* [PATCH] i2c_powermac: shut up lockdep warning
@ 2016-09-21 11:34 Denis Kirjanov
2016-09-26 11:00 ` Denis Kirjanov
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Denis Kirjanov @ 2016-09-21 11:34 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Michael Ellerman, Benjamin Herrenschmidt, Denis Kirjanov
That's unclear why lockdep shows the following warning but adding a
lockdep class to struct pmac_i2c_bus solves it
[ 20.507795] ======================================================
[ 20.507796] [ INFO: possible circular locking dependency detected ]
[ 20.507800] 4.8.0-rc7-00037-gd2ffb01 #21 Not tainted
[ 20.507801] -------------------------------------------------------
[ 20.507803] swapper/0/1 is trying to acquire lock:
[ 20.507818] (&bus->mutex){+.+.+.}, at: [<c000000000052830>] .pmac_i2c_open+0x30/0x100
[ 20.507819]
[ 20.507819] but task is already holding lock:
[ 20.507829] (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0
[ 20.507830]
[ 20.507830] which lock already depends on the new lock.
[ 20.507830]
[ 20.507832]
[ 20.507832] the existing dependency chain (in reverse order) is:
[ 20.507837]
[ 20.507837] -> #4 (&policy->rwsem){+.+.+.}:
[ 20.507844] [<c00000000082385c>] .down_write+0x6c/0x110
[ 20.507849] [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0
[ 20.507855] [<c0000000004d76d8>] .subsys_interface_register+0xb8/0x110
[ 20.507860] [<c000000000689bb0>] .cpufreq_register_driver+0x1d0/0x250
[ 20.507866] [<c000000000b4f8f4>] .g5_cpufreq_init+0x9cc/0xa28
[ 20.507872] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
[ 20.507878] [<c000000000b0f86c>] .kernel_init_freeable+0x1ac/0x28c
[ 20.507883] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
[ 20.507887] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64
[ 20.507894]
[ 20.507894] -> #3 (subsys mutex#2){+.+.+.}:
[ 20.507899] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
[ 20.507903] [<c0000000004d7f24>] .bus_probe_device+0x44/0xe0
[ 20.507907] [<c0000000004d5208>] .device_add+0x508/0x730
[ 20.507911] [<c0000000004dd528>] .register_cpu+0x118/0x190
[ 20.507916] [<c000000000b14450>] .topology_init+0x148/0x248
[ 20.507921] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
[ 20.507925] [<c000000000b0f86c>] .kernel_init_freeable+0x1ac/0x28c
[ 20.507929] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
[ 20.507934] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64
[ 20.507939]
[ 20.507939] -> #2 (cpu_add_remove_lock){+.+.+.}:
[ 20.507944] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
[ 20.507950] [<c000000000087a9c>] .register_cpu_notifier+0x2c/0x70
[ 20.507955] [<c000000000b267e0>] .spawn_ksoftirqd+0x18/0x4c
[ 20.507959] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
[ 20.507964] [<c000000000b0f770>] .kernel_init_freeable+0xb0/0x28c
[ 20.507968] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
[ 20.507972] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64
[ 20.507978]
[ 20.507978] -> #1 (&host->mutex){+.+.+.}:
[ 20.507982] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
[ 20.507987] [<c0000000000527e8>] .kw_i2c_open+0x18/0x30
[ 20.507991] [<c000000000052894>] .pmac_i2c_open+0x94/0x100
[ 20.507995] [<c000000000b220a0>] .smp_core99_probe+0x260/0x410
[ 20.507999] [<c000000000b185bc>] .smp_prepare_cpus+0x280/0x2ac
[ 20.508003] [<c000000000b0f748>] .kernel_init_freeable+0x88/0x28c
[ 20.508008] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
[ 20.508012] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64
[ 20.508018]
[ 20.508018] -> #0 (&bus->mutex){+.+.+.}:
[ 20.508023] [<c0000000000ed5b4>] .lock_acquire+0x84/0x100
[ 20.508027] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
[ 20.508032] [<c000000000052830>] .pmac_i2c_open+0x30/0x100
[ 20.508037] [<c000000000052e14>] .pmac_i2c_do_begin+0x34/0x120
[ 20.508040] [<c000000000056bc0>] .pmf_call_one+0x50/0xd0
[ 20.508045] [<c00000000068ff1c>] .g5_pfunc_switch_volt+0x2c/0xc0
[ 20.508050] [<c00000000068fecc>] .g5_pfunc_switch_freq+0x1cc/0x1f0
[ 20.508054] [<c00000000068fc2c>] .g5_cpufreq_target+0x2c/0x40
[ 20.508058] [<c0000000006873ec>] .__cpufreq_driver_target+0x23c/0x840
[ 20.508062] [<c00000000068c798>] .cpufreq_gov_performance_limits+0x18/0x30
[ 20.508067] [<c00000000068915c>] .cpufreq_start_governor+0xac/0x100
[ 20.508071] [<c00000000068a788>] .cpufreq_set_policy+0x208/0x260
[ 20.508076] [<c00000000068abdc>] .cpufreq_init_policy+0x6c/0xb0
[ 20.508081] [<c00000000068ae70>] .cpufreq_online+0x250/0x9d0
[ 20.508085] [<c0000000004d76d8>] .subsys_interface_register+0xb8/0x110
[ 20.508090] [<c000000000689bb0>] .cpufreq_register_driver+0x1d0/0x250
[ 20.508094] [<c000000000b4f8f4>] .g5_cpufreq_init+0x9cc/0xa28
[ 20.508099] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
[ 20.508103] [<c000000000b0f86c>] .kernel_init_freeable+0x1ac/0x28c
[ 20.508107] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
[ 20.508112] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64
[ 20.508113]
[ 20.508113] other info that might help us debug this:
[ 20.508113]
[ 20.508121] Chain exists of:
[ 20.508121] &bus->mutex --> subsys mutex#2 --> &policy->rwsem
[ 20.508121]
[ 20.508123] Possible unsafe locking scenario:
[ 20.508123]
[ 20.508124] CPU0 CPU1
[ 20.508125] ---- ----
[ 20.508128] lock(&policy->rwsem);
[ 20.508132] lock(subsys mutex#2);
[ 20.508135] lock(&policy->rwsem);
[ 20.508138] lock(&bus->mutex);
[ 20.508139]
[ 20.508139] *** DEADLOCK ***
[ 20.508139]
[ 20.508141] 3 locks held by swapper/0/1:
[ 20.508150] #0: (cpu_hotplug.lock){++++++}, at: [<c000000000087838>] .get_online_cpus+0x48/0xc0
[ 20.508159] #1: (subsys mutex#2){+.+.+.}, at: [<c0000000004d7670>] .subsys_interface_register+0x50/0x110
[ 20.508168] #2: (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0
[ 20.508169]
[ 20.508169] stack backtrace:
[ 20.508173] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.8.0-rc7-00037-gd2ffb01 #21
[ 20.508175] Call Trace:
[ 20.508180] [c0000000790c2b90] [c00000000082cc70] .dump_stack+0xe0/0x14c (unreliable)
[ 20.508184] [c0000000790c2c20] [c000000000828c88] .print_circular_bug+0x350/0x388
[ 20.508188] [c0000000790c2cd0] [c0000000000ecb0c] .__lock_acquire+0x196c/0x1d30
[ 20.508192] [c0000000790c2e50] [c0000000000ed5b4] .lock_acquire+0x84/0x100
[ 20.508196] [c0000000790c2f20] [c000000000820448] .mutex_lock_nested+0xa8/0x590
[ 20.508201] [c0000000790c3030] [c000000000052830] .pmac_i2c_open+0x30/0x100
[ 20.508206] [c0000000790c30c0] [c000000000052e14] .pmac_i2c_do_begin+0x34/0x120
[ 20.508209] [c0000000790c3150] [c000000000056bc0] .pmf_call_one+0x50/0xd0
[ 20.508213] [c0000000790c31e0] [c00000000068ff1c] .g5_pfunc_switch_volt+0x2c/0xc0
[ 20.508217] [c0000000790c3250] [c00000000068fecc] .g5_pfunc_switch_freq+0x1cc/0x1f0
[ 20.508221] [c0000000790c3320] [c00000000068fc2c] .g5_cpufreq_target+0x2c/0x40
[ 20.508226] [c0000000790c3390] [c0000000006873ec] .__cpufreq_driver_target+0x23c/0x840
[ 20.508230] [c0000000790c3440] [c00000000068c798] .cpufreq_gov_performance_limits+0x18/0x30
