Hello,
I've found a suspicious circular locking dependency in i915 by lockdep. It seems main driver initialization thread and sub fbdev configuration thread take locks in different order implicitly. Please check it.
The lockdep report is here.
[ 4.254984] ====================================================== [ 4.254984] [ INFO: possible circular locking dependency detected ] [ 4.254985] 4.8.0-rc1+ #8 Not tainted [ 4.254985] ------------------------------------------------------- [ 4.254986] kworker/u16:1/72 is trying to acquire lock: [ 4.255001] (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffc02eafb0>] drm_modeset_lock_all+0x40/0x130 [drm] [ 4.255001] but task is already holding lock: [ 4.255005] ((fb_notifier_list).rwsem){++++.+}, at: [<ffffffff980b2ea5>] __blocking_notifier_call_chain+0x35/0x70 [ 4.255005] which lock already depends on the new lock.
[ 4.255005] the existing dependency chain (in reverse order) is: [ 4.255006] -> #1 ((fb_notifier_list).rwsem){++++.+}: [ 4.255009] [<ffffffff980e7a00>] lock_acquire+0x100/0x1f0 [ 4.255011] [<ffffffff988b29a9>] down_write+0x49/0x80 [ 4.255013] [<ffffffff980b3031>] blocking_notifier_chain_register+0x21/0xb0 [ 4.255015] [<ffffffff984c93c8>] fb_register_client+0x18/0x20 [ 4.255016] [<ffffffff984c8c1e>] backlight_device_register+0x12e/0x250 [ 4.255046] [<ffffffffc04e3842>] intel_backlight_device_register+0xa2/0x160 [i915] [ 4.255070] [<ffffffffc04b173e>] intel_connector_register+0xe/0x10 [i915] [ 4.255093] [<ffffffffc04cd5db>] intel_dp_connector_register+0x1b/0x80 [i915] [ 4.255102] [<ffffffffc02d943a>] drm_connector_register+0x4a/0x80 [drm] [ 4.255110] [<ffffffffc02ddbe6>] drm_modeset_register_all+0x1c6/0x260 [drm] [ 4.255116] [<ffffffffc02d4ba2>] drm_dev_register+0xc2/0xd0 [drm] [ 4.255135] [<ffffffffc04212f1>] i915_driver_load+0x771/0x1460 [i915] [ 4.255153] [<ffffffffc042c63f>] i915_pci_probe+0x4f/0x70 [i915] [ 4.255155] [<ffffffff98497905>] local_pci_probe+0x45/0xa0 [ 4.255157] [<ffffffff98498d11>] pci_device_probe+0xe1/0x130 [ 4.255159] [<ffffffff985ae5e4>] driver_probe_device+0x224/0x430 [ 4.255160] [<ffffffff985ae8d3>] __driver_attach+0xe3/0xf0 [ 4.255160] [<ffffffff985ac166>] bus_for_each_dev+0x66/0xa0 [ 4.255161] [<ffffffff985adcee>] driver_attach+0x1e/0x20 [ 4.255162] [<ffffffff985ad7d0>] bus_add_driver+0x200/0x270 [ 4.255164] [<ffffffff985af520>] driver_register+0x60/0xe0 [ 4.255165] [<ffffffff98497230>] __pci_register_driver+0x60/0x70 [ 4.255182] [<ffffffffc035f05b>] i915_init+0x5b/0x62 [i915] [ 4.255183] [<ffffffff9800217d>] do_one_initcall+0x3d/0x160 [ 4.255186] [<ffffffff981c6d8d>] do_init_module+0x5f/0x1f8 [ 4.255187] [<ffffffff9812fbdc>] load_module+0x246c/0x2bd0 [ 4.255188] [<ffffffff9813057c>] SYSC_finit_module+0xbc/0xf0 [ 4.255190] [<ffffffff981305ce>] SyS_finit_module+0xe/0x10 [ 4.255191] [<ffffffff988b5680>] entry_SYSCALL_64_fastpath+0x23/0xc1 [ 4.255192] -> #0 (&dev->mode_config.mutex){+.