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Message-ID: <alpine.LSU.2.20.1708031107230.30597@cbobk.fhfr.pm>
Date: Thu, 3 Aug 2017 11:10:14 +0200 (CEST)
From: Jiri Kosina <jikos@...nel.org>
To: Zhang Rui <rui.zhang@...el.com>,
Eduardo Valentin <edubezval@...il.com>,
Kalle Valo <kvalo@...eaurora.org>,
Sara Sharon <sara.sharon@...el.com>,
Johannes Berg <johannes.berg@...el.com>,
Emmanuel Grumbach <emmanuel.grumbach@...el.com>,
Luca Coelho <luciano.coelho@...el.com>
cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
Intel Linux Wireless <linuxwifi@...el.com>
Subject: Re: x86/thermal: AB-BA dependency between mvm->mutex and tz->lock
On Mon, 31 Jul 2017, Jiri Kosina wrote:
> Hi,
>
> booting current Linus' tree, I'm seeing lockdep splat (see the end of this
> mail).
>
> Apparently, there is AB-BA between tz->lock and mvm->mutex through the CPU
> hotplug lock.
>
> The obivous depency is: thermal_zone_get_temp() acquires tz->lock, and
> then calls iwl_mvm_tzone_get_temp() (through tz->ops->get_temp()
> callback), which acquires mvm->mutex
>
> The less obvious dependency is primarily caused by iwl_op_mode_mvm_start()
> allocating workqueue (#2 stacktrace) while holding mvm->mutex (which is
> broken, because that mutex is being taken also from CPU hotplug callback
> path, hence the AB-BA).
As the "central" part of the dependency is being added by iwlwifi driver
(_iwl_pcie_rx_init() allocating workqueue while holding
trans_pcie->mutex), I'm adding iwlwifi folks as well to CC.
>
> ======================================================
> WARNING: possible circular locking dependency detected
> 4.13.0-rc2-00110-g0b5477d #347 Not tainted
> ------------------------------------------------------
> modprobe/881 is trying to acquire lock:
> (&mvm->mutex){+.+.+.}, at: [<ffffffffc0c504d2>] iwl_mvm_tzone_get_temp+0x32/0x80 [iwlmvm]
>
> but task is already holding lock:
> (&tz->lock){+.+.+.}, at: [<ffffffff926a9351>] thermal_zone_get_temp+0x41/0x70
>
> which lock already depends on the new lock.
>
>
> the existing dependency chain (in reverse order) is:
>
> -> #5 (&tz->lock){+.+.+.}:
> lock_acquire+0xbd/0x220
> __mutex_lock+0x6e/0x900
> mutex_lock_nested+0x1b/0x20
> thermal_zone_get_temp+0x41/0x70
> thermal_zone_device_update+0x3c/0x280
> thermal_zone_device_register+0x3b8/0x610
> pkg_thermal_cpu_online+0x20b/0x284 [x86_pkg_temp_thermal]
> cpuhp_invoke_callback+0xac/0x900
> cpuhp_thread_fun+0x79/0x160
> smpboot_thread_fn+0x156/0x220
> kthread+0x114/0x150
> ret_from_fork+0x2a/0x40
>
> -> #4 (cpuhp_state){+.+.+.}:
> lock_acquire+0xbd/0x220