[ 20.508235] [c0000000790c34b0] [c00000000068915c] .cpufreq_start_governor+0xac/0x100
[ 20.508239] [c0000000790c3530] [c00000000068a788] .cpufreq_set_policy+0x208/0x260
[ 20.508244] [c0000000790c35d0] [c00000000068abdc] .cpufreq_init_policy+0x6c/0xb0
[ 20.508249] [c0000000790c3940] [c00000000068ae70] .cpufreq_online+0x250/0x9d0
[ 20.508253] [c0000000790c3a30] [c0000000004d76d8] .subsys_interface_register+0xb8/0x110
[ 20.508258] [c0000000790c3ad0] [c000000000689bb0] .cpufreq_register_driver+0x1d0/0x250
[ 20.508262] [c0000000790c3b60] [c000000000b4f8f4] .g5_cpufreq_init+0x9cc/0xa28
[ 20.508267] [c0000000790c3c20] [c00000000000a98c] .do_one_initcall+0x5c/0x1d0
[ 20.508271] [c0000000790c3d00] [c000000000b0f86c] .kernel_init_freeable+0x1ac/0x28c
[ 20.508276] [c0000000790c3db0] [c00000000000b3bc] .kernel_init+0x1c/0x140
[ 20.508280] [c0000000790c3e30] [c0000000000098f4] .ret_from_kernel_thread+0x58/0x64
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
---
arch/powerpc/platforms/powermac/low_i2c.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/powerpc/platforms/powermac/low_i2c.c b/arch/powerpc/platforms/powermac/low_i2c.c
index 6d6f277..0159363 100644
--- a/arch/powerpc/platforms/powermac/low_i2c.c
+++ b/arch/powerpc/platforms/powermac/low_i2c.c
@@ -90,6 +90,7 @@ struct pmac_i2c_bus
int opened;
int polled; /* open mode */
struct platform_device *platform_dev;
+ struct lock_class_key lock_key;
/* ops */
int (*open)(struct pmac_i2c_bus *bus);
@@ -587,6 +588,7 @@ static void __init kw_i2c_add(struct pmac_i2c_host_kw *host,
bus->close = kw_i2c_close;
bus->xfer = kw_i2c_xfer;
mutex_init(&bus->mutex);
+ lockdep_set_class(&bus->mutex, &bus->lock_key);
if (controller == busnode)
bus->flags = pmac_i2c_multibus;
list_add(&bus->link, &pmac_i2c_busses);
@@ -815,6 +817,7 @@ static void __init pmu_i2c_probe(void)
bus->hostdata = bus + 1;
bus->xfer = pmu_i2c_xfer;
mutex_init(&bus->mutex);
+ lockdep_set_class(&bus->mutex, &bus->lock_key);
bus->flags = pmac_i2c_multibus;
list_add(&bus->link, &pmac_i2c_busses);
@@ -938,6 +941,7 @@ static void __init smu_i2c_probe(void)
bus->hostdata = bus + 1;
bus->xfer = smu_i2c_xfer;
mutex_init(&bus->mutex);
+ lockdep_set_class(&bus->mutex, &bus->lock_key);
bus->flags = 0;
list_add(&bus->link, &pmac_i2c_busses);
--
2.4.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] i2c_powermac: shut up lockdep warning
2016-09-21 11:34 [PATCH] i2c_powermac: shut up lockdep warning Denis Kirjanov
@ 2016-09-26 11:00 ` Denis Kirjanov
2016-09-26 21:03 ` Benjamin Herrenschmidt
2016-10-07 9:05 ` Denis Kirjanov
2016-11-14 12:17 ` Michael Ellerman
2 siblings, 1 reply; 7+ messages in thread
From: Denis Kirjanov @ 2016-09-26 11:00 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Michael Ellerman, Benjamin Herrenschmidt, Denis Kirjanov
[-- Attachment #1: Type: text/plain, Size: 10659 bytes --]
On Wednesday, September 21, 2016, Denis Kirjanov <kda@linux-powerpc.org>
wrote:
> That's unclear why lockdep shows the following warning but adding a
> lockdep class to struct pmac_i2c_bus solves it
HI Ben,
could you give any comments on this?
Thanks!
>
> [ 20.507795] ======================================================
> [ 20.507796] [ INFO: possible circular locking dependency detected ]
> [ 20.507800] 4.8.0-rc7-00037-gd2ffb01 #21 Not tainted
> [ 20.507801] -------------------------------------------------------
> [ 20.507803] swapper/0/1 is trying to acquire lock:
> [ 20.507818] (&bus->mutex){+.+.+.}, at: [<c000000000052830>]
> .pmac_i2c_open+0x30/0x100
> [ 20.507819]
> [ 20.507819] but task is already holding lock:
> [ 20.507829] (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>]
> .cpufreq_online+0x1ac/0x9d0
> [ 20.507830]
> [ 20.507830] which lock already depends on the new lock.
> [ 20.507830]
> [ 20.507832]
> [ 20.507832] the existing dependency chain (in reverse order) is:
> [ 20.507837]
> [ 20.507837] -> #4 (&policy->rwsem){+.+.+.}:
> [ 20.507844] [<c00000000082385c>] .down_write+0x6c/0x110
> [ 20.507849] [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0
> [ 20.507855] [<c0000000004d76d8>] .subsys_interface_register+
> 0xb8/0x110
> [ 20.507860] [<c000000000689bb0>] .cpufreq_register_driver+
> 0x1d0/0x250
> [ 20.507866] [<c000000000b4f8f4>] .g5_cpufreq_init+0x9cc/0xa28
> [ 20.507872] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
> [ 20.507878] [<c000000000b0f86c>] .kernel_init_freeable+0x1ac/
> 0x28c
> [ 20.507883] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.507887] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/
> 0x64
> [ 20.507894]
> [ 20.507894] -> #3 (subsys mutex#2){+.+.+.}:
> [ 20.507899] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
> [ 20.507903] [<c0000000004d7f24>] .bus_probe_device+0x44/0xe0
> [ 20.507907] [<c0000000004d5208>] .device_add+0x508/0x730
> [ 20.507911] [<c0000000004dd528>] .register_cpu+0x118/0x190
> [ 20.507916] [<c000000000b14450>] .topology_init+0x148/0x248
> [ 20.507921] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
> [ 20.507925] [<c000000000b0f86c>] .kernel_init_freeable+0x1ac/
> 0x28c
> [ 20.507929] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.507934] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/
> 0x64
> [ 20.507939]
> [ 20.507939] -> #2 (cpu_add_remove_lock){+.+.+.}:
> [ 20.507944] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
> [ 20.507950] [<c000000000087a9c>] .register_cpu_notifier+0x2c/
> 0x70
> [ 20.507955] [<c000000000b267e0>] .spawn_ksoftirqd+0x18/0x4c
> [ 20.507959] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
> [ 20.507964] [<c000000000b0f770>] .kernel_init_freeable+0xb0/
> 0x28c
> [ 20.507968] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.507972] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/
> 0x64
> [ 20.507978]
> [ 20.507978] -> #1 (&host->mutex){+.+.+.}:
> [ 20.507982] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
> [ 20.507987] [<c0000000000527e8>] .kw_i2c_open+0x18/0x30
> [ 20.507991] [<c000000000052894>] .pmac_i2c_open+0x94/0x100
> [ 20.507995] [<c000000000b220a0>] .smp_core99_probe+0x260/0x410
> [ 20.507999] [<c000000000b185bc>] .smp_prepare_cpus+0x280/0x2ac
> [ 20.508003] [<c000000000b0f748>] .kernel_init_freeable+0x88/
> 0x28c
> [ 20.508008] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.508012] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/
> 0x64
> [ 20.508018]
> [ 20.508018] -> #0 (&bus->mutex){+.+.+.}:
> [ 20.508023] [<c0000000000ed5b4>] .lock_acquire+0x84/0x100
> [ 20.508027] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
> [ 20.508032] [<c000000000052830>] .pmac_i2c_open+0x30/0x100
> [ 20.508037] [<c000000000052e14>] .pmac_i2c_do_begin+0x34/0x120
> [ 20.508040] [<c000000000056bc0>] .pmf_call_one+0x50/0xd0
> [ 20.508045] [<c00000000068ff1c>] .g5_pfunc_switch_volt+0x2c/0xc0
> [ 20.508050] [<c00000000068fecc>] .g5_pfunc_switch_freq+0x1cc/
> 0x1f0
> [ 20.508054] [<c00000000068fc2c>] .g5_cpufreq_target+0x2c/0x40
> [ 20.508058] [<c0000000006873ec>] .__cpufreq_driver_target+
> 0x23c/0x840
> [ 20.508062] [<c00000000068c798>] .cpufreq_gov_performance_