+.+.}: [ 4.255194] [<ffffffff980e732c>] __lock_acquire+0x125c/0x14b0 [ 4.255195] [<ffffffff980e7a00>] lock_acquire+0x100/0x1f0 [ 4.255197] [<ffffffff988b0889>] mutex_lock_nested+0x69/0x3b0 [ 4.255206] [<ffffffffc02eafb0>] drm_modeset_lock_all+0x40/0x130 [drm] [ 4.255212] [<ffffffffc03f877b>] drm_fb_helper_restore_fbdev_mode_unlocked+0x2b/0x80 [drm_kms_helper] [ 4.255217] [<ffffffffc03f87fd>] drm_fb_helper_set_par+0x2d/0x50 [drm_kms_helper] [ 4.255240] [<ffffffffc04c21da>] intel_fbdev_set_par+0x1a/0x60 [i915] [ 4.255242] [<ffffffff984c2f2f>] fbcon_init+0x57f/0x600 [ 4.255244] [<ffffffff98555026>] visual_init+0xd6/0x130 [ 4.255245] [<ffffffff98556831>] do_bind_con_driver+0x1c1/0x3a0 [ 4.255246] [<ffffffff98556d16>] do_take_over_console+0x116/0x180 [ 4.255247] [<ffffffff984beb67>] do_fbcon_takeover+0x57/0xb0 [ 4.255249] [<ffffffff984c39a8>] fbcon_event_notify+0x658/0x750 [ 4.255250] [<ffffffff980b2c1a>] notifier_call_chain+0x4a/0x70 [ 4.255251] [<ffffffff980b2ebd>] __blocking_notifier_call_chain+0x4d/0x70 [ 4.255253] [<ffffffff980b2ef6>] blocking_notifier_call_chain+0x16/0x20 [ 4.255254] [<ffffffff984c940b>] fb_notifier_call_chain+0x1b/0x20 [ 4.255255] [<ffffffff984cb6c1>] register_framebuffer+0x251/0x330 [ 4.255259] [<ffffffffc03f8a7f>] drm_fb_helper_initial_config+0x25f/0x3f0 [drm_kms_helper] [ 4.255282] [<ffffffffc04c3498>] intel_fbdev_initial_config+0x18/0x30 [i915] [ 4.255283] [<ffffffff980b4aa7>] async_run_entry_fn+0x37/0x150 [ 4.255284] [<ffffffff980aa9c8>] process_one_work+0x1e8/0x710 [ 4.255285] [<ffffffff980aaf3b>] worker_thread+0x4b/0x4f0 [ 4.255286] [<ffffffff980b193f>] kthread+0xef/0x110 [ 4.255287] [<ffffffff988b58cf>] ret_from_fork+0x1f/0x40 [ 4.255287] other info that might help us debug this:
[ 4.255288] Possible unsafe locking scenario:
[ 4.255288] CPU0 CPU1 [ 4.255288] ---- ---- [ 4.255289] lock((fb_notifier_list).rwsem); [ 4.255290] lock(&dev->mode_config.mutex); [ 4.255290] lock((fb_notifier_list).rwsem); [ 4.255291] lock(&dev->mode_config.mutex); [ 4.255291] *** DEADLOCK ***
And i915 related kconfigs are here: ---- CONFIG_DRM_I915=m CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT=y CONFIG_DRM_I915_USERPTR=y CONFIG_DRM_I915_GVT=y # CONFIG_DRM_I915_WERROR is not set # CONFIG_DRM_I915_DEBUG is not set ----
I've hit this on my DELL XPS15 which has skylake CPU/GPU.
Thanks,
On Sun, Aug 14, 2016 at 11:01:35PM +0900, Masami Hiramatsu wrote:
Hello,
I've found a suspicious circular locking dependency in i915 by lockdep. It seems main driver initialization thread and sub fbdev configuration thread take locks in different order implicitly. Please check it.
