[PATCH 02/11] drm/i915/selftests: Appease lockdep

Chris Wilson chris at chris-wilson.co.uk
Sat Oct 5 10:46:35 UTC 2019


Disable irqs around updating the context image to keep lockdep happy:

<4>[  673.483340] WARNING: possible irq lock inversion dependency detected
<4>[  673.483342] 5.4.0-rc1-CI-Trybot_5118+ #1 Tainted: G     U
<4>[  673.483342] --------------------------------------------------------
<4>[  673.483343] swapper/2/0 just changed the state of lock:
<4>[  673.483344] ffff88845db885a0 (&i915_request_get(rq)->submit/1){-...}, at: __i915_sw_fence_complete+0x1b2/0x250 [i915]
<4>[  673.483387] but this lock took another, HARDIRQ-unsafe lock in the past:
<4>[  673.483388]  (&ce->pin_mutex/2){+...}
<4>[  673.483389]

                  and interrupts could create inverse lock ordering between them.

<4>[  673.483390]
                  other info that might help us debug this:
<4>[  673.483390] Chain exists of:
                    &i915_request_get(rq)->submit/1 --> &engine->active.lock --> &ce->pin_mutex/2

<4>[  673.483392]  Possible interrupt unsafe locking scenario:

<4>[  673.483392]        CPU0                    CPU1
<4>[  673.483393]        ----                    ----
<4>[  673.483393]   lock(&ce->pin_mutex/2);
<4>[  673.483394]                                local_irq_disable();
<4>[  673.483395]                                lock(&i915_request_get(rq)->submit/1);
<4>[  673.483396]                                lock(&engine->active.lock);
<4>[  673.483396]   <Interrupt>
<4>[  673.483397]     lock(&i915_request_get(rq)->submit/1);
<4>[  673.483398]
                   *** DEADLOCK ***