> limits+0x18/0x30
> [ 20.508067] [<c00000000068915c>] .cpufreq_start_governor+0xac/
> 0x100
> [ 20.508071] [<c00000000068a788>] .cpufreq_set_policy+0x208/0x260
> [ 20.508076] [<c00000000068abdc>] .cpufreq_init_policy+0x6c/0xb0
> [ 20.508081] [<c00000000068ae70>] .cpufreq_online+0x250/0x9d0
> [ 20.508085] [<c0000000004d76d8>] .subsys_interface_register+
> 0xb8/0x110
> [ 20.508090] [<c000000000689bb0>] .cpufreq_register_driver+
> 0x1d0/0x250
> [ 20.508094] [<c000000000b4f8f4>] .g5_cpufreq_init+0x9cc/0xa28
> [ 20.508099] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
> [ 20.508103] [<c000000000b0f86c>] .kernel_init_freeable+0x1ac/
> 0x28c
> [ 20.508107] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.508112] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/
> 0x64
> [ 20.508113]
> [ 20.508113] other info that might help us debug this:
> [ 20.508113]
> [ 20.508121] Chain exists of:
> [ 20.508121] &bus->mutex --> subsys mutex#2 --> &policy->rwsem
> [ 20.508121]
> [ 20.508123] Possible unsafe locking scenario:
> [ 20.508123]
> [ 20.508124] CPU0 CPU1
> [ 20.508125] ---- ----
> [ 20.508128] lock(&policy->rwsem);
> [ 20.508132] lock(subsys mutex#2);
> [ 20.508135] lock(&policy->rwsem);
> [ 20.508138] lock(&bus->mutex);
> [ 20.508139]
> [ 20.508139] *** DEADLOCK ***
> [ 20.508139]
> [ 20.508141] 3 locks held by swapper/0/1:
> [ 20.508150] #0: (cpu_hotplug.lock){++++++}, at: [<c000000000087838>]
> .get_online_cpus+0x48/0xc0
> [ 20.508159] #1: (subsys mutex#2){+.+.+.}, at: [<c0000000004d7670>]
> .subsys_interface_register+0x50/0x110
> [ 20.508168] #2: (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>]
> .cpufreq_online+0x1ac/0x9d0
> [ 20.508169]
> [ 20.508169] stack backtrace:
> [ 20.508173] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
> 4.8.0-rc7-00037-gd2ffb01 #21
> [ 20.508175] Call Trace:
> [ 20.508180] [c0000000790c2b90] [c00000000082cc70]
> .dump_stack+0xe0/0x14c (unreliable)
> [ 20.508184] [c0000000790c2c20] [c000000000828c88]
> .print_circular_bug+0x350/0x388
> [ 20.508188] [c0000000790c2cd0] [c0000000000ecb0c]
> .__lock_acquire+0x196c/0x1d30
> [ 20.508192] [c0000000790c2e50] [c0000000000ed5b4]
> .lock_acquire+0x84/0x100
> [ 20.508196] [c0000000790c2f20] [c000000000820448]
> .mutex_lock_nested+0xa8/0x590
> [ 20.508201] [c0000000790c3030] [c000000000052830]
> .pmac_i2c_open+0x30/0x100
> [ 20.508206] [c0000000790c30c0] [c000000000052e14]
> .pmac_i2c_do_begin+0x34/0x120
> [ 20.508209] [c0000000790c3150] [c000000000056bc0]
> .pmf_call_one+0x50/0xd0
> [ 20.508213] [c0000000790c31e0] [c00000000068ff1c]
> .g5_pfunc_switch_volt+0x2c/0xc0
> [ 20.508217] [c0000000790c3250] [c00000000068fecc]
> .g5_pfunc_switch_freq+0x1cc/0x1f0
> [ 20.508221] [c0000000790c3320] [c00000000068fc2c]
> .g5_cpufreq_target+0x2c/0x40
> [ 20.508226] [c0000000790c3390] [c0000000006873ec]
> .__cpufreq_driver_target+0x23c/0x840
> [ 20.508230] [c0000000790c3440] [c00000000068c798]
> .cpufreq_gov_performance_limits+0x18/0x30
> [ 20.508235] [c0000000790c34b0] [c00000000068915c]
> .cpufreq_start_governor+0xac/0x100
> [ 20.508239] [c0000000790c3530] [c00000000068a788]
> .cpufreq_set_policy+0x208/0x260
> [ 20.508244] [c0000000790c35d0] [c00000000068abdc]
> .cpufreq_init_policy+0x6c/0xb0
> [ 20.508249] [c0000000790c3940] [c00000000068ae70]
> .cpufreq_online+0x250/0x9d0
> [ 20.508253] [c0000000790c3a30] [c0000000004d76d8]
> .subsys_interface_register+0xb8/0x110
> [ 20.508258] [c0000000790c3ad0] [c000000000689bb0]
> .cpufreq_register_driver+0x1d0/0x250
> [ 20.508262] [c0000000790c3b60] [c000000000b4f8f4]
> .g5_cpufreq_init+0x9cc/0xa28
> [ 20.508267] [c0000000790c3c20] [c00000000000a98c]
> .do_one_initcall+0x5c/0x1d0
> [ 20.508271] [c0000000790c3d00] [c000000000b0f86c]
> .kernel_init_freeable+0x1ac/0x28c
> [ 20.508276] [c0000000790c3db0] [c00000000000b3bc]
> .kernel_init+0x1c/0x140
> [ 20.508280] [c0000000790c3e30] [c0000000000098f4]
> .ret_from_kernel_thread+0x58/0x64
>
> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org <javascript:;>>
> ---
> arch/powerpc/platforms/powermac/low_i2c.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/powerpc/platforms/powermac/low_i2c.c
> b/arch/powerpc/platforms/powermac/low_i2c.c
> index 6d6f277..0159363 100644
> --- a/arch/powerpc/platforms/powermac/low_i2c.c
> +++ b/arch/powerpc/platforms/powermac/low_i2c.c
> @@ -90,6 +90,7 @@ struct pmac_i2c_bus
> int opened;
> int polled; /* open mode */
> struct platform_device *platform_dev;
> + struct lock_class_key lock_key;
>
> /* ops */
> int (*open)(struct pmac_i2c_bus *bus);
> @@ -587,6 +588,7 @@ static void __init kw_i2c_add(struct pmac_i2c_host_kw
> *host,
> bus->close = kw_i2c_close;
> bus->xfer = kw_i2c_xfer;
> mutex_init(&bus->mutex);
> + lockdep_set_class(&bus->mutex, &bus->lock_key);
> if (controller == busnode)
> bus->flags = pmac_i2c_multibus;
> list_add(&bus->link, &pmac_i2c_busses);
> @@ -815,6 +817,7 @@ static void __init pmu_i2c_probe(void)
> bus->hostdata = bus + 1;
> bus->xfer = pmu_i2c_xfer;
> mutex_init(&bus->mutex);
> + lockdep_set_class(&bus->mutex, &bus->lock_key);
> bus->flags = pmac_i2c_multibus;
> list_add(&bus->link, &pmac_i2c_busses);
>
> @@ -938,6 +941,7 @@ static void __init smu_i2c_probe(void)
> bus->hostdata = bus + 1;
> bus->xfer = smu_i2c_xfer;
> mutex_init(&bus->mutex);
> + lockdep_set_class(&bus->mutex, &bus->lock_key);
> bus->flags = 0;
> list_add(&bus->link, &pmac_i2c_busses);
>
> --
> 2.4.0
>
>
[-- Attachment #2: Type: text/html, Size: 13026 bytes --]
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] i2c_powermac: shut up lockdep warning
2016-09-26 11:00 ` Denis Kirjanov
@ 2016-09-26 21:03 ` Benjamin Herrenschmidt
0 siblings, 0 replies; 7+ messages in thread
From: Benjamin Herrenschmidt @ 2016-09-26 21:03 UTC (permalink / raw)
To: Denis Kirjanov, linuxppc-dev
On Mon, 2016-09-26 at 14:00 +0300, Denis Kirjanov wrote:
>
>
> On Wednesday, September 21, 2016, Denis Kirjanov <kda@linux-powerpc.o
> rg> wrote:
> > That's unclear why lockdep shows the following warning but adding a
> > lockdep class to struct pmac_i2c_bus solves it
>
> HI Ben,
>
> could you give any comments on this?
I haven't quite figured out real reason for lockdep complaint, the
output is as usual terribly hard to parse, but adding a lock class
doesn't sound like something wrong to do so ...
Ben.
> Thanks!
> >
> > [ 20.507795]
> > ======================================================
> > [ 20.507796] [ INFO: possible circular locking dependency
> > detected ]
> > [ 20.507800] 4.8.0-rc7-00037-gd2ffb01 #21 Not tainted
> > [ 20.507801] ----------------------------------------------------
> > ---
> > [ 20.507803] swapper/0/1 is trying to acquire lock:
> > [ 20.507818] (&bus->mutex){+.+.+.}, at: [<c000000000052830>]
> > .pmac_i2c_open+0x30/0x100
> > [ 20.507819]
> > [ 20.507819] but task is already holding lock:
> > [ 20.507829] (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>]
> > .cpufreq_online+0x1ac/0x9d0
> > [ 20.507830]
> > [ 20.507830] which lock already depends on the new lock.