The lockdep report is here.
Should be fixed in 4.8-rc2, please confirm. -Daniel
[ 4.254984] ====================================================== [ 4.254984] [ INFO: possible circular locking dependency detected ] [ 4.254985] 4.8.0-rc1+ #8 Not tainted [ 4.254985] ------------------------------------------------------- [ 4.254986] kworker/u16:1/72 is trying to acquire lock: [ 4.255001] (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffc02eafb0>] drm_modeset_lock_all+0x40/0x130 [drm] [ 4.255001] but task is already holding lock: [ 4.255005] ((fb_notifier_list).rwsem){++++.+}, at: [<ffffffff980b2ea5>] __blocking_notifier_call_chain+0x35/0x70 [ 4.255005] which lock already depends on the new lock.
[ 4.255005] the existing dependency chain (in reverse order) is: [ 4.255006] -> #1 ((fb_notifier_list).rwsem){++++.+}: [ 4.255009] [<ffffffff980e7a00>] lock_acquire+0x100/0x1f0 [ 4.255011] [<ffffffff988b29a9>] down_write+0x49/0x80 [ 4.255013] [<ffffffff980b3031>] blocking_notifier_chain_register+0x21/0xb0 [ 4.255015] [<ffffffff984c93c8>] fb_register_client+0x18/0x20 [ 4.255016] [<ffffffff984c8c1e>] backlight_device_register+0x12e/0x250 [ 4.255046] [<ffffffffc04e3842>] intel_backlight_device_register+0xa2/0x160 [i915] [ 4.255070] [<ffffffffc04b173e>] intel_connector_register+0xe/0x10 [i915] [ 4.255093] [<ffffffffc04cd5db>] intel_dp_connector_register+0x1b/0x80 [i915] [ 4.255102] [<ffffffffc02d943a>] drm_connector_register+0x4a/0x80 [drm] [ 4.255110] [<ffffffffc02ddbe6>] drm_modeset_register_all+0x1c6/0x260 [drm] [ 4.255116] [<ffffffffc02d4ba2>] drm_dev_register+0xc2/0xd0 [drm] [ 4.255135] [<ffffffffc04212f1>] i915_driver_load+0x771/0x1460 [i915] [ 4.255153] [<ffffffffc042c63f>] i915_pci_probe+0x4f/0x70 [i915] [ 4.255155] [<ffffffff98497905>] local_pci_probe+0x45/0xa0 [ 4.255157] [<ffffffff98498d11>] pci_device_probe+0xe1/0x130 [ 4.255159] [<ffffffff985ae5e4>] driver_probe_device+0x224/0x430 [ 4.255160] [<ffffffff985ae8d3>] __driver_attach+0xe3/0xf0 [ 4.255160] [<ffffffff985ac166>] bus_for_each_dev+0x66/0xa0 [ 4.255161] [<ffffffff985adcee>] driver_attach+0x1e/0x20 [ 4.255162] [<ffffffff985ad7d0>] bus_add_driver+0x200/0x270 [ 4.255164] [<ffffffff985af520>] driver_register+0x60/0xe0 [ 4.255165] [<ffffffff98497230>] __pci_register_driver+0x60/0x70 [ 4.255182] [<ffffffffc035f05b>] i915_init+0x5b/0x62 [i915] [ 4.255183] [<ffffffff9800217d>] do_one_initcall+0x3d/0x160 [ 4.255186] [<ffffffff981c6d8d>] do_init_module+0x5f/0x1f8 [ 4.255187] [<ffffffff9812fbdc>] load_module+0x246c/0x2bd0 [ 4.255188] [<ffffffff9813057c>] SYSC_finit_module+0xbc/0xf0 [ 4.255190] [<ffffffff981305ce>] SyS_finit_module+0xe/0x10 [ 4.255191] [<ffffffff988b5680>] entry_SYSCALL_64_fastpath+0x23/0xc1 [ 4.255192] -> #0 (&dev->mode_config.mutex){+.+.+.