<4>[  673.483398] 2 locks held by swapper/2/0:
<4>[  673.483399]  #0: ffff8883f61ac9b0 (&(&gt->irq_lock)->rlock){-.-.}, at: gen11_gt_irq_handler+0x42/0x280 [i915]
<4>[  673.483433]  #1: ffff88845db8c418 (&(&rq->lock)->rlock){-.-.}, at: intel_engine_breadcrumbs_irq+0x34a/0x5a0 [i915]
<4>[  673.483463]
                  the shortest dependencies between 2nd lock and 1st lock:
<4>[  673.483466]   -> (&ce->pin_mutex/2){+...} ops: 614520 {
<4>[  673.483468]      HARDIRQ-ON-W at:
<4>[  673.483471]                         lock_acquire+0xa7/0x1c0
<4>[  673.483501]                         live_unlite_restore+0x1d8/0x6c0 [i915]
<4>[  673.483543]                         __i915_subtests+0xb8/0x210 [i915]
<4>[  673.483581]                         __run_selftests+0x112/0x170 [i915]
<4>[  673.483615]                         i915_live_selftests+0x2c/0x60 [i915]
<4>[  673.483644]                         i915_pci_probe+0x93/0x1b0 [i915]
<4>[  673.483646]                         pci_device_probe+0x9e/0x120
<4>[  673.483648]                         really_probe+0xea/0x420
<4>[  673.483649]                         driver_probe_device+0x10b/0x120
<4>[  673.483651]                         device_driver_attach+0x4a/0x50
<4>[  673.483652]                         __driver_attach+0x97/0x130
<4>[  673.483653]                         bus_for_each_dev+0x74/0xc0
<4>[  673.483654]                         bus_add_driver+0x142/0x220
<4>[  673.483655]                         driver_register+0x56/0xf0
<4>[  673.483657]                         do_one_initcall+0x58/0x2ff
<4>[  673.483659]                         do_init_module+0x56/0x1f8
<4>[  673.483660]                         load_module+0x243e/0x29f0
<4>[  673.483661]                         __do_sys_finit_module+0xe9/0x110
<4>[  673.483662]                         do_syscall_64+0x4f/0x210
<4>[  673.483665]                         entry_SYSCALL_64_after_hwframe+0x49/0xbe
<4>[  673.483665]      INITIAL USE at:
<4>[  673.483667]                        lock_acquire+0xa7/0x1c0
<4>[  673.483698]                        live_unlite_restore+0x1d8/0x6c0 [i915]
<4>[  673.483733]                        __i915_subtests+0xb8/0x210 [i915]
<4>[  673.483764]                        __run_selftests+0x112/0x170 [i915]
<4>[  673.483793]                        i915_live_selftests+0x2c/0x60 [i915]
<4>[  673.483821]                        i915_pci_probe+0x93/0x1b0 [i915]
<4>[  673.483822]                        pci_device_probe+0x9e/0x120
<4>[  673.483824]                        really_probe+0xea/0x420
<4>[  673.483825]                        driver_probe_device+0x10b/0x120
<4>[  673.483826]                        device_driver_attach+0x4a/0x50
<4>[  673.483827]                        __driver_attach+0x97/0x130
<4>[  673.483828]                        bus_for_each_dev+0x74/0xc0
<4>[  673.483829]                        bus_add_driver+0x142/0x220
<4>[  673.483830]                        driver_register+0x56/0xf0
<4>[  673.483831]                        do_one_initcall+0x58/0x2ff
<4>[  673.483833]                        do_init_module+0x56/0x1f8
<4>[  673.483834]                        load_module+0x243e/0x29f0
<4>[  673.483835]                        __do_sys_finit_module+0xe9/0x110
<4>[  673.483836]                        do_syscall_64+0x4f/0x210
<4>[  673.483837]                        entry_SYSCALL_64_after_hwframe+0x49/0xbe
<4>[  673.483838]    }
<4>[  673.483868]    ... key      at: [<ffffffffa0a8f132>] __key.70113+0x2/0xffffffffffef2ed0 [i915]
<4>[  673.483869]    ... acquired at:
<4>[  673.483935]    __execlists_reset+0xfb/0xc20 [i915]
<4>[  673.483965]    execlists_reset+0x3d/0x50 [i915]
<4>[  673.483995]    intel_engine_reset+0xdf/0x230 [i915]
<4>[  673.484022]    live_preempt_hang+0x1d7/0x2e0 [i915]
<4>[  673.484064]    __i915_subtests+0xb8/0x210 [i915]
<4>[  673.484130]    __run_selftests+0x112/0x170 [i915]
<4>[  673.484163]    i915_live_selftests+0x2c/0x60 [i915]
<4>[  673.484193]    i915_pci_probe+0x93/0x1b0 [i915]
<4>[  673.484194]    pci_device_probe+0x9e/0x120
<4>[  673.484195]    really_probe+0xea/0x420
<4>[  673.484196]    driver_probe_device+0x10b/0x120
<4>[  673.484197]    device_driver_attach+0x4a/0x50
<4>[  673.484198]    __driver_attach+0x97/0x130
<4>[  673.484199]    bus_for_each_dev+0x74/0xc0
<4>[  673.484200]    bus_add_driver+0x142/0x220
<4>[  673.484202]    driver_register+0x56/0xf0
<4>[  673.484203]    do_one_initcall+0x58/0x2ff
<4>[  673.484204]    do_init_module+0x56/0x1f8
<4>[  673.484205]    load_module+0x243e/0x29f0
<4>[  673.484206]    __do_sys_finit_module+0xe9/0x110
<4>[  673.484207]    do_syscall_64+0x4f/0x210
<4>[  673.484208]    entry_SYSCALL_64_after_hwframe+0x49/0xbe