> > [ 20.507830]
> > [ 20.507832]
> > [ 20.507832] the existing dependency chain (in reverse order) is:
> > [ 20.507837]
> > [ 20.507837] -> #4 (&policy->rwsem){+.+.+.}:
> > [ 20.507844] [<c00000000082385c>] .down_write+0x6c/0x110
> > [ 20.507849] [<c00000000068adcc>]
> > .cpufreq_online+0x1ac/0x9d0
> > [ 20.507855] [<c0000000004d76d8>]
> > .subsys_interface_register+0xb8/0x110
> > [ 20.507860] [<c000000000689bb0>]
> > .cpufreq_register_driver+0x1d0/0x250
> > [ 20.507866] [<c000000000b4f8f4>]
> > .g5_cpufreq_init+0x9cc/0xa28
> > [ 20.507872] [<c00000000000a98c>]
> > .do_one_initcall+0x5c/0x1d0
> > [ 20.507878] [<c000000000b0f86c>]
> > .kernel_init_freeable+0x1ac/0x28c
> > [ 20.507883] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> > [ 20.507887] [<c0000000000098f4>]
> > .ret_from_kernel_thread+0x58/0x64
> > [ 20.507894]
> > [ 20.507894] -> #3 (subsys mutex#2){+.+.+.}:
> > [ 20.507899] [<c000000000820448>]
> > .mutex_lock_nested+0xa8/0x590
> > [ 20.507903] [<c0000000004d7f24>]
> > .bus_probe_device+0x44/0xe0
> > [ 20.507907] [<c0000000004d5208>] .device_add+0x508/0x730
> > [ 20.507911] [<c0000000004dd528>]
> > .register_cpu+0x118/0x190
> > [ 20.507916] [<c000000000b14450>]
> > .topology_init+0x148/0x248
> > [ 20.507921] [<c00000000000a98c>]
> > .do_one_initcall+0x5c/0x1d0
> > [ 20.507925] [<c000000000b0f86c>]
> > .kernel_init_freeable+0x1ac/0x28c
> > [ 20.507929] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> > [ 20.507934] [<c0000000000098f4>]
> > .ret_from_kernel_thread+0x58/0x64
> > [ 20.507939]
> > [ 20.507939] -> #2 (cpu_add_remove_lock){+.+.+.}:
> > [ 20.507944] [<c000000000820448>]
> > .mutex_lock_nested+0xa8/0x590
> > [ 20.507950] [<c000000000087a9c>]
> > .register_cpu_notifier+0x2c/0x70
> > [ 20.507955] [<c000000000b267e0>]
> > .spawn_ksoftirqd+0x18/0x4c
> > [ 20.507959] [<c00000000000a98c>]
> > .do_one_initcall+0x5c/0x1d0
> > [ 20.507964] [<c000000000b0f770>]
> > .kernel_init_freeable+0xb0/0x28c
> > [ 20.507968] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> > [ 20.507972] [<c0000000000098f4>]
> > .ret_from_kernel_thread+0x58/0x64
> > [ 20.507978]
> > [ 20.507978] -> #1 (&host->mutex){+.+.+.}:
> > [ 20.507982] [<c000000000820448>]
> > .mutex_lock_nested+0xa8/0x590
> > [ 20.507987] [<c0000000000527e8>] .kw_i2c_open+0x18/0x30
> > [ 20.507991] [<c000000000052894>]
> > .pmac_i2c_open+0x94/0x100
> > [ 20.507995] [<c000000000b220a0>]
> > .smp_core99_probe+0x260/0x410
> > [ 20.507999] [<c000000000b185bc>]
> > .smp_prepare_cpus+0x280/0x2ac
> > [ 20.508003] [<c000000000b0f748>]
> > .kernel_init_freeable+0x88/0x28c
> > [ 20.508008] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> > [ 20.508012] [<c0000000000098f4>]
> > .ret_from_kernel_thread+0x58/0x64
> > [ 20.508018]
> > [ 20.508018] -> #0 (&bus->mutex){+.+.+.}:
> > [ 20.508023] [<c0000000000ed5b4>] .lock_acquire+0x84/0x100
> > [ 20.508027] [<c000000000820448>]
> > .mutex_lock_nested+0xa8/0x590
> > [ 20.508032] [<c000000000052830>]
> > .pmac_i2c_open+0x30/0x100
> > [ 20.508037] [<c000000000052e14>]
> > .pmac_i2c_do_begin+0x34/0x120
> > [ 20.508040] [<c000000000056bc0>] .pmf_call_one+0x50/0xd0
> > [ 20.508045] [<c00000000068ff1c>]
> > .g5_pfunc_switch_volt+0x2c/0xc0
> > [ 20.508050] [<c00000000068fecc>]
> > .g5_pfunc_switch_freq+0x1cc/0x1f0
> > [ 20.508054] [<c00000000068fc2c>]
> > .g5_cpufreq_target+0x2c/0x40
> > [ 20.508058] [<c0000000006873ec>]
> > .__cpufreq_driver_target+0x23c/0x840
> > [ 20.508062] [<c00000000068c798>]
> > .cpufreq_gov_performance_limits+0x18/0x30
> > [ 20.508067] [<c00000000068915c>]
> > .cpufreq_start_governor+0xac/0x100
> > [ 20.508071] [<c00000000068a788>]
> > .cpufreq_set_policy+0x208/0x260
> > [ 20.508076] [<c00000000068abdc>]
> > .cpufreq_init_policy+0x6c/0xb0
> > [ 20.508081] [<c00000000068ae70>]
> > .cpufreq_online+0x250/0x9d0
> > [ 20.508085] [<c0000000004d76d8>]
> > .subsys_interface_register+0xb8/0x110
> > [ 20.508090] [<c000000000689bb0>]
> > .cpufreq_register_driver+0x1d0/0x250
> > [ 20.508094] [<c000000000b4f8f4>]
> > .g5_cpufreq_init+0x9cc/0xa28
> > [ 20.508099] [<c00000000000a98c>]
> > .do_one_initcall+0x5c/0x1d0
> > [ 20.508103] [<c000000000b0f86c>]
> > .kernel_init_freeable+0x1ac/0x28c
> > [ 20.508107] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> > [ 20.508112] [<c0000000000098f4>]
> > .ret_from_kernel_thread+0x58/0x64
> > [ 20.508113]
> > [ 20.508113] other info that might help us debug this:
> > [ 20.508113]
> > [ 20.508121] Chain exists of:
> > [ 20.508121] &bus->mutex --> subsys mutex#2 --> &policy->rwsem
> > [ 20.508121]
> > [ 20.508123] Possible unsafe locking scenario:
> > [ 20.508123]
> > [ 20.508124] CPU0 CPU1
> > [ 20.508125] ---- ----
> > [ 20.508128] lock(&policy->rwsem);
> > [ 20.508132] lock(subsys mutex#2);
> > [ 20.508135] lock(&policy->rwsem);
> > [ 20.508138] lock(&bus->mutex);
> > [ 20.508139]
> > [ 20.508139] *** DEADLOCK ***
> > [ 20.508139]
> > [ 20.508141] 3 locks held by swapper/0/1:
> > [ 20.508150] #0: (cpu_hotplug.lock){++++++}, at:
> > [<c000000000087838>] .get_online_cpus+0x48/0xc0
> > [ 20.508159] #1: (subsys mutex#2){+.+.+.}, at:
> > [<c0000000004d7670>] .subsys_interface_register+0x50/0x110
> > [ 20.508168] #2: (&policy->rwsem){+.+.+.}, at:
> > [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0
> > [ 20.508169]
> > [ 20.508169] stack backtrace:
> > [ 20.508173] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.8.0-rc7-
> > 00037-gd2ffb01 #21
> > [ 20.508175] Call Trace:
> > [ 20.508180] [c0000000790c2b90] [c00000000082cc70]
> > .dump_stack+0xe0/0x14c (unreliable)
> > [ 20.508184] [c0000000790c2c20] [c000000000828c88]
> > .print_circular_bug+0x350/0x388
> > [ 20.508188] [c0000000790c2cd0] [c0000000000ecb0c]
> > .__lock_acquire+0x196c/0x1d30
> > [ 20.508192] [c0000000790c2e50] [c0000000000ed5b4]
> > .lock_acquire+0x84/0x100
> > [ 20.508196] [c0000000790c2f20] [c000000000820448]
> > .mutex_lock_nested+0xa8/0x590
> > [ 20.508201] [c0000000790c3030] [c000000000052830]
> > .pmac_i2c_open+0x30/0x100
> > [ 20.508206] [c0000000790c30c0] [c000000000052e14]
> > .pmac_i2c_do_begin+0x34/0x120
> > [ 20.508209] [c0000000790c3150] [c000000000056bc0]
> > .pmf_call_one+0x50/0xd0
> > [ 20.508213] [c0000000790c31e0] [c00000000068ff1c]
> > .g5_pfunc_switch_volt+0x2c/0xc0
> > [ 20.508217] [c0000000790c3250] [c00000000068fecc]
> > .g5_pfunc_switch_freq+0x1cc/0x1f0
> > [ 20.508221] [c0000000790c3320] [c00000000068fc2c]
> > .g5_cpufreq_target+0x2c/0x40
> > [ 20.508226] [c0000000790c3390] [c0000000006873ec]
> > .__cpufreq_driver_target+0x23c/0x840
> > [ 20.508230] [c0000000790c3440] [c00000000068c798]
> > .cpufreq_gov_performance_limits+0x18/0x30
> > [ 20.508235] [c0000000790c34b0] [c00000000068915c]
> > .cpufreq_start_governor+0xac/0x100
> > [ 20.508239] [c0000000790c3530] [c00000000068a788]
> > .cpufreq_set_policy+0x208/0x260
> > [ 20.508244] [c0000000790c35d0] [c00000000068abdc]
> > .cpufreq_init_policy+0x6c/0xb0
> > [ 20.508249] [c0000000790c3940] [c00000000068ae70]
> > .cpufreq_online+0x250/0x9d0
> > [ 20.508253] [c0000000790c3a30] [c0000000004d76d8]
> > .subsys_interface_register+0xb8/0x110
> > [ 20.508258] [c0000000790c3ad0] [c000000000689bb0]
> > .cpufreq_register_driver+0x1d0/0x250
