdep
> he reported yesterday and all the 7 patches are working fine on his
> test machine, Juno.
>
I could see the previous lockdep warnings on pm/next and on top of patch[4].
On Patch[5-7] I see the below lockdep trace on running './runme' on a Power8 box.
[ 710.332841] ======================================================
[ 710.332911] [ INFO: possible circular locking dependency detected ]
[ 710.332969] 4.5.0-rc2-sgb+ #104 Not tainted
[ 710.333004] -------------------------------------------------------
[ 710.333060] runme.sh/2476 is trying to acquire lock:
[ 710.333107] (s_active#91){++++.+}, at: [<c000000000407db8>]
kernfs_remove+0x48/0x70
[ 710.333215]
but task is already holding lock:
[ 710.333272] (od_dbs_cdata.mutex){+.+.+.}, at: [<c000000000ad7434>]
cpufreq_governor_dbs+0x64/0x7e0
[ 710.333388]
which lock already depends on the new lock.
[ 710.333456]
the existing dependency chain (in reverse order) is:
[ 710.333523]
-> #2 (od_dbs_cdata.mutex){+.+.+.}:
[ 710.333604] [<c000000000d48450>] mutex_lock_nested+0x90/0x590
[ 710.333673] [<c000000000ad5698>] update_sampling_rate+0x88/0x1c0
[ 710.333741] [<c000000000ad5830>] store_sampling_rate+0x60/0xa0
[ 710.333809] [<c000000000ad6990>] governor_store+0x80/0xc0
[ 710.333865] [<c00000000040a8a4>] sysfs_kf_write+0x94/0xc0
[ 710.333923] [<c0000000004094a8>] kernfs_fop_write+0x188/0x1f0
[ 710.333991] [<c000000000347b8c>] __vfs_write+0x6c/0x180
[ 710.334049] [<c0000000003490a0>] vfs_write+0xc0/0x200
[ 710.334107] [<c00000000034a3cc>] SyS_write+0x6c/0x110
[ 710.334163] [<c00000000000926c>] system_call+0x38/0xd0
[ 710.334222]
-> #1 (&dbs_data->mutex){+.+...}:
[ 710.334290] [<c000000000d48450>] mutex_lock_nested+0x90/0x590
[ 710.334358] [<c000000000ad6960>] governor_store+0x50/0xc0
[ 710.334415] [<c00000000040a8a4>] sysfs_kf_write+0x94/0xc0
[ 710.334471] [<c0000000004094a8>] kernfs_fop_write+0x188/0x1f0
[ 710.334539] [<c000000000347b8c>] __vfs_write+0x6c/0x180
[ 710.334596] [<c0000000003490a0>] vfs_write+0xc0/0x200
[ 710.334653] [<c00000000034a3cc>] SyS_write+0x6c/0x110
[ 710.334710] [<c00000000000926c>] system_call+0x38/0xd0
[ 710.334767]
-> #0 (s_active#91){++++.+}:
[ 710.334847] [<c00000000015f318>] lock_acquire+0xd8/0x1a0
[ 710.334905] [<c0000000004065f4>] __kernfs_remove+0x344/0x410
[ 710.334973] [<c000000000407db8>] kernfs_remove+0x48/0x70
[ 710.335030] [<c00000000040b868>] sysfs_remove_dir+0x78/0xd0
[ 710.335098] [<c0000000005eccec>] kobject_del+0x2c/0x80
[ 710.335156] [<c0000000005ec9e8>] kobject_release+0xa8/0x250
[ 710.335224] [<c000000000ad7ac8>] cpufreq_governor_dbs+0x6f8/0x7e0
[ 710.335292] [<c000000000ad4a7c>] od_cpufreq_governor_dbs+0x3c/0x60
[ 710.335361] [<c000000000acf7c4>] __cpufreq_governor+0x164/0x300
