Re: circular locking warning during suspend

From: Daniel Vetter
Date: Thu Jan 24 2013 - 14:58:24 EST

On Thu, Jan 24, 2013 at 6:34 PM, Johannes Berg
<johannes@xxxxxxxxxxxxxxxx> wrote:
> Hi,
>
> I didn't find this reported, but maybe it has been, I didn't search for
> too long. I'm using 3.8.0-rc4 (plus wireless bits), and lockdep is
> unhappy. Note that I am booting with "no_console_suspend".

Patches for the know issues around consolo_lock vs fbdev_notifier are in -mm:

http://ozlabs.org/~akpm/mmots/broken-out/fb-rework-locking-to-fix-lock-ordering-on-takeover.patch
http://ozlabs.org/~akpm/mmots/broken-out/fb-yet-another-band-aid-
for-fixing-lockdep-mess.patch

Unfortunately the patches seem to be stuck there for now despite quite
a few reports about this (including seemingly relevant background
noise about hangs in distro bugzillas).
-Daniel

>
> [ 73.320586] ======================================================
> [ 73.320587] [ INFO: possible circular locking dependency detected ]
> [ 73.320592] 3.8.0-rc4-wl-67484-g04fa847 #106 Tainted: G W
> [ 73.320594] -------------------------------------------------------
> [ 73.320597] kworker/u:9/2574 is trying to acquire lock:
> [ 73.320614] ((fb_notifier_list).rwsem){.+.+.+}, at: [<ffffffff8106f94a>] __blocking_notifier_call_chain+0x5a/0xd0
> [ 73.320616]
> [ 73.320616] but task is already holding lock:
> [ 73.320627] (console_lock){+.+.+.}, at: [<ffffffff81323c80>] i915_drm_freeze+0x90/0xe0
> [ 73.320628]
> [ 73.320628] which lock already depends on the new lock.
> [ 73.320628]
> [ 73.320629]
> [ 73.320629] the existing dependency chain (in reverse order) is:
> [ 73.320635]
> [ 73.320635] -> #1 (console_lock){+.+.+.}:
> [ 73.320642] [<ffffffff810a13e6>] lock_acquire+0x96/0x1e0
> [ 73.320647] [<ffffffff8103bda7>] console_lock+0x77/0x80
> [ 73.320654] [<ffffffff812e2fda>] register_con_driver+0x3a/0x150
> [ 73.320660] [<ffffffff812e4b4f>] take_over_console+0x2f/0x70
> [ 73.320666] [<ffffffff81287d53>] fbcon_takeover+0x63/0xc0
> [ 73.320671] [<ffffffff8128baa5>] fbcon_event_notify+0x615/0x720
> [ 73.320677] [<ffffffff814b56ed>] notifier_call_chain+0x5d/0x110
> [ 73.320683] [<ffffffff8106f964>] __blocking_notifier_call_chain+0x74/0xd0
> [ 73.320689] [<ffffffff8106f9d6>] blocking_notifier_call_chain+0x16/0x20
> [ 73.320695] [<ffffffff8127ce6b>] fb_notifier_call_chain+0x1b/0x20
> [ 73.320700] [<ffffffff8127e625>] register_framebuffer+0x1c5/0x300
> [ 73.320707] [<ffffffff813021bc>] drm_fb_helper_single_fb_probe+0x1fc/0x330
> [ 73.320712] [<ffffffff813024d2>] drm_fb_helper_initial_config+0x1e2/0x250
> [ 73.320718] [<ffffffff81374cea>] intel_fbdev_init+0x8a/0xc0
> [ 73.320724] [<ffffffff81329527>] i915_driver_load+0xbc7/0xe00
> [ 73.320730] [<ffffffff81311bbe>] drm_get_pci_dev+0x18e/0x2d0
> [ 73.320735] [<ffffffff8132407b>] i915_pci_probe+0x3b/0x90
> [ 73.320741] [<ffffffff8126f036>] pci_device_probe+0xa6/0xf0
> [ 73.320747] [<ffffffff8138765c>] driver_probe_device+0x7c/0x240
> [ 73.320752] [<ffffffff813878bc>] __driver_attach+0x9c/0xa0
> [ 73.320757] [<ffffffff813857d6>] bus_for_each_dev+0x56/0x90
> [ 73.320762] [<ffffffff8138711e>] driver_attach+0x1e/0x20
> [ 73.320767] [<ffffffff81386cd8>] bus_add_driver+0x1a8/0x270
> [ 73.320772] [<ffffffff81387fa8>] driver_register+0x78/0x160
> [ 73.320777] [<ffffffff8126de65>] __pci_register_driver+0x65/0x70
> [ 73.320782] [<ffffffff81311e17>] drm_pci_init+0x117/0x130
> [ 73.320789] [<ffffffff81c81871>] i915_init+0x66/0x68
> [ 73.320796] [<ffffffff810002f2>] do_one_initcall+0x122/0x170
> [ 73.320801] [<ffffffff8149af8c>] kernel_init+0x13c/0x2b0
> [ 73.320807] [<ffffffff814b9d5c>] ret_from_fork+0x7c/0xb0
> [ 73.320813]
> [ 73.320813] -> #0 ((fb_notifier_list).rwsem){.+.+.+}:
> [ 73.320818] [<ffffffff810a0c1e>] __lock_acquire+0x1aee/0x1be0
> [ 73.320823] [<ffffffff810a13e6>] lock_acquire+0x96/0x1e0
> [ 73.320829] [<ffffffff814af21e>] down_read+0x4e/0x98
> [ 73.320835] [<ffffffff8106f94a>] __blocking_notifier_call_chain+0x5a/0xd0
> [ 73.320841] [<ffffffff8106f9d6>] blocking_notifier_call_chain+0x16/0x20
> [ 73.320846] [<ffffffff8127ce6b>] fb_notifier_call_chain+0x1b/0x20
> [ 73.320851] [<ffffffff8127d5de>] fb_set_suspend+0x4e/0x60
> [ 73.320856] [<ffffffff81374e65>] intel_fbdev_set_suspend+0x25/0x30
> [ 73.320862] [<ffffffff81323c8d>] i915_drm_freeze+0x9d/0xe0
> [ 73.320867] [<ffffffff813242ea>] i915_pm_suspend+0x4a/0xa0
> [ 73.320872] [<ffffffff8126e2b4>] pci_pm_suspend+0x74/0x140
> [ 73.320878] [<ffffffff8138f12c>] dpm_run_callback.isra.3+0x3c/0x80
> [ 73.320883] [<ffffffff8138f255>] __device_suspend+0xe5/0x200
> [ 73.320888] [<ffffffff8138fa1f>] async_suspend+0x1f/0xa0
> [ 73.320892] [<ffffffff81070762>] async_run_entry_fn+0x92/0x1c0
> [ 73.320898] [<ffffffff81060198>] process_one_work+0x208/0x750
> [ 73.320903] [<ffffffff81060ad0>] worker_thread+0x160/0x450
> [ 73.320909] [<ffffffff810676b2>] kthread+0xf2/0x100
> [ 73.320915] [<ffffffff814b9d5c>] ret_from_fork+0x7c/0xb0
> [ 73.320917]
> [ 73.320917] other info that might help us debug this:
> [ 73.320917]
> [ 73.320918] Possible unsafe locking scenario:
> [ 73.320918]
> [ 73.320919] CPU0 CPU1
> [ 73.320921] ---- ----
> [ 73.320924] lock(console_lock);
> [ 73.320927] lock((fb_notifier_list).rwsem);
> [ 73.320931] lock(console_lock);
> [ 73.320934] lock((fb_notifier_list).rwsem);
> [ 73.320935]
> [ 73.320935] *** DEADLOCK ***
> [ 73.320935]
> [ 73.320937] 4 locks held by kworker/u:9/2574:
> [ 73.320947] #0: (events_unbound){.+.+.+}, at: [<ffffffff81060127>] process_one_work+0x197/0x750
> [ 73.320955] #1: ((&entry->work)){+.+.+.}, at: [<ffffffff81060127>] process_one_work+0x197/0x750
> [ 73.320964] #2: (&__lockdep_no_validate__){......}, at: [<ffffffff8138f228>] __device_suspend+0xb8/0x200
> [ 73.320974] #3: (console_lock){+.+.+.}, at: [<ffffffff81323c80>] i915_drm_freeze+0x90/0xe0
> [ 73.320975]
> [ 73.320975] stack backtrace:
> [ 73.320979] Pid: 2574, comm: kworker/u:9 Tainted: G W 3.8.0-rc4-wl-67484-g04fa847 #106
> [ 73.320981] Call Trace:
> [ 73.320990] [<ffffffff814a8c8c>] print_circular_bug+0x1fc/0x20e
> [ 73.320996] [<ffffffff810a0c1e>] __lock_acquire+0x1aee/0x1be0
> [ 73.321016] [<ffffffff810a13e6>] lock_acquire+0x96/0x1e0
> [ 73.321029] [<ffffffff814af21e>] down_read+0x4e/0x98
> [ 73.321041] [<ffffffff8106f94a>] __blocking_notifier_call_chain+0x5a/0xd0
> [ 73.321047] [<ffffffff8106f9d6>] blocking_notifier_call_chain+0x16/0x20
> [ 73.321053] [<ffffffff8127ce6b>] fb_notifier_call_chain+0x1b/0x20
> [ 73.321058] [<ffffffff8127d5de>] fb_set_suspend+0x4e/0x60
> [ 73.321063] [<ffffffff81374e65>] intel_fbdev_set_suspend+0x25/0x30
> [ 73.321069] [<ffffffff81323c8d>] i915_drm_freeze+0x9d/0xe0
> [ 73.321075] [<ffffffff813242ea>] i915_pm_suspend+0x4a/0xa0
> [ 73.321080] [<ffffffff8126e2b4>] pci_pm_suspend+0x74/0x140
> [ 73.321091] [<ffffffff8138f12c>] dpm_run_callback.isra.3+0x3c/0x80
> [ 73.321096] [<ffffffff8138f255>] __device_suspend+0xe5/0x200
> [ 73.321102] [<ffffffff8138fa1f>] async_suspend+0x1f/0xa0
> [ 73.321107] [<ffffffff81070762>] async_run_entry_fn+0x92/0x1c0
> [ 73.321113] [<ffffffff81060198>] process_one_work+0x208/0x750
> [ 73.321142] [<ffffffff81060ad0>] worker_thread+0x160/0x450
> [ 73.321153] [<ffffffff810676b2>] kthread+0xf2/0x100
> [ 73.321173] [<ffffffff814b9d5c>] ret_from_fork+0x7c/0xb0
>
> johannes
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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