}: [ 4.255194] [<ffffffff980e732c>] __lock_acquire+0x125c/0x14b0 [ 4.255195] [<ffffffff980e7a00>] lock_acquire+0x100/0x1f0 [ 4.255197] [<ffffffff988b0889>] mutex_lock_nested+0x69/0x3b0 [ 4.255206] [<ffffffffc02eafb0>] drm_modeset_lock_all+0x40/0x130 [drm] [ 4.255212] [<ffffffffc03f877b>] drm_fb_helper_restore_fbdev_mode_unlocked+0x2b/0x80 [drm_kms_helper] [ 4.255217] [<ffffffffc03f87fd>] drm_fb_helper_set_par+0x2d/0x50 [drm_kms_helper] [ 4.255240] [<ffffffffc04c21da>] intel_fbdev_set_par+0x1a/0x60 [i915] [ 4.255242] [<ffffffff984c2f2f>] fbcon_init+0x57f/0x600 [ 4.255244] [<ffffffff98555026>] visual_init+0xd6/0x130 [ 4.255245] [<ffffffff98556831>] do_bind_con_driver+0x1c1/0x3a0 [ 4.255246] [<ffffffff98556d16>] do_take_over_console+0x116/0x180 [ 4.255247] [<ffffffff984beb67>] do_fbcon_takeover+0x57/0xb0 [ 4.255249] [<ffffffff984c39a8>] fbcon_event_notify+0x658/0x750 [ 4.255250] [<ffffffff980b2c1a>] notifier_call_chain+0x4a/0x70 [ 4.255251] [<ffffffff980b2ebd>] __blocking_notifier_call_chain+0x4d/0x70 [ 4.255253] [<ffffffff980b2ef6>] blocking_notifier_call_chain+0x16/0x20 [ 4.255254] [<ffffffff984c940b>] fb_notifier_call_chain+0x1b/0x20 [ 4.255255] [<ffffffff984cb6c1>] register_framebuffer+0x251/0x330 [ 4.255259] [<ffffffffc03f8a7f>] drm_fb_helper_initial_config+0x25f/0x3f0 [drm_kms_helper] [ 4.255282] [<ffffffffc04c3498>] intel_fbdev_initial_config+0x18/0x30 [i915] [ 4.255283] [<ffffffff980b4aa7>] async_run_entry_fn+0x37/0x150 [ 4.255284] [<ffffffff980aa9c8>] process_one_work+0x1e8/0x710 [ 4.255285] [<ffffffff980aaf3b>] worker_thread+0x4b/0x4f0 [ 4.255286] [<ffffffff980b193f>] kthread+0xef/0x110 [ 4.255287] [<ffffffff988b58cf>] ret_from_fork+0x1f/0x40 [ 4.255287] other info that might help us debug this:
[ 4.255288] Possible unsafe locking scenario:
[ 4.255288] CPU0 CPU1 [ 4.255288] ---- ---- [ 4.255289] lock((fb_notifier_list).rwsem); [ 4.255290] lock(&dev->mode_config.mutex); [ 4.255290] lock((fb_notifier_list).rwsem); [ 4.255291] lock(&dev->mode_config.mutex); [ 4.255291] *** DEADLOCK ***
And i915 related kconfigs are here:
CONFIG_DRM_I915=m CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT=y CONFIG_DRM_I915_USERPTR=y CONFIG_DRM_I915_GVT=y # CONFIG_DRM_I915_WERROR is not set
# CONFIG_DRM_I915_DEBUG is not set
I've hit this on my DELL XPS15 which has skylake CPU/GPU.
Thanks,
-- Masami Hiramatsu mhiramat@kernel.org _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
On Mon, 15 Aug 2016 08:39:29 +0200 Daniel Vetter daniel@ffwll.ch wrote:
On Sun, Aug 14, 2016 at 11:01:35PM +0900, Masami Hiramatsu wrote:
Hello,
I've found a suspicious circular locking dependency in i915 by lockdep. It seems main driver initialization thread and sub fbdev configuration thread take locks in different order implicitly. Please check it.