<4>[  673.484209]  -> (&engine->active.lock){..-.} ops: 972791 {
<4>[  673.484211]     IN-SOFTIRQ-W at:
<4>[  673.484213]                       lock_acquire+0xa7/0x1c0
<4>[  673.484214]                       _raw_spin_lock_irqsave+0x33/0x50
<4>[  673.484244]                       execlists_submission_tasklet+0xaf/0x100 [i915]
<4>[  673.484246]                       tasklet_action_common.isra.18+0x6c/0x1c0
<4>[  673.484247]                       __do_softirq+0xdf/0x47f
<4>[  673.484248]                       irq_exit+0xba/0xc0
<4>[  673.484249]                       do_IRQ+0x83/0x160
<4>[  673.484250]                       ret_from_intr+0x0/0x1d
<4>[  673.484252]                       cpuidle_enter_state+0xb2/0x450
<4>[  673.484253]                       cpuidle_enter+0x24/0x40
<4>[  673.484254]                       do_idle+0x1e7/0x250
<4>[  673.484256]                       cpu_startup_entry+0x14/0x20
<4>[  673.484257]                       start_secondary+0x15f/0x1b0
<4>[  673.484258]                       secondary_startup_64+0xa4/0xb0
<4>[  673.484259]     INITIAL USE at:
<4>[  673.484261]                      lock_acquire+0xa7/0x1c0
<4>[  673.484290]                      intel_engine_init_active+0x7e/0xb0 [i915]
<4>[  673.484305]                      intel_engines_setup+0x1cd/0x3b0 [i915]
<4>[  673.484305]                      i915_gem_init+0x12d/0x900 [i915]
<4>[  673.484305]                      i915_driver_probe+0xb70/0x15d0 [i915]
<4>[  673.484305]                      i915_pci_probe+0x43/0x1b0 [i915]
<4>[  673.484305]                      pci_device_probe+0x9e/0x120
<4>[  673.484305]                      really_probe+0xea/0x420
<4>[  673.484305]                      driver_probe_device+0x10b/0x120
<4>[  673.484305]                      device_driver_attach+0x4a/0x50
<4>[  673.484305]                      __driver_attach+0x97/0x130
<4>[  673.484305]                      bus_for_each_dev+0x74/0xc0
<4>[  673.484305]                      bus_add_driver+0x142/0x220
<4>[  673.484305]                      driver_register+0x56/0xf0
<4>[  673.484305]                      do_one_initcall+0x58/0x2ff
<4>[  673.484305]                      do_init_module+0x56/0x1f8
<4>[  673.484305]                      load_module+0x243e/0x29f0
<4>[  673.484305]                      __do_sys_finit_module+0xe9/0x110
<4>[  673.484305]                      do_syscall_64+0x4f/0x210
<4>[  673.484305]                      entry_SYSCALL_64_after_hwframe+0x49/0xbe
<4>[  673.484305]   }
<4>[  673.484305]   ... key      at: [<ffffffffa0a8f160>] __key.70307+0x0/0xffffffffffef2ea0 [i915]
<4>[  673.484305]   ... acquired at:
<4>[  673.484305]    _raw_spin_lock_irqsave+0x33/0x50
<4>[  673.484305]    execlists_submit_request+0x2b/0x1e0 [i915]
<4>[  673.484305]    submit_notify+0xa8/0x13c [i915]
<4>[  673.484305]    __i915_sw_fence_complete+0x81/0x250 [i915]
<4>[  673.484305]    i915_sw_fence_wake+0x51/0x70 [i915]
<4>[  673.484305]    __i915_sw_fence_complete+0x1ee/0x250 [i915]
<4>[  673.484305]    dma_i915_sw_fence_wake+0x1b/0x30 [i915]
<4>[  673.484305]    dma_fence_signal_locked+0x9e/0x1b0
<4>[  673.484305]    dma_fence_signal+0x1f/0x40
<4>[  673.484305]    fence_work+0x28/0x80 [i915]
<4>[  673.484305]    process_one_work+0x26a/0x620
<4>[  673.484305]    worker_thread+0x37/0x380
<4>[  673.484305]    kthread+0x119/0x130
<4>[  673.484305]    ret_from_fork+0x24/0x50