> > [ 20.508262] [c0000000790c3b60] [c000000000b4f8f4]
> > .g5_cpufreq_init+0x9cc/0xa28
> > [ 20.508267] [c0000000790c3c20] [c00000000000a98c]
> > .do_one_initcall+0x5c/0x1d0
> > [ 20.508271] [c0000000790c3d00] [c000000000b0f86c]
> > .kernel_init_freeable+0x1ac/0x28c
> > [ 20.508276] [c0000000790c3db0] [c00000000000b3bc]
> > .kernel_init+0x1c/0x140
> > [ 20.508280] [c0000000790c3e30] [c0000000000098f4]
> > .ret_from_kernel_thread+0x58/0x64
> >
> > Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
> > ---
> > arch/powerpc/platforms/powermac/low_i2c.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/arch/powerpc/platforms/powermac/low_i2c.c
> > b/arch/powerpc/platforms/powermac/low_i2c.c
> > index 6d6f277..0159363 100644
> > --- a/arch/powerpc/platforms/powermac/low_i2c.c
> > +++ b/arch/powerpc/platforms/powermac/low_i2c.c
> > @@ -90,6 +90,7 @@ struct pmac_i2c_bus
> > int opened;
> > int polled; /* open mode */
> > struct platform_device *platform_dev;
> > + struct lock_class_key lock_key;
> >
> > /* ops */
> > int (*open)(struct pmac_i2c_bus *bus);
> > @@ -587,6 +588,7 @@ static void __init kw_i2c_add(struct
> > pmac_i2c_host_kw *host,
> > bus->close = kw_i2c_close;
> > bus->xfer = kw_i2c_xfer;
> > mutex_init(&bus->mutex);
> > + lockdep_set_class(&bus->mutex, &bus->lock_key);
> > if (controller == busnode)
> > bus->flags = pmac_i2c_multibus;
> > list_add(&bus->link, &pmac_i2c_busses);
> > @@ -815,6 +817,7 @@ static void __init pmu_i2c_probe(void)
> > bus->hostdata = bus + 1;
> > bus->xfer = pmu_i2c_xfer;
> > mutex_init(&bus->mutex);
> > + lockdep_set_class(&bus->mutex, &bus->lock_key);
> > bus->flags = pmac_i2c_multibus;
> > list_add(&bus->link, &pmac_i2c_busses);
> >
> > @@ -938,6 +941,7 @@ static void __init smu_i2c_probe(void)
> > bus->hostdata = bus + 1;
> > bus->xfer = smu_i2c_xfer;
> > mutex_init(&bus->mutex);
> > + lockdep_set_class(&bus->mutex, &bus->lock_key);
> > bus->flags = 0;
> > list_add(&bus->link, &pmac_i2c_busses);
> >
> > --
> > 2.4.0
> >
> >
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] i2c_powermac: shut up lockdep warning
2016-09-21 11:34 [PATCH] i2c_powermac: shut up lockdep warning Denis Kirjanov
2016-09-26 11:00 ` Denis Kirjanov
@ 2016-10-07 9:05 ` Denis Kirjanov
2016-10-10 5:35 ` Michael Ellerman
2016-11-14 12:17 ` Michael Ellerman
2 siblings, 1 reply; 7+ messages in thread
From: Denis Kirjanov @ 2016-10-07 9:05 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Michael Ellerman, Benjamin Herrenschmidt, Denis Kirjanov
On 9/21/16, Denis Kirjanov <kda@linux-powerpc.org> wrote:
> That's unclear why lockdep shows the following warning but adding a
> lockdep class to struct pmac_i2c_bus solves it
>
> [ 20.507795] ======================================================
> [ 20.507796] [ INFO: possible circular locking dependency detected ]
> [ 20.507800] 4.8.0-rc7-00037-gd2ffb01 #21 Not tainted
> [ 20.507801] -------------------------------------------------------
> [ 20.507803] swapper/0/1 is trying to acquire lock:
> [ 20.507818] (&bus->mutex){+.+.+.}, at: [<c000000000052830>]
> .pmac_i2c_open+0x30/0x100
> [ 20.507819]
> [ 20.507819] but task is already holding lock:
> [ 20.507829] (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>]
> .cpufreq_online+0x1ac/0x9d0
> [ 20.507830]
> [ 20.507830] which lock already depends on the new lock.
> [ 20.507830]
> [ 20.507832]
> [ 20.507832] the existing dependency chain (in reverse order) is:
> [ 20.507837]
> [ 20.507837] -> #4 (&policy->rwsem){+.+.+.}:
> [ 20.507844] [<c00000000082385c>] .down_write+0x6c/0x110
> [ 20.507849] [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0
> [ 20.507855] [<c0000000004d76d8>]
> .subsys_interface_register+0xb8/0x110
> [ 20.507860] [<c000000000689bb0>]
> .cpufreq_register_driver+0x1d0/0x250
> [ 20.507866] [<c000000000b4f8f4>] .g5_cpufreq_init+0x9cc/0xa28
> [ 20.507872] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
> [ 20.507878] [<c000000000b0f86c>]
> .kernel_init_freeable+0x1ac/0x28c
> [ 20.507883] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.507887] [<c0000000000098f4>]
> .ret_from_kernel_thread+0x58/0x64
> [ 20.507894]
> [ 20.507894] -> #3 (subsys mutex#2){+.+.+.}:
> [ 20.507899] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
> [ 20.507903] [<c0000000004d7f24>] .bus_probe_device+0x44/0xe0
> [ 20.507907] [<c0000000004d5208>] .device_add+0x508/0x730
> [ 20.507911] [<c0000000004dd528>] .register_cpu+0x118/0x190
> [ 20.507916] [<c000000000b14450>] .topology_init+0x148/0x248
> [ 20.507921] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
> [ 20.507925] [<c000000000b0f86c>]
> .kernel_init_freeable+0x1ac/0x28c
> [ 20.507929] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.507934] [<c0000000000098f4>]
> .ret_from_kernel_thread+0x58/0x64
> [ 20.507939]
> [ 20.507939] -> #2 (cpu_add_remove_lock){+.+.+.}:
> [ 20.507944] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
> [ 20.507950] [<c000000000087a9c>] .register_cpu_notifier+0x2c/0x70
> [ 20.507955] [<c000000000b267e0>] .spawn_ksoftirqd+0x18/0x4c
> [ 20.507959] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
> [ 20.507964] [<c000000000b0f770>] .kernel_init_freeable+0xb0/0x28c
> [ 20.507968] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.507972] [<c0000000000098f4>]
> .ret_from_kernel_thread+0x58/0x64
> [ 20.507978]
> [ 20.507978] -> #1 (&host->mutex){+.+.+.}:
> [ 20.507982] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
> [ 20.507987] [<c0000000000527e8>] .kw_i2c_open+0x18/0x30
> [ 20.507991] [<c000000000052894>] .pmac_i2c_open+0x94/0x100
> [ 20.507995] [<c000000000b220a0>] .smp_core99_probe+0x260/0x410
> [ 20.507999] [<c000000000b185bc>] .smp_prepare_cpus+0x280/0x2ac
> [ 20.508003] [<c000000000b0f748>] .kernel_init_freeable+0x88/0x28c
> [ 20.508008] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.508012] [<c0000000000098f4>]
> .ret_from_kernel_thread+0x58/0x64
> [ 20.508018]
> [ 20.508018] -> #0 (&bus->mutex){+.+.+.}:
> [ 20.508023] [<c0000000000ed5b4>] .lock_acquire+0x84/0x100
> [ 20.508027] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
> [ 20.508032] [<c000000000052830>] .pmac_i2c_open+0x30/0x100
> [ 20.508037] [<c000000000052e14>] .pmac_i2c_do_begin+0x34/0x120
> [ 20.508040] [<c000000000056bc0>] .pmf_call_one+0x50/0xd0
> [ 20.508045] [<c00000000068ff1c>] .g5_pfunc_switch_volt+0x2c/0xc0
> [ 20.508050] [<c00000000068fecc>]
> .g5_pfunc_switch_freq+0x1cc/0x1f0
> [ 20.508054] [<c00000000068fc2c>] .g5_cpufreq_target+0x2c/0x40
> [ 20.508058] [<c0000000006873ec>]
> .__cpufreq_driver_target+0x23c/0x840
> [ 20.508062] [<c00000000068c798>]
> .cpufreq_gov_performance_limits+0x18/0x30
> [ 20.508067] [<c00000000068915c>]
> .cpufreq_start_governor+0xac/0x100
> [ 20.508071] [<c00000000068a788>] .cpufreq_set_policy+0x208/0x260
> [ 20.508076] [<c00000000068abdc>] .cpufreq_init_policy+0x6c/0xb0
> [ 20.508081] [<c00000000068ae70>] .cpufreq_online+0x250/0x9d0
> [ 20.508085] [<c0000000004d76d8>]
> .subsys_interface_register+0xb8/0x110
> [ 20.508090] [<c000000000689bb0>]
> .cpufreq_register_driver+0x1d0/0x250
> [ 20.508094] [<c000000000b4f8f4>] .g5_cpufreq_init+0x9cc/0xa28
> [ 20.508099] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