[ 710.335429] [<c000000000ad0600>] cpufreq_set_policy+0x3b0/0x450
[ 710.335497] [<c000000000ad117c>] store_scaling_governor+0x8c/0xf0
[ 710.335565] [<c000000000aced34>] store+0xb4/0x110
[ 710.335622] [<c00000000040a8a4>] sysfs_kf_write+0x94/0xc0
[ 710.335679] [<c0000000004094a8>] kernfs_fop_write+0x188/0x1f0
[ 710.335747] [<c000000000347b8c>] __vfs_write+0x6c/0x180
[ 710.335803] [<c0000000003490a0>] vfs_write+0xc0/0x200
[ 710.335861] [<c00000000034a3cc>] SyS_write+0x6c/0x110
[ 710.335918] [<c00000000000926c>] system_call+0x38/0xd0
[ 710.335993]
other info that might help us debug this:
[ 710.336130] Chain exists of:
s_active#91 --> &dbs_data->mutex --> od_dbs_cdata.mutex
[ 710.336376] Possible unsafe locking scenario:
[ 710.336488] CPU0 CPU1
[ 710.336577] ---- ----
[ 710.336666] lock(od_dbs_cdata.mutex);
[ 710.336778] lock(&dbs_data->mutex);
[ 710.336911] lock(od_dbs_cdata.mutex);
[ 710.337064] lock(s_active#91);
[ 710.337176]
*** DEADLOCK ***
[ 710.337289] 6 locks held by runme.sh/2476:
[ 710.337355] #0: (sb_writers#6){.+.+.+}, at: [<c00000000034cf10>]
__sb_start_write+0x120/0x150
[ 710.337600] #1: (&of->mutex){+.+.+.}, at: [<c00000000040939c>]
kernfs_fop_write+0x7c/0x1f0
[ 710.337824] #2: (s_active#82){.+.+.+}, at: [<c0000000004093a8>]
kernfs_fop_write+0x88/0x1f0
[ 710.338070] #3: (cpu_hotplug.lock){++++++}, at: [<c0000000000e06d8>]
get_online_cpus+0x48/0xc0
[ 710.338276] #4: (&policy->rwsem){+++++.}, at: [<c000000000aced04>]
store+0x84/0x110
[ 710.338476] #5: (od_dbs_cdata.mutex){+.+.+.}, at: [<c000000000ad7434>]
cpufreq_governor_dbs+0x64/0x7e0
[ 710.338722]
stack backtrace:
[ 710.338813] CPU: 0 PID: 2476 Comm: runme.sh Not tainted 4.5.0-rc2-sgb+ #104
[ 710.338929] Call Trace:
[ 710.338978] [c000005fd40eaec0] [c000000000d563d0] dump_stack+0x90/0xbc
(unreliable)
[ 710.339138] [c000005fd40eaef0] [c00000000015884c] print_circular_bug+0x28c/0x3e0
[ 710.339295] [c000005fd40eaf90] [c00000000015ed88] __lock_acquire+0x2278/0x22d0
[ 710.339455] [c000005fd40eb120] [c00000000015f318] lock_acquire+0xd8/0x1a0
[ 710.339589] [c000005fd40eb1e0] [c0000000004065f4] __kernfs_remove+0x344/0x410
[ 710.339724] [c000005fd40eb2e0] [c000000000407db8] kernfs_remove+0x48/0x70
[ 710.339859] [c000005fd40eb310] [c00000000040b868] sysfs_remove_dir+0x78/0xd0
[ 710.339993] [c000005fd40eb350] [c0000000005eccec] kobject_del+0x2c/0x80
[ 710.340128] [c000005fd40eb380] [c0000000005ec9e8] kobject_release+0xa8/0x250
[ 710.340265] [c000005fd40eb410] [c000000000ad7ac8]
cpufreq_governor_dbs+0x6f8/0x7e0
[ 710.340423] [c000005fd40eb4c0] [c000000000ad4a7c]
od_cpufreq_governor_dbs+0x3c/0x60
[ 710.340561] [c000005fd40eb500] [c000000000acf7c4] __cpufreq_governor+0x164/0x300