<4>[  673.484305] -> (&i915_request_get(rq)->submit/1){-...} ops: 857694 {
<4>[  673.484305]    IN-HARDIRQ-W at:
<4>[  673.484305]                     lock_acquire+0xa7/0x1c0
<4>[  673.484305]                     _raw_spin_lock_irqsave_nested+0x39/0x50
<4>[  673.484305]                     __i915_sw_fence_complete+0x1b2/0x250 [i915]
<4>[  673.484305]                     intel_engine_breadcrumbs_irq+0x3d0/0x5a0 [i915]
<4>[  673.484305]                     cs_irq_handler+0x39/0x50 [i915]
<4>[  673.484305]                     gen11_gt_irq_handler+0x17b/0x280 [i915]
<4>[  673.484305]                     gen11_irq_handler+0x54/0xf0 [i915]
<4>[  673.484305]                     __handle_irq_event_percpu+0x41/0x2c0
<4>[  673.484305]                     handle_irq_event_percpu+0x2b/0x70
<4>[  673.484305]                     handle_irq_event+0x2f/0x50
<4>[  673.484305]                     handle_edge_irq+0x99/0x1b0
<4>[  673.484305]                     do_IRQ+0x7e/0x160
<4>[  673.484305]                     ret_from_intr+0x0/0x1d
<4>[  673.484305]                     cpuidle_enter_state+0xb2/0x450
<4>[  673.484305]                     cpuidle_enter+0x24/0x40
<4>[  673.484305]                     do_idle+0x1e7/0x250
<4>[  673.484305]                     cpu_startup_entry+0x14/0x20
<4>[  673.484305]                     start_secondary+0x15f/0x1b0
<4>[  673.484305]                     secondary_startup_64+0xa4/0xb0
<4>[  673.484305]    INITIAL USE at:
<4>[  673.484305]                    lock_acquire+0xa7/0x1c0
<4>[  673.484305]                    _raw_spin_lock_irqsave_nested+0x39/0x50
<4>[  673.484305]                    __i915_sw_fence_complete+0x1b2/0x250 [i915]
<4>[  673.484305]                    __engine_park+0x233/0x420 [i915]
<4>[  673.484305]                    ____intel_wakeref_put_last+0x1c/0x70 [i915]
<4>[  673.484305]                    intel_gt_resume+0x202/0x2c0 [i915]
<4>[  673.484305]                    i915_gem_init+0x36e/0x900 [i915]
<4>[  673.484305]                    i915_driver_probe+0xb70/0x15d0 [i915]
<4>[  673.484305]                    i915_pci_probe+0x43/0x1b0 [i915]
<4>[  673.484305]                    pci_device_probe+0x9e/0x120
<4>[  673.484305]                    really_probe+0xea/0x420
<4>[  673.484305]                    driver_probe_device+0x10b/0x120
<4>[  673.484305]                    device_driver_attach+0x4a/0x50
<4>[  673.484305]                    __driver_attach+0x97/0x130
<4>[  673.484305]                    bus_for_each_dev+0x74/0xc0
<4>[  673.484305]                    bus_add_driver+0x142/0x220
<4>[  673.484305]                    driver_register+0x56/0xf0
<4>[  673.484305]                    do_one_initcall+0x58/0x2ff
<4>[  673.484305]                    do_init_module+0x56/0x1f8
<4>[  673.484305]                    load_module+0x243e/0x29f0
<4>[  673.484305]                    __do_sys_finit_module+0xe9/0x110
<4>[  673.484305]                    do_syscall_64+0x4f/0x210
<4>[  673.484305]                    entry_SYSCALL_64_after_hwframe+0x49/0xbe
<4>[  673.484305]  }
<4>[  673.484305]  ... key      at: [<ffffffffa0a8f6a1>] __key.80173+0x1/0xffffffffffef2960 [i915]
<4>[  673.484305]  ... acquired at:
<4>[  673.484305]    mark_lock+0x382/0x500
<4>[  673.484305]    __lock_acquire+0x7e1/0x15d0
<4>[  673.484305]    lock_acquire+0xa7/0x1c0
<4>[  673.484305]    _raw_spin_lock_irqsave_nested+0x39/0x50
<4>[  673.484305]    __i915_sw_fence_complete+0x1b2/0x250 [i915]
<4>[  673.484305]    intel_engine_breadcrumbs_irq+0x3d0/0x5a0 [i915]
<4>[  673.484305]    cs_irq_handler+0x39/0x50 [i915]
<4>[  673.484305]    gen11_gt_irq_handler+0x17b/0x280 [i915]
<4>[  673.484305]    gen11_irq_handler+0x54/0xf0 [i915]
<4>[  673.484305]    __handle_irq_event_percpu+0x41/0x2c0
<4>[  673.484305]    handle_irq_event_percpu+0x2b/0x70
<4>[  673.484305]    handle_irq_event+0x2f/0x50
<4>[  673.484305]    handle_edge_irq+0x99/0x1b0
<4>[  673.484305]    do_IRQ+0x7e/0x160
<4>[  673.484305]    ret_from_intr+0x0/0x1d
<4>[  673.484305]    cpuidle_enter_state+0xb2/0x450
<4>[  673.484305]    cpuidle_enter+0x24/0x40
<4>[  673.484305]    do_idle+0x1e7/0x250
<4>[  673.484305]    cpu_startup_entry+0x14/0x20
<4>[  673.484305]    start_secondary+0x15f/0x1b0
<4>[  673.484305]    secondary_startup_64+0xa4/0xb0