> cpuhp_issue_call+0xea/0x170
> __cpuhp_setup_state_cpuslocked+0x12a/0x190
> __cpuhp_setup_state+0x46/0xc0
> page_writeback_init+0x43/0x67
> pagecache_init+0x39/0x3c
> start_kernel+0x45a/0x4ae
> x86_64_start_reservations+0x24/0x26
> x86_64_start_kernel+0x13d/0x14c
> verify_cpu+0x0/0xf1
>
> -> #3 (cpuhp_state_mutex){+.+.+.}:
> lock_acquire+0xbd/0x220
> __mutex_lock+0x6e/0x900
> mutex_lock_nested+0x1b/0x20
> __cpuhp_setup_state_cpuslocked+0x4f/0x190
> __cpuhp_setup_state+0x46/0xc0
> page_alloc_init+0x28/0x30
> start_kernel+0x186/0x4ae
> x86_64_start_reservations+0x24/0x26
> x86_64_start_kernel+0x13d/0x14c
> verify_cpu+0x0/0xf1
>
> -> #2 (cpu_hotplug_lock.rw_sem){++++++}:
> lock_acquire+0xbd/0x220
> cpus_read_lock+0x46/0x90
> apply_workqueue_attrs+0x17/0x50
> __alloc_workqueue_key+0x195/0x4d0
> _iwl_pcie_rx_init+0x384/0x390 [iwlwifi]
> iwl_pcie_rx_init+0x1e/0x380 [iwlwifi]
> iwl_trans_pcie_start_fw+0x295/0x6f0 [iwlwifi]
> iwl_mvm_load_ucode_wait_alive+0xe7/0x390 [iwlmvm]
> iwl_run_init_mvm_ucode+0x84/0x320 [iwlmvm]
> iwl_op_mode_mvm_start+0x964/0xd30 [iwlmvm]
> _iwl_op_mode_start.isra.9+0x47/0xa0 [iwlwifi]
> iwl_opmode_register+0xaa/0xd0 [iwlwifi]
> iwl_mvm_init+0x37/0x1000 [iwlmvm]
> do_one_initcall+0x51/0x1a9
> do_init_module+0x60/0x20e
> load_module+0x203f/0x2b50
> SYSC_finit_module+0x96/0xd0
> SyS_finit_module+0xe/0x10
> entry_SYSCALL_64_fastpath+0x23/0xc2
>
> -> #1 (&trans_pcie->mutex){+.+.+.}:
> lock_acquire+0xbd/0x220
> __mutex_lock+0x6e/0x900
> mutex_lock_nested+0x1b/0x20
> iwl_trans_pcie_start_fw+0x130/0x6f0 [iwlwifi]
> iwl_mvm_load_ucode_wait_alive+0xe7/0x390 [iwlmvm]
> iwl_run_init_mvm_ucode+0x84/0x320 [iwlmvm]
> iwl_op_mode_mvm_start+0x964/0xd30 [iwlmvm]
> _iwl_op_mode_start.isra.9+0x47/0xa0 [iwlwifi]
> iwl_opmode_register+0xaa/0xd0 [iwlwifi]
> iwl_mvm_init+0x37/0x1000 [iwlmvm]
> do_one_initcall+0x51/0x1a9
> do_init_module+0x60/0x20e
> load_module+0x203f/0x2b50
> SYSC_finit_module+0x96/0xd0
> SyS_finit_module+0xe/0x10
> entry_SYSCALL_64_fastpath+0x23/0xc2
>
> -> #0 (&mvm->mutex){+.+.+.}:
> __lock_acquire+0x13e1/0x1400
> lock_acquire+0xbd/0x220
> __mutex_lock+0x6e/0x900
> mutex_lock_nested+0x1b/0x20
> iwl_mvm_tzone_get_temp+0x32/0x80 [iwlmvm]
> thermal_zone_get_temp+0x51/0x70
> thermal_zone_device_update+0x3c/0x280
> thermal_zone_device_register+0x3b8/0x610
> iwl_mvm_thermal_initialize+0x1d1/0x3a0 [iwlmvm]
> iwl_op_mode_mvm_start+0xa1d/0xd30 [iwlmvm]
> _iwl_op_mode_start.isra.9+0x47/0xa0 [iwlwifi]
> iwl_opmode_register+0xaa/0xd0 [iwlwifi]
> iwl_mvm_init+0x37/0x1000 [iwlmvm]
> do_one_initcall+0x51/0x1a9
> do_init_module+0x60/0x20e
