On Tue, 3 Dec 2019 at 10:13, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote:
>
> Some machines require ACPI for runtime resume, and ACPI is quite kmalloc
> happy. We cannot handle kmalloc from inside the vm->mutex, as they are
> used by the shrinker, and so we must ensure the global runtime-pm is
> awake prior to unbinding to avoid the potential inversion.
>
> <4> [57.121748] ======================================================
> <4> [57.121750] WARNING: possible circular locking dependency detected
> <4> [57.121753] 5.4.0-rc8-CI-CI_DRM_7466+ #1 Tainted: G U
> <4> [57.121754] ------------------------------------------------------
> <4> [57.121756] i915_pm_rpm/1105 is trying to acquire lock:
> <4> [57.121758] ffffffff82263a40 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.117+0x0/0x30
> <4> [57.121766]
> but task is already holding lock:
> <4> [57.121768] ffff888475a593c0 (&vm->mutex){+.+.}, at: i915_vma_unbind+0x21/0x50 [i915]
> <4> [57.121868]
> which lock already depends on the new lock.
>
> <4> [57.121869]
> the existing dependency chain (in reverse order) is:
> <4> [57.121871]
> -> #1 (&vm->mutex){+.+.}:
> <4> [57.121951] i915_gem_shrinker_taints_mutex+0xa2/0xd0 [i915]
> <4> [57.122028] i915_address_space_init+0xa9/0x170 [i915]
> <4> [57.122104] i915_ggtt_init_hw+0x47/0x130 [i915]
> <4> [57.122150] i915_driver_probe+0xbb4/0x15f0 [i915]
> <4> [57.122197] i915_pci_probe+0x43/0x1c0 [i915]
> <4> [57.122202] pci_device_probe+0x9e/0x120
> <4> [57.122206] really_probe+0xea/0x420
> <4> [57.122209] driver_probe_device+0x10b/0x120
> <4> [57.122212] device_driver_attach+0x4a/0x50
> <4> [57.122214] __driver_attach+0x97/0x130
> <4> [57.122217] bus_for_each_dev+0x74/0xc0
> <4> [57.122220] bus_add_driver+0x142/0x220
> <4> [57.122222] driver_register+0x56/0xf0
> <4> [57.122226] do_one_initcall+0x58/0x2ff
> <4> [57.122230] do_init_module+0x56/0x1f8
> <4> [57.122233] load_module+0x243e/0x29f0
> <4> [57.122236] __do_sys_finit_module+0xe9/0x110
> <4> [57.122239] do_syscall_64+0x4f/0x210
> <4> [57.122242] entry_SYSCALL_64_after_hwframe+0x49/0xbe
> <4> [57.122244]
> -> #0 (fs_reclaim){+.+.}:
> <4> [57.122249] __lock_acquire+0x1328/0x15d0
> <4> [57.122251] lock_acquire+0xa7/0x1c0
> <4> [57.122254] fs_reclaim_acquire.part.117+0x24/0x30
> <4> [57.122257] __kmalloc+0x48/0x320
> <4> [57.122261] acpi_ns_internalize_name+0x44/0x9b
> <4> [57.122264] acpi_ns_get_node_unlocked+0x6b/0xd3
> <4> [57.122267] acpi_ns_get_node+0x3b/0x50
> <4> [57.122271] acpi_get_handle+0x8a/0xb4
> <4> [57.122274] acpi_has_method+0x1c/0x40
> <4> [57.122278] acpi_pci_set_power_state+0x40/0xe0
> <4> [57.122281] pci_platform_power_transition+0x3e/0x90
> <4> [57.122284] pci_set_power_state+0x83/0xf0
> <4> [57.122287] pci_restore_standard_config+0x22/0x40
> <4> [57.122289] pci_pm_runtime_resume+0x23/0xc0
> <4> [57.122293] __rpm_callback+0xb1/0x110
> <4> [57.122296] rpm_callback+0x1a/0x70
> <4> [57.122299] rpm_resume+0x50e/0x790
> <4> [57.122302] __pm_runtime_resume+0x42/0x80
> <4> [57.122357] __intel_runtime_pm_get+0x15/0x60 [i915]
> <4> [57.122435] ggtt_unbind_vma+0x24/0x60 [i915]
> <4> [57.122514] __i915_vma_unbind.part.39+0xb5/0x500 [i915]
> <4> [57.122593] i915_vma_unbind+0x2d/0x50 [i915]
> <4> [57.122668] i915_gem_object_unbind+0x11c/0x260 [i915]
> <4> [57.122740] i915_gem_object_set_cache_level+0x32/0x90 [i915]
> <4> [57.122810] i915_gem_set_caching_ioctl+0x1f7/0x2f0 [i915]
> <4> [57.122815] drm_ioctl_kernel+0xa7/0xf0
> <4> [57.122818] drm_ioctl+0x2e1/0x390
> <4> [57.122822] do_vfs_ioctl+0xa0/0x6f0
> <4> [57.122825] ksys_ioctl+0x35/0x60
> <4> [57.122828] __x64_sys_ioctl+0x11/0x20
> <4> [57.122830] do_syscall_64+0x4f/0x210
> <4> [57.122833] entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> Closes: https://gitlab.freedesktop.org/drm/intel/issues/711
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx>
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