> [ 20.508103] [<c000000000b0f86c>]
> .kernel_init_freeable+0x1ac/0x28c
> [ 20.508107] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.508112] [<c0000000000098f4>]
> .ret_from_kernel_thread+0x58/0x64
> [ 20.508113]
> [ 20.508113] other info that might help us debug this:
> [ 20.508113]
> [ 20.508121] Chain exists of:
> [ 20.508121] &bus->mutex --> subsys mutex#2 --> &policy->rwsem
> [ 20.508121]
> [ 20.508123] Possible unsafe locking scenario:
> [ 20.508123]
> [ 20.508124] CPU0 CPU1
> [ 20.508125] ---- ----
> [ 20.508128] lock(&policy->rwsem);
> [ 20.508132] lock(subsys mutex#2);
> [ 20.508135] lock(&policy->rwsem);
> [ 20.508138] lock(&bus->mutex);
> [ 20.508139]
> [ 20.508139] *** DEADLOCK ***
> [ 20.508139]
> [ 20.508141] 3 locks held by swapper/0/1:
> [ 20.508150] #0: (cpu_hotplug.lock){++++++}, at: [<c000000000087838>]
> .get_online_cpus+0x48/0xc0
> [ 20.508159] #1: (subsys mutex#2){+.+.+.}, at: [<c0000000004d7670>]
> .subsys_interface_register+0x50/0x110
> [ 20.508168] #2: (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>]
> .cpufreq_online+0x1ac/0x9d0
> [ 20.508169]
> [ 20.508169] stack backtrace:
> [ 20.508173] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
> 4.8.0-rc7-00037-gd2ffb01 #21
> [ 20.508175] Call Trace:
> [ 20.508180] [c0000000790c2b90] [c00000000082cc70] .dump_stack+0xe0/0x14c
> (unreliable)
> [ 20.508184] [c0000000790c2c20] [c000000000828c88]
> .print_circular_bug+0x350/0x388
> [ 20.508188] [c0000000790c2cd0] [c0000000000ecb0c]
> .__lock_acquire+0x196c/0x1d30
> [ 20.508192] [c0000000790c2e50] [c0000000000ed5b4]
> .lock_acquire+0x84/0x100
> [ 20.508196] [c0000000790c2f20] [c000000000820448]
> .mutex_lock_nested+0xa8/0x590
> [ 20.508201] [c0000000790c3030] [c000000000052830]
> .pmac_i2c_open+0x30/0x100
> [ 20.508206] [c0000000790c30c0] [c000000000052e14]
> .pmac_i2c_do_begin+0x34/0x120
> [ 20.508209] [c0000000790c3150] [c000000000056bc0]
> .pmf_call_one+0x50/0xd0
> [ 20.508213] [c0000000790c31e0] [c00000000068ff1c]
> .g5_pfunc_switch_volt+0x2c/0xc0
> [ 20.508217] [c0000000790c3250] [c00000000068fecc]
> .g5_pfunc_switch_freq+0x1cc/0x1f0
> [ 20.508221] [c0000000790c3320] [c00000000068fc2c]
> .g5_cpufreq_target+0x2c/0x40
> [ 20.508226] [c0000000790c3390] [c0000000006873ec]
> .__cpufreq_driver_target+0x23c/0x840
> [ 20.508230] [c0000000790c3440] [c00000000068c798]
> .cpufreq_gov_performance_limits+0x18/0x30
> [ 20.508235] [c0000000790c34b0] [c00000000068915c]
> .cpufreq_start_governor+0xac/0x100
> [ 20.508239] [c0000000790c3530] [c00000000068a788]
> .cpufreq_set_policy+0x208/0x260
> [ 20.508244] [c0000000790c35d0] [c00000000068abdc]
> .cpufreq_init_policy+0x6c/0xb0
> [ 20.508249] [c0000000790c3940] [c00000000068ae70]
> .cpufreq_online+0x250/0x9d0
> [ 20.508253] [c0000000790c3a30] [c0000000004d76d8]
> .subsys_interface_register+0xb8/0x110
> [ 20.508258] [c0000000790c3ad0] [c000000000689bb0]
> .cpufreq_register_driver+0x1d0/0x250
> [ 20.508262] [c0000000790c3b60] [c000000000b4f8f4]
> .g5_cpufreq_init+0x9cc/0xa28
> [ 20.508267] [c0000000790c3c20] [c00000000000a98c]
> .do_one_initcall+0x5c/0x1d0
> [ 20.508271] [c0000000790c3d00] [c000000000b0f86c]
> .kernel_init_freeable+0x1ac/0x28c
> [ 20.508276] [c0000000790c3db0] [c00000000000b3bc]
> .kernel_init+0x1c/0x140
> [ 20.508280] [c0000000790c3e30] [c0000000000098f4]
> .ret_from_kernel_thread+0x58/0x64
>
> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
> ---
Hi Michael,
are you going to take this patch? The issue appears to me for a long time
Thanks!
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] i2c_powermac: shut up lockdep warning
2016-10-07 9:05 ` Denis Kirjanov
@ 2016-10-10 5:35 ` Michael Ellerman
2016-10-10 7:25 ` Benjamin Herrenschmidt
0 siblings, 1 reply; 7+ messages in thread
From: Michael Ellerman @ 2016-10-10 5:35 UTC (permalink / raw)
To: Denis Kirjanov, linuxppc-dev; +Cc: Benjamin Herrenschmidt, Denis Kirjanov
Denis Kirjanov <kda@linux-powerpc.org> writes:
> On 9/21/16, Denis Kirjanov <kda@linux-powerpc.org> wrote:
>> That's unclear why lockdep shows the following warning but adding a
>> lockdep class to struct pmac_i2c_bus solves it
>>
>> [ 20.507795] ======================================================
>> [ 20.507796] [ INFO: possible circular locking dependency detected ]
>> [ 20.507800] 4.8.0-rc7-00037-gd2ffb01 #21 Not tainted
>> [ 20.507801] -------------------------------------------------------
>> [ 20.507803] swapper/0/1 is trying to acquire lock:
>> [ 20.507818] (&bus->mutex){+.+.+.}, at: [<c000000000052830>]
>> .pmac_i2c_open+0x30/0x100
>> [ 20.507819]
>> [ 20.507819] but task is already holding lock:
>> [ 20.507829] (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>]
>> .cpufreq_online+0x1ac/0x9d0
>> [ 20.507830]
>> [ 20.507830] which lock already depends on the new lock.
>> [ 20.507830]
>> [ 20.507832]
>> [ 20.507832] the existing dependency chain (in reverse order) is:
>> [ 20.507837]
>> [ 20.507837] -> #4 (&policy->rwsem){+.+.+.}:
>> [ 20.507844] [<c00000000082385c>] .down_write+0x6c/0x110
>> [ 20.507849] [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0
>> [ 20.507855] [<c0000000004d76d8>]
>> .subsys_interface_register+0xb8/0x110
>> [ 20.507860] [<c000000000689bb0>]
>> .cpufreq_register_driver+0x1d0/0x250
>> [ 20.507866] [<c000000000b4f8f4>] .g5_cpufreq_init+0x9cc/0xa28
>> [ 20.507872] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
>> [ 20.507878] [<c000000000b0f86c>]
>> .kernel_init_freeable+0x1ac/0x28c
>> [ 20.507883] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
>> [ 20.507887] [<c0000000000098f4>]
>> .ret_from_kernel_thread+0x58/0x64
>> [ 20.507894]
>> [ 20.507894] -> #3 (subsys mutex#2){+.+.+.}:
>> [ 20.507899] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
>> [ 20.507903] [<c0000000004d7f24>] .bus_probe_device+0x44/0xe0
>> [ 20.507907] [<c0000000004d5208>] .device_add+0x508/0x730
>> [ 20.507911] [<c0000000004dd528>] .register_cpu+0x118/0x190
>> [ 20.507916] [<c000000000b14450>] .topology_init+0x148/0x248
>> [ 20.507921] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
>> [ 20.507925] [<c000000000b0f86c>]
>> .kernel_init_freeable+0x1ac/0x28c
>> [ 20.507929] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
>> [ 20.507934] [<c0000000000098f4>]
>> .ret_from_kernel_thread+0x58/0x64
>> [ 20.507939]
>> [ 20.507939] -> #2 (cpu_add_remove_lock){+.+.+.}:
>> [ 20.507944] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
>> [ 20.507950] [<c000000000087a9c>] .register_cpu_notifier+0x2c/0x70
>> [ 20.507955] [<c000000000b267e0>] .spawn_ksoftirqd+0x18/0x4c
>> [ 20.507959] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
>> [ 20.507964] [<c000000000b0f770>] .kernel_init_freeable+0xb0/0x28c
>> [ 20.507968] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
>> [ 20.507972] [<c0000000000098f4>]
>> .ret_from_kernel_thread+0x58/0x64
>> [ 20.507978]
>> [ 20.507978] -> #1 (&host->mutex){+.+.+.}:
>> [ 20.507982] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
>> [ 20.507987] [<c0000000000527e8>] .kw_i2c_open+0x18/0x30
>> [ 20.507991] [<c000000000052894>] .pmac_i2c_open+0x94/0x100
>> [ 20.507995] [<c000000000b220a0>] .smp_core99_probe+0x260/0x410