The lockdep report is here.
Should be fixed in 4.8-rc2, please confirm.
Thanks! I've confirmed this has fixed on 4.8-rc2.
Regards,
-Daniel
[ 4.254984] ====================================================== [ 4.254984] [ INFO: possible circular locking dependency detected ] [ 4.254985] 4.8.0-rc1+ #8 Not tainted [ 4.254985] ------------------------------------------------------- [ 4.254986] kworker/u16:1/72 is trying to acquire lock: [ 4.255001] (&dev->mode_config.mutex){+.+.+.}, at: [<ffffffffc02eafb0>] drm_modeset_lock_all+0x40/0x130 [drm] [ 4.255001] but task is already holding lock: [ 4.255005] ((fb_notifier_list).rwsem){++++.+}, at: [<ffffffff980b2ea5>] __blocking_notifier_call_chain+0x35/0x70 [ 4.255005] which lock already depends on the new lock.
[ 4.255005] the existing dependency chain (in reverse order) is: [ 4.255006] -> #1 ((fb_notifier_list).rwsem){++++.+}: [ 4.255009] [<ffffffff980e7a00>] lock_acquire+0x100/0x1f0 [ 4.255011] [<ffffffff988b29a9>] down_write+0x49/0x80 [ 4.255013] [<ffffffff980b3031>] blocking_notifier_chain_register+0x21/0xb0 [ 4.255015] [<ffffffff984c93c8>] fb_register_client+0x18/0x20 [ 4.255016] [<ffffffff984c8c1e>] backlight_device_register+0x12e/0x250 [ 4.255046] [<ffffffffc04e3842>] intel_backlight_device_register+0xa2/0x160 [i915] [ 4.255070] [<ffffffffc04b173e>] intel_connector_register+0xe/0x10 [i915] [ 4.255093] [<ffffffffc04cd5db>] intel_dp_connector_register+0x1b/0x80 [i915] [ 4.255102] [<ffffffffc02d943a>] drm_connector_register+0x4a/0x80 [drm] [ 4.255110] [<ffffffffc02ddbe6>] drm_modeset_register_all+0x1c6/0x260 [drm] [ 4.255116] [<ffffffffc02d4ba2>] drm_dev_register+0xc2/0xd0 [drm] [ 4.255135] [<ffffffffc04212f1>] i915_driver_load+0x771/0x1460 [i915] [ 4.255153] [<ffffffffc042c63f>] i915_pci_probe+0x4f/0x70 [i915] [ 4.255155] [<ffffffff98497905>] local_pci_probe+0x45/0xa0 [ 4.255157] [<ffffffff98498d11>] pci_device_probe+0xe1/0x130 [ 4.255159] [<ffffffff985ae5e4>] driver_probe_device+0x224/0x430 [ 4.255160] [<ffffffff985ae8d3>] __driver_attach+0xe3/0xf0 [ 4.255160] [<ffffffff985ac166>] bus_for_each_dev+0x66/0xa0 [ 4.255161] [<ffffffff985adcee>] driver_attach+0x1e/0x20 [ 4.255162] [<ffffffff985ad7d0>] bus_add_driver+0x200/0x270 [ 4.255164] [<ffffffff985af520>] driver_register+0x60/0xe0 [ 4.255165] [<ffffffff98497230>] __pci_register_driver+0x60/0x70 [ 4.255182] [<ffffffffc035f05b>] i915_init+0x5b/0x62 [i915] [ 4.255183] [<ffffffff9800217d>] do_one_initcall+0x3d/0x160 [ 4.255186] [<ffffffff981c6d8d>] do_init_module+0x5f/0x1f8 [ 4.255187] [<ffffffff9812fbdc>] load_module+0x246c/0x2bd0 [ 4.255188] [<ffffffff9813057c>] SYSC_finit_module+0xbc/0xf0 [ 4.255190] [<ffffffff981305ce>] SyS_finit_module+0xe/0x10 [ 4.255191] [<ffffffff988b5680>] entry_SYSCALL_64_fastpath+0x23/0xc1 [ 4.255192] -> #0 (&dev->mode_config.mutex){+.