<4>[  673.484305]
                  stack backtrace:
<4>[  673.484305] CPU: 2 PID: 0 Comm: swapper/2 Tainted: G     U            5.4.0-rc1-CI-Trybot_5118+ #1
<4>[  673.484305] Hardware name: Intel Corporation Ice Lake Client Platform/IceLake U DDR4 SODIMM PD RVP TLC, BIOS ICLSFWR1.R00.3183.A00.1905020411 05/02/2019
<4>[  673.484305] Call Trace:
<4>[  673.484305]  <IRQ>
<4>[  673.484305]  dump_stack+0x67/0x9b
<4>[  673.484305]  check_usage_forwards+0x13c/0x150
<4>[  673.484305]  ? mark_lock+0x382/0x500
<4>[  673.484305]  mark_lock+0x382/0x500
<4>[  673.484305]  ? check_usage_backwards+0x140/0x140
<4>[  673.484305]  __lock_acquire+0x7e1/0x15d0
<4>[  673.484305]  ? debug_object_deactivate+0x17e/0x190
<4>[  673.484305]  lock_acquire+0xa7/0x1c0
<4>[  673.484305]  ? __i915_sw_fence_complete+0x1b2/0x250 [i915]
<4>[  673.484305]  _raw_spin_lock_irqsave_nested+0x39/0x50
<4>[  673.484305]  ? __i915_sw_fence_complete+0x1b2/0x250 [i915]
<4>[  673.484305]  __i915_sw_fence_complete+0x1b2/0x250 [i915]
<4>[  673.484305]  intel_engine_breadcrumbs_irq+0x3d0/0x5a0 [i915]
<4>[  673.484305]  cs_irq_handler+0x39/0x50 [i915]
<4>[  673.484305]  gen11_gt_irq_handler+0x17b/0x280 [i915]
<4>[  673.484305]  gen11_irq_handler+0x54/0xf0 [i915]
<4>[  673.484305]  __handle_irq_event_percpu+0x41/0x2c0
<4>[  673.484305]  handle_irq_event_percpu+0x2b/0x70
<4>[  673.484305]  handle_irq_event+0x2f/0x50
<4>[  673.484305]  handle_edge_irq+0x99/0x1b0
<4>[  673.484305]  do_IRQ+0x7e/0x160
<4>[  673.484305]  common_interrupt+0xf/0xf
<4>[  673.484305]  </IRQ>

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gt/selftest_lrc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
index 393ae5321e1d..198cf2f754f4 100644
--- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
+++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
@@ -143,11 +143,11 @@ static int live_unlite_restore(struct drm_i915_private *i915, int prio)
 		GEM_BUG_ON(!ce[1]->ring->size);
 		intel_ring_reset(ce[1]->ring, ce[1]->ring->size / 2);
 
-		local_bh_disable(); /* appease lockdep */
+		local_irq_disable(); /* appease lockdep */
 		__context_pin_acquire(ce[1]);
 		__execlists_update_reg_state(ce[1], engine);
 		__context_pin_release(ce[1]);
-		local_bh_enable();
+		local_irq_enable();
 
 		rq[0] = igt_spinner_create_request(&spin, ce[0], MI_ARB_CHECK);
 		if (IS_ERR(rq[0])) {
-- 
2.23.0



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