> load_module+0x203f/0x2b50
> SYSC_finit_module+0x96/0xd0
> SyS_finit_module+0xe/0x10
> entry_SYSCALL_64_fastpath+0x23/0xc2
>
> other info that might help us debug this:
>
> Chain exists of:
> &mvm->mutex --> cpuhp_state --> &tz->lock
>
> Possible unsafe locking scenario:
>
> CPU0 CPU1
> ---- ----
> lock(&tz->lock);
> lock(cpuhp_state);
> lock(&tz->lock);
> lock(&mvm->mutex);
>
> *** DEADLOCK ***
>
> 2 locks held by modprobe/881:
> #0: (&iwlwifi_opmode_table_mtx){+.+.+.}, at: [<ffffffffc0aa2df4>] iwl_opmode_register+0x24/0xd0 [iwlwifi]
> #1: (&tz->lock){+.+.+.}, at: [<ffffffff926a9351>] thermal_zone_get_temp+0x41/0x70
>
> stack backtrace:
> CPU: 3 PID: 881 Comm: modprobe Not tainted 4.13.0-rc2-00110-g0b5477d #347
> Hardware name: LENOVO 20K5S22R00/20K5S22R00, BIOS R0IET38W (1.16 ) 05/31/2017
> Call Trace:
> dump_stack+0x85/0xc9
> print_circular_bug+0x1f9/0x207
> __lock_acquire+0x13e1/0x1400
> lock_acquire+0xbd/0x220
> ? iwl_mvm_tzone_get_temp+0x32/0x80 [iwlmvm]
> ? iwl_mvm_tzone_get_temp+0x32/0x80 [iwlmvm]
> __mutex_lock+0x6e/0x900
> ? iwl_mvm_tzone_get_temp+0x32/0x80 [iwlmvm]
> ? thermal_zone_get_temp+0x41/0x70
> ? iwl_mvm_tzone_get_temp+0x32/0x80 [iwlmvm]
> ? thermal_zone_get_temp+0x41/0x70
> ? find_held_lock+0x39/0xb0
> mutex_lock_nested+0x1b/0x20
> iwl_mvm_tzone_get_temp+0x32/0x80 [iwlmvm]
> thermal_zone_get_temp+0x51/0x70
> thermal_zone_device_update+0x3c/0x280
> thermal_zone_device_register+0x3b8/0x610
> iwl_mvm_thermal_initialize+0x1d1/0x3a0 [iwlmvm]
> iwl_op_mode_mvm_start+0xa1d/0xd30 [iwlmvm]
> _iwl_op_mode_start.isra.9+0x47/0xa0 [iwlwifi]
> iwl_opmode_register+0xaa/0xd0 [iwlwifi]
> iwl_mvm_init+0x37/0x1000 [iwlmvm]
> ? 0xffffffffc0c87000
> do_one_initcall+0x51/0x1a9
> ? rcu_read_lock_sched_held+0x98/0xa0
> ? kmem_cache_alloc_trace+0x2a5/0x340
> do_init_module+0x60/0x20e
> load_module+0x203f/0x2b50
> ? __symbol_put+0x50/0x50
> SYSC_finit_module+0x96/0xd0
> SyS_finit_module+0xe/0x10
> entry_SYSCALL_64_fastpath+0x23/0xc2
> RIP: 0033:0x7f2ef067cc89
> RSP: 002b:00007ffea2ea3d78 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
> RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f2ef067cc89
> RDX: 0000000000000000 RSI: 000000000041af06 RDI: 0000000000000001
> RBP: 0000000000000005 R08: 0000000000000000 R09: 000000000096b230
> R10: 0000000000000001 R11: 0000000000000246 R12: 00007ffea2ea2d80
> R13: 00007ffea2ea2d60 R14: 0000000000000005 R15: 000000000096f3c0
> thermal thermal_zone3: failed to read out thermal zone (-5)
>
>
> --
> Jiri Kosina
> SUSE Labs
>
--
Jiri Kosina
SUSE Labs
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