>> [ 20.507999] [<c000000000b185bc>] .smp_prepare_cpus+0x280/0x2ac
>> [ 20.508003] [<c000000000b0f748>] .kernel_init_freeable+0x88/0x28c
>> [ 20.508008] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
>> [ 20.508012] [<c0000000000098f4>]
>> .ret_from_kernel_thread+0x58/0x64
>> [ 20.508018]
>> [ 20.508018] -> #0 (&bus->mutex){+.+.+.}:
>> [ 20.508023] [<c0000000000ed5b4>] .lock_acquire+0x84/0x100
>> [ 20.508027] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
>> [ 20.508032] [<c000000000052830>] .pmac_i2c_open+0x30/0x100
>> [ 20.508037] [<c000000000052e14>] .pmac_i2c_do_begin+0x34/0x120
>> [ 20.508040] [<c000000000056bc0>] .pmf_call_one+0x50/0xd0
>> [ 20.508045] [<c00000000068ff1c>] .g5_pfunc_switch_volt+0x2c/0xc0
>> [ 20.508050] [<c00000000068fecc>]
>> .g5_pfunc_switch_freq+0x1cc/0x1f0
>> [ 20.508054] [<c00000000068fc2c>] .g5_cpufreq_target+0x2c/0x40
>> [ 20.508058] [<c0000000006873ec>]
>> .__cpufreq_driver_target+0x23c/0x840
>> [ 20.508062] [<c00000000068c798>]
>> .cpufreq_gov_performance_limits+0x18/0x30
>> [ 20.508067] [<c00000000068915c>]
>> .cpufreq_start_governor+0xac/0x100
>> [ 20.508071] [<c00000000068a788>] .cpufreq_set_policy+0x208/0x260
>> [ 20.508076] [<c00000000068abdc>] .cpufreq_init_policy+0x6c/0xb0
>> [ 20.508081] [<c00000000068ae70>] .cpufreq_online+0x250/0x9d0
>> [ 20.508085] [<c0000000004d76d8>]
>> .subsys_interface_register+0xb8/0x110
>> [ 20.508090] [<c000000000689bb0>]
>> .cpufreq_register_driver+0x1d0/0x250
>> [ 20.508094] [<c000000000b4f8f4>] .g5_cpufreq_init+0x9cc/0xa28
>> [ 20.508099] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
>> [ 20.508103] [<c000000000b0f86c>]
>> .kernel_init_freeable+0x1ac/0x28c
>> [ 20.508107] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
>> [ 20.508112] [<c0000000000098f4>]
>> .ret_from_kernel_thread+0x58/0x64
>> [ 20.508113]
>> [ 20.508113] other info that might help us debug this:
>> [ 20.508113]
>> [ 20.508121] Chain exists of:
>> [ 20.508121] &bus->mutex --> subsys mutex#2 --> &policy->rwsem
>> [ 20.508121]
>> [ 20.508123] Possible unsafe locking scenario:
>> [ 20.508123]
>> [ 20.508124] CPU0 CPU1
>> [ 20.508125] ---- ----
>> [ 20.508128] lock(&policy->rwsem);
>> [ 20.508132] lock(subsys mutex#2);
>> [ 20.508135] lock(&policy->rwsem);
>> [ 20.508138] lock(&bus->mutex);
>> [ 20.508139]
>> [ 20.508139] *** DEADLOCK ***
>> [ 20.508139]
>> [ 20.508141] 3 locks held by swapper/0/1:
>> [ 20.508150] #0: (cpu_hotplug.lock){++++++}, at: [<c000000000087838>]
>> .get_online_cpus+0x48/0xc0
>> [ 20.508159] #1: (subsys mutex#2){+.+.+.}, at: [<c0000000004d7670>]
>> .subsys_interface_register+0x50/0x110
>> [ 20.508168] #2: (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>]
>> .cpufreq_online+0x1ac/0x9d0
>> [ 20.508169]
>> [ 20.508169] stack backtrace:
>> [ 20.508173] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
>> 4.8.0-rc7-00037-gd2ffb01 #21
>> [ 20.508175] Call Trace:
>> [ 20.508180] [c0000000790c2b90] [c00000000082cc70] .dump_stack+0xe0/0x14c
>> (unreliable)
>> [ 20.508184] [c0000000790c2c20] [c000000000828c88]
>> .print_circular_bug+0x350/0x388
>> [ 20.508188] [c0000000790c2cd0] [c0000000000ecb0c]
>> .__lock_acquire+0x196c/0x1d30
>> [ 20.508192] [c0000000790c2e50] [c0000000000ed5b4]
>> .lock_acquire+0x84/0x100
>> [ 20.508196] [c0000000790c2f20] [c000000000820448]
>> .mutex_lock_nested+0xa8/0x590
>> [ 20.508201] [c0000000790c3030] [c000000000052830]
>> .pmac_i2c_open+0x30/0x100
>> [ 20.508206] [c0000000790c30c0] [c000000000052e14]
>> .pmac_i2c_do_begin+0x34/0x120
>> [ 20.508209] [c0000000790c3150] [c000000000056bc0]
>> .pmf_call_one+0x50/0xd0
>> [ 20.508213] [c0000000790c31e0] [c00000000068ff1c]
>> .g5_pfunc_switch_volt+0x2c/0xc0
>> [ 20.508217] [c0000000790c3250] [c00000000068fecc]
>> .g5_pfunc_switch_freq+0x1cc/0x1f0
>> [ 20.508221] [c0000000790c3320] [c00000000068fc2c]
>> .g5_cpufreq_target+0x2c/0x40
>> [ 20.508226] [c0000000790c3390] [c0000000006873ec]
>> .__cpufreq_driver_target+0x23c/0x840
>> [ 20.508230] [c0000000790c3440] [c00000000068c798]
>> .cpufreq_gov_performance_limits+0x18/0x30
>> [ 20.508235] [c0000000790c34b0] [c00000000068915c]
>> .cpufreq_start_governor+0xac/0x100
>> [ 20.508239] [c0000000790c3530] [c00000000068a788]
>> .cpufreq_set_policy+0x208/0x260
>> [ 20.508244] [c0000000790c35d0] [c00000000068abdc]
>> .cpufreq_init_policy+0x6c/0xb0
>> [ 20.508249] [c0000000790c3940] [c00000000068ae70]
>> .cpufreq_online+0x250/0x9d0
>> [ 20.508253] [c0000000790c3a30] [c0000000004d76d8]
>> .subsys_interface_register+0xb8/0x110
>> [ 20.508258] [c0000000790c3ad0] [c000000000689bb0]
>> .cpufreq_register_driver+0x1d0/0x250
>> [ 20.508262] [c0000000790c3b60] [c000000000b4f8f4]
>> .g5_cpufreq_init+0x9cc/0xa28
>> [ 20.508267] [c0000000790c3c20] [c00000000000a98c]
>> .do_one_initcall+0x5c/0x1d0
>> [ 20.508271] [c0000000790c3d00] [c000000000b0f86c]
>> .kernel_init_freeable+0x1ac/0x28c
>> [ 20.508276] [c0000000790c3db0] [c00000000000b3bc]
>> .kernel_init+0x1c/0x140
>> [ 20.508280] [c0000000790c3e30] [c0000000000098f4]
>> .ret_from_kernel_thread+0x58/0x64
>>
>> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
>> ---
>
> Hi Michael,
>
> are you going to take this patch? The issue appears to me for a long time
I guess. Ben's response was a bit equivocal. But I guess he meant "seems
OK". So yeah I'll pick it up for 4.10.
cheers
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] i2c_powermac: shut up lockdep warning
2016-10-10 5:35 ` Michael Ellerman
@ 2016-10-10 7:25 ` Benjamin Herrenschmidt
0 siblings, 0 replies; 7+ messages in thread
From: Benjamin Herrenschmidt @ 2016-10-10 7:25 UTC (permalink / raw)
To: Michael Ellerman, Denis Kirjanov, linuxppc-dev
On Mon, 2016-10-10 at 16:35 +1100, Michael Ellerman wrote:
> > are you going to take this patch? The issue appears to me for a
> long time
>
> I guess. Ben's response was a bit equivocal. But I guess he meant
> "seems
> OK". So yeah I'll pick it up for 4.10.
Yeah... seems ok. I haven't touched that code in many years...
Ben.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: i2c_powermac: shut up lockdep warning
2016-09-21 11:34 [PATCH] i2c_powermac: shut up lockdep warning Denis Kirjanov
2016-09-26 11:00 ` Denis Kirjanov
2016-10-07 9:05 ` Denis Kirjanov
@ 2016-11-14 12:17 ` Michael Ellerman
2 siblings, 0 replies; 7+ messages in thread
From: Michael Ellerman @ 2016-11-14 12:17 UTC (permalink / raw)
To: Denis Kirjanov, linuxppc-dev; +Cc: Denis Kirjanov
On Wed, 2016-21-09 at 11:34:58 UTC, Denis Kirjanov wrote:
> That's unclear why lockdep shows the following warning but adding a
> lockdep class to struct pmac_i2c_bus solves it
>
> [ 20.507795] ======================================================
> [ 20.507796] [ INFO: possible circular locking dependency detected ]
> [ 20.507800] 4.8.0-rc7-00037-gd2ffb01 #21 Not tainted
> [ 20.507801] -------------------------------------------------------
> [ 20.507803] swapper/0/1 is trying to acquire lock:
> [ 20.507818] (&bus->mutex){+.+.+.}, at: [<c000000000052830>] .pmac_i2c_open+0x30/0x100
> [ 20.507819]
> [ 20.507819] but task is already holding lock:
> [ 20.507829] (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0
> [ 20.507830]
> [ 20.507830] which lock already depends on the new lock.