+.+.}: [ 4.255194] [<ffffffff980e732c>] __lock_acquire+0x125c/0x14b0 [ 4.255195] [<ffffffff980e7a00>] lock_acquire+0x100/0x1f0 [ 4.255197] [<ffffffff988b0889>] mutex_lock_nested+0x69/0x3b0 [ 4.255206] [<ffffffffc02eafb0>] drm_modeset_lock_all+0x40/0x130 [drm] [ 4.255212] [<ffffffffc03f877b>] drm_fb_helper_restore_fbdev_mode_unlocked+0x2b/0x80 [drm_kms_helper] [ 4.255217] [<ffffffffc03f87fd>] drm_fb_helper_set_par+0x2d/0x50 [drm_kms_helper] [ 4.255240] [<ffffffffc04c21da>] intel_fbdev_set_par+0x1a/0x60 [i915] [ 4.255242] [<ffffffff984c2f2f>] fbcon_init+0x57f/0x600 [ 4.255244] [<ffffffff98555026>] visual_init+0xd6/0x130 [ 4.255245] [<ffffffff98556831>] do_bind_con_driver+0x1c1/0x3a0 [ 4.255246] [<ffffffff98556d16>] do_take_over_console+0x116/0x180 [ 4.255247] [<ffffffff984beb67>] do_fbcon_takeover+0x57/0xb0 [ 4.255249] [<ffffffff984c39a8>] fbcon_event_notify+0x658/0x750 [ 4.255250] [<ffffffff980b2c1a>] notifier_call_chain+0x4a/0x70 [ 4.255251] [<ffffffff980b2ebd>] __blocking_notifier_call_chain+0x4d/0x70 [ 4.255253] [<ffffffff980b2ef6>] blocking_notifier_call_chain+0x16/0x20 [ 4.255254] [<ffffffff984c940b>] fb_notifier_call_chain+0x1b/0x20 [ 4.255255] [<ffffffff984cb6c1>] register_framebuffer+0x251/0x330 [ 4.255259] [<ffffffffc03f8a7f>] drm_fb_helper_initial_config+0x25f/0x3f0 [drm_kms_helper] [ 4.255282] [<ffffffffc04c3498>] intel_fbdev_initial_config+0x18/0x30 [i915] [ 4.255283] [<ffffffff980b4aa7>] async_run_entry_fn+0x37/0x150 [ 4.255284] [<ffffffff980aa9c8>] process_one_work+0x1e8/0x710 [ 4.255285] [<ffffffff980aaf3b>] worker_thread+0x4b/0x4f0 [ 4.255286] [<ffffffff980b193f>] kthread+0xef/0x110 [ 4.255287] [<ffffffff988b58cf>] ret_from_fork+0x1f/0x40 [ 4.255287] other info that might help us debug this:
[ 4.255288] Possible unsafe locking scenario:
[ 4.255288] CPU0 CPU1 [ 4.255288] ---- ---- [ 4.255289] lock((fb_notifier_list).rwsem); [ 4.255290] lock(&dev->mode_config.mutex); [ 4.255290] lock((fb_notifier_list).rwsem); [ 4.255291] lock(&dev->mode_config.mutex); [ 4.255291] *** DEADLOCK ***
And i915 related kconfigs are here:
CONFIG_DRM_I915=m CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT=y CONFIG_DRM_I915_USERPTR=y CONFIG_DRM_I915_GVT=y # CONFIG_DRM_I915_WERROR is not set
# CONFIG_DRM_I915_DEBUG is not set
I've hit this on my DELL XPS15 which has skylake CPU/GPU.
Thanks,
-- Masami Hiramatsu mhiramat@kernel.org _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
-- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
dri-devel@lists.freedesktop.org
-
Daniel Vetter -
Masami Hiramatsu