[ 710.340639] [c000005fd40eb580] [c000000000ad0600] cpufreq_set_policy+0x3b0/0x450
[ 710.340719] [c000005fd40eb610] [c000000000ad117c]
store_scaling_governor+0x8c/0xf0
[ 710.340797] [c000005fd40ebc10] [c000000000aced34] store+0xb4/0x110
[ 710.340866] [c000005fd40ebc60] [c00000000040a8a4] sysfs_kf_write+0x94/0xc0
[ 710.340934] [c000005fd40ebca0] [c0000000004094a8] kernfs_fop_write+0x188/0x1f0
[ 710.341013] [c000005fd40ebcf0] [c000000000347b8c] __vfs_write+0x6c/0x180
[ 710.341081] [c000005fd40ebd90] [c0000000003490a0] vfs_write+0xc0/0x200
[ 710.341151] [c000005fd40ebde0] [c00000000034a3cc] SyS_write+0x6c/0x110
[ 710.341219] [c000005fd40ebe30] [c00000000000926c] system_call+0x38/0xd0
Thanks and Regards,
Shilpa
next prev parent reply other threads:[~2016-02-04 20:52 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-03 14:02 [PATCH V2 0/7] cpufreq: governors: Fix ABBA lockups Viresh Kumar
2016-02-03 14:02 ` [PATCH V2 1/7] cpufreq: governor: Treat min_sampling_rate as a governor-specific tunable Viresh Kumar
2016-02-05 2:31 ` Rafael J. Wysocki
2016-02-05 2:47 ` Viresh Kumar
2016-02-03 14:02 ` [PATCH V2 2/7] cpufreq: governor: New sysfs show/store callbacks for governor tunables Viresh Kumar
2016-02-03 16:17 ` Viresh Kumar
2016-02-03 14:02 ` [PATCH V2 3/7] cpufreq: governor: Drop unused macros for creating governor tunable attributes Viresh Kumar
2016-02-03 14:02 ` [PATCH V2 4/7] Revert "cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT" Viresh Kumar
2016-02-03 14:02 ` [PATCH V2 5/7] cpufreq: Merge cpufreq_offline_prepare/finish routines Viresh Kumar
2016-02-03 20:21 ` Saravana Kannan
2016-02-04 1:49 ` Viresh Kumar
2016-02-03 14:02 ` [PATCH V2 6/7] cpufreq: Call __cpufreq_governor() with policy->rwsem held Viresh Kumar
2016-02-03 14:02 ` [PATCH V2 7/7] cpufreq: Remove cpufreq_governor_lock Viresh Kumar
2016-02-04 6:43 ` Viresh Kumar
2016-02-03 15:54 ` [PATCH V2 0/7] cpufreq: governors: Fix ABBA lockups Juri Lelli
2016-02-03 16:10 ` Viresh Kumar
2016-02-03 17:20 ` Juri Lelli
2016-02-03 17:20 ` Rafael J. Wysocki
2016-02-03 23:31 ` Shilpa Bhat
2016-02-03 23:50 ` Rafael J. Wysocki
2016-02-04 5:51 ` Viresh Kumar
2016-02-04 11:09 ` Viresh Kumar
2016-02-04 17:43 ` Saravana Kannan
2016-02-04 17:44 ` Saravana Kannan
2016-02-04 18:18 ` Rafael J. Wysocki
2016-02-05 2:44 ` Viresh Kumar
2016-02-05 3:54 ` Rafael J. Wysocki
2016-02-05 9:49 ` Viresh Kumar
2016-02-08 2:20 ` Rafael J. Wysocki
2016-02-06 2:22 ` Saravana Kannan
2016-02-08 2:28 ` Rafael J. Wysocki
2016-02-09 21:02 ` Saravana Kannan
2016-02-04 6:24 ` Viresh Kumar
2016-02-04 12:17 ` Viresh Kumar
2016-02-04 20:50 ` Shilpasri G Bhat [this message]
2016-02-05 2:49 ` Viresh Kumar
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