> [ 20.507830]
> [ 20.507832]
> [ 20.507832] the existing dependency chain (in reverse order) is:
> [ 20.507837]
> [ 20.507837] -> #4 (&policy->rwsem){+.+.+.}:
> [ 20.507844] [<c00000000082385c>] .down_write+0x6c/0x110
> [ 20.507849] [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0
> [ 20.507855] [<c0000000004d76d8>] .subsys_interface_register+0xb8/0x110
> [ 20.507860] [<c000000000689bb0>] .cpufreq_register_driver+0x1d0/0x250
> [ 20.507866] [<c000000000b4f8f4>] .g5_cpufreq_init+0x9cc/0xa28
> [ 20.507872] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
> [ 20.507878] [<c000000000b0f86c>] .kernel_init_freeable+0x1ac/0x28c
> [ 20.507883] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.507887] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64
> [ 20.507894]
> [ 20.507894] -> #3 (subsys mutex#2){+.+.+.}:
> [ 20.507899] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
> [ 20.507903] [<c0000000004d7f24>] .bus_probe_device+0x44/0xe0
> [ 20.507907] [<c0000000004d5208>] .device_add+0x508/0x730
> [ 20.507911] [<c0000000004dd528>] .register_cpu+0x118/0x190
> [ 20.507916] [<c000000000b14450>] .topology_init+0x148/0x248
> [ 20.507921] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
> [ 20.507925] [<c000000000b0f86c>] .kernel_init_freeable+0x1ac/0x28c
> [ 20.507929] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.507934] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64
> [ 20.507939]
> [ 20.507939] -> #2 (cpu_add_remove_lock){+.+.+.}:
> [ 20.507944] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
> [ 20.507950] [<c000000000087a9c>] .register_cpu_notifier+0x2c/0x70
> [ 20.507955] [<c000000000b267e0>] .spawn_ksoftirqd+0x18/0x4c
> [ 20.507959] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
> [ 20.507964] [<c000000000b0f770>] .kernel_init_freeable+0xb0/0x28c
> [ 20.507968] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.507972] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64
> [ 20.507978]
> [ 20.507978] -> #1 (&host->mutex){+.+.+.}:
> [ 20.507982] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
> [ 20.507987] [<c0000000000527e8>] .kw_i2c_open+0x18/0x30
> [ 20.507991] [<c000000000052894>] .pmac_i2c_open+0x94/0x100
> [ 20.507995] [<c000000000b220a0>] .smp_core99_probe+0x260/0x410
> [ 20.507999] [<c000000000b185bc>] .smp_prepare_cpus+0x280/0x2ac
> [ 20.508003] [<c000000000b0f748>] .kernel_init_freeable+0x88/0x28c
> [ 20.508008] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.508012] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64
> [ 20.508018]
> [ 20.508018] -> #0 (&bus->mutex){+.+.+.}:
> [ 20.508023] [<c0000000000ed5b4>] .lock_acquire+0x84/0x100
> [ 20.508027] [<c000000000820448>] .mutex_lock_nested+0xa8/0x590
> [ 20.508032] [<c000000000052830>] .pmac_i2c_open+0x30/0x100
> [ 20.508037] [<c000000000052e14>] .pmac_i2c_do_begin+0x34/0x120
> [ 20.508040] [<c000000000056bc0>] .pmf_call_one+0x50/0xd0
> [ 20.508045] [<c00000000068ff1c>] .g5_pfunc_switch_volt+0x2c/0xc0
> [ 20.508050] [<c00000000068fecc>] .g5_pfunc_switch_freq+0x1cc/0x1f0
> [ 20.508054] [<c00000000068fc2c>] .g5_cpufreq_target+0x2c/0x40
> [ 20.508058] [<c0000000006873ec>] .__cpufreq_driver_target+0x23c/0x840
> [ 20.508062] [<c00000000068c798>] .cpufreq_gov_performance_limits+0x18/0x30
> [ 20.508067] [<c00000000068915c>] .cpufreq_start_governor+0xac/0x100
> [ 20.508071] [<c00000000068a788>] .cpufreq_set_policy+0x208/0x260
> [ 20.508076] [<c00000000068abdc>] .cpufreq_init_policy+0x6c/0xb0
> [ 20.508081] [<c00000000068ae70>] .cpufreq_online+0x250/0x9d0
> [ 20.508085] [<c0000000004d76d8>] .subsys_interface_register+0xb8/0x110
> [ 20.508090] [<c000000000689bb0>] .cpufreq_register_driver+0x1d0/0x250
> [ 20.508094] [<c000000000b4f8f4>] .g5_cpufreq_init+0x9cc/0xa28
> [ 20.508099] [<c00000000000a98c>] .do_one_initcall+0x5c/0x1d0
> [ 20.508103] [<c000000000b0f86c>] .kernel_init_freeable+0x1ac/0x28c
> [ 20.508107] [<c00000000000b3bc>] .kernel_init+0x1c/0x140
> [ 20.508112] [<c0000000000098f4>] .ret_from_kernel_thread+0x58/0x64
> [ 20.508113]
> [ 20.508113] other info that might help us debug this:
> [ 20.508113]
> [ 20.508121] Chain exists of:
> [ 20.508121] &bus->mutex --> subsys mutex#2 --> &policy->rwsem
> [ 20.508121]
> [ 20.508123] Possible unsafe locking scenario:
> [ 20.508123]
> [ 20.508124] CPU0 CPU1
> [ 20.508125] ---- ----
> [ 20.508128] lock(&policy->rwsem);
> [ 20.508132] lock(subsys mutex#2);
> [ 20.508135] lock(&policy->rwsem);
> [ 20.508138] lock(&bus->mutex);
> [ 20.508139]
> [ 20.508139] *** DEADLOCK ***
> [ 20.508139]
> [ 20.508141] 3 locks held by swapper/0/1:
> [ 20.508150] #0: (cpu_hotplug.lock){++++++}, at: [<c000000000087838>] .get_online_cpus+0x48/0xc0
> [ 20.508159] #1: (subsys mutex#2){+.+.+.}, at: [<c0000000004d7670>] .subsys_interface_register+0x50/0x110
> [ 20.508168] #2: (&policy->rwsem){+.+.+.}, at: [<c00000000068adcc>] .cpufreq_online+0x1ac/0x9d0
> [ 20.508169]
> [ 20.508169] stack backtrace:
> [ 20.508173] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.8.0-rc7-00037-gd2ffb01 #21
> [ 20.508175] Call Trace:
> [ 20.508180] [c0000000790c2b90] [c00000000082cc70] .dump_stack+0xe0/0x14c (unreliable)
> [ 20.508184] [c0000000790c2c20] [c000000000828c88] .print_circular_bug+0x350/0x388
> [ 20.508188] [c0000000790c2cd0] [c0000000000ecb0c] .__lock_acquire+0x196c/0x1d30
> [ 20.508192] [c0000000790c2e50] [c0000000000ed5b4] .lock_acquire+0x84/0x100
> [ 20.508196] [c0000000790c2f20] [c000000000820448] .mutex_lock_nested+0xa8/0x590
> [ 20.508201] [c0000000790c3030] [c000000000052830] .pmac_i2c_open+0x30/0x100
> [ 20.508206] [c0000000790c30c0] [c000000000052e14] .pmac_i2c_do_begin+0x34/0x120
> [ 20.508209] [c0000000790c3150] [c000000000056bc0] .pmf_call_one+0x50/0xd0
> [ 20.508213] [c0000000790c31e0] [c00000000068ff1c] .g5_pfunc_switch_volt+0x2c/0xc0
> [ 20.508217] [c0000000790c3250] [c00000000068fecc] .g5_pfunc_switch_freq+0x1cc/0x1f0
> [ 20.508221] [c0000000790c3320] [c00000000068fc2c] .g5_cpufreq_target+0x2c/0x40
> [ 20.508226] [c0000000790c3390] [c0000000006873ec] .__cpufreq_driver_target+0x23c/0x840
> [ 20.508230] [c0000000790c3440] [c00000000068c798] .cpufreq_gov_performance_limits+0x18/0x30
> [ 20.508235] [c0000000790c34b0] [c00000000068915c] .cpufreq_start_governor+0xac/0x100
> [ 20.508239] [c0000000790c3530] [c00000000068a788] .cpufreq_set_policy+0x208/0x260
> [ 20.508244] [c0000000790c35d0] [c00000000068abdc] .cpufreq_init_policy+0x6c/0xb0
> [ 20.508249] [c0000000790c3940] [c00000000068ae70] .cpufreq_online+0x250/0x9d0
> [ 20.508253] [c0000000790c3a30] [c0000000004d76d8] .subsys_interface_register+0xb8/0x110
> [ 20.508258] [c0000000790c3ad0] [c000000000689bb0] .cpufreq_register_driver+0x1d0/0x250
> [ 20.508262] [c0000000790c3b60] [c000000000b4f8f4] .g5_cpufreq_init+0x9cc/0xa28
> [ 20.508267] [c0000000790c3c20] [c00000000000a98c] .do_one_initcall+0x5c/0x1d0
> [ 20.508271] [c0000000790c3d00] [c000000000b0f86c] .kernel_init_freeable+0x1ac/0x28c
> [ 20.508276] [c0000000790c3db0] [c00000000000b3bc] .kernel_init+0x1c/0x140
> [ 20.508280] [c0000000790c3e30] [c0000000000098f4] .ret_from_kernel_thread+0x58/0x64
>
> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/9e607f72748ddc5620aeeb8d1f32f3
cheers
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2016-11-14 12:17 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-09-21 11:34 [PATCH] i2c_powermac: shut up lockdep warning Denis Kirjanov
2016-09-26 11:00 ` Denis Kirjanov
2016-09-26 21:03 ` Benjamin Herrenschmidt
2016-10-07 9:05 ` Denis Kirjanov
2016-10-10 5:35 ` Michael Ellerman
2016-10-10 7:25 ` Benjamin Herrenschmidt
2016-11-14 12:17 ` Michael Ellerman
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