From 84bbe327a5cbb060f3321c9d9d4d53936fc1ef9b Mon Sep 17 00:00:00 2001 From: Janusz Krzysztofik Date: Thu, 23 Oct 2025 10:25:19 +0200 Subject: drm/i915: Avoid lock inversion when pinning to GGTT on CHV/BXT+VTD On completion of i915_vma_pin_ww(), a synchronous variant of dma_fence_work_commit() is called. When pinning a VMA to GGTT address space on a Cherry View family processor, or on a Broxton generation SoC with VTD enabled, i.e., when stop_machine() is then called from intel_ggtt_bind_vma(), that can potentially lead to lock inversion among reservation_ww and cpu_hotplug locks. [86.861179] ====================================================== [86.861193] WARNING: possible circular locking dependency detected [86.861209] 6.15.0-rc5-CI_DRM_16515-gca0305cadc2d+ #1 Tainted: G U [86.861226] ------------------------------------------------------ [86.861238] i915_module_loa/1432 is trying to acquire lock: [86.861252] ffffffff83489090 (cpu_hotplug_lock){++++}-{0:0}, at: stop_machine+0x1c/0x50 [86.861290] but task is already holding lock: [86.861303] ffffc90002e0b4c8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_vma_pin.constprop.0+0x39/0x1d0 [i915] [86.862233] which lock already depends on the new lock. [86.862251] the existing dependency chain (in reverse order) is: [86.862265] -> #5 (reservation_ww_class_mutex){+.+.}-{3:3}: [86.862292] dma_resv_lockdep+0x19a/0x390 [86.862315] do_one_initcall+0x60/0x3f0 [86.862334] kernel_init_freeable+0x3cd/0x680 [86.862353] kernel_init+0x1b/0x200 [86.862369] ret_from_fork+0x47/0x70 [86.862383] ret_from_fork_asm+0x1a/0x30 [86.862399] -> #4 (reservation_ww_class_acquire){+.+.}-{0:0}: [86.862425] dma_resv_lockdep+0x178/0x390 [86.862440] do_one_initcall+0x60/0x3f0 [86.862454] kernel_init_freeable+0x3cd/0x680 [86.862470] kernel_init+0x1b/0x200 [86.862482] ret_from_fork+0x47/0x70 [86.862495] ret_from_fork_asm+0x1a/0x30 [86.862509] -> #3 (&mm->mmap_lock){++++}-{3:3}: [86.862531] down_read_killable+0x46/0x1e0 [86.862546] lock_mm_and_find_vma+0xa2/0x280 [86.862561] do_user_addr_fault+0x266/0x8e0 [86.862578] exc_page_fault+0x8a/0x2f0 [86.862593] asm_exc_page_fault+0x27/0x30 [86.862607] filldir64+0xeb/0x180 [86.862620] kernfs_fop_readdir+0x118/0x480 [86.862635] iterate_dir+0xcf/0x2b0 [86.862648] __x64_sys_getdents64+0x84/0x140 [86.862661] x64_sys_call+0x1058/0x2660 [86.862675] do_syscall_64+0x91/0xe90 [86.862689] entry_SYSCALL_64_after_hwframe+0x76/0x7e [86.862703] -> #2 (&root->kernfs_rwsem){++++}-{3:3}: [86.862725] down_write+0x3e/0xf0 [86.862738] kernfs_add_one+0x30/0x3c0 [86.862751] kernfs_create_dir_ns+0x53/0xb0 [86.862765] internal_create_group+0x134/0x4c0 [86.862779] sysfs_create_group+0x13/0x20 [86.862792] topology_add_dev+0x1d/0x30 [86.862806] cpuhp_invoke_callback+0x4b5/0x850 [86.862822] cpuhp_issue_call+0xbf/0x1f0 [86.862836] __cpuhp_setup_state_cpuslocked+0x111/0x320 [86.862852] __cpuhp_setup_state+0xb0/0x220 [86.862866] topology_sysfs_init+0x30/0x50 [86.862879] do_one_initcall+0x60/0x3f0 [86.862893] kernel_init_freeable+0x3cd/0x680 [86.862908] kernel_init+0x1b/0x200 [86.862921] ret_from_fork+0x47/0x70 [86.862934] ret_from_fork_asm+0x1a/0x30 [86.862947] -> #1 (cpuhp_state_mutex){+.+.}-{3:3}: [86.862969] __mutex_lock+0xaa/0xed0 [86.862982] mutex_lock_nested+0x1b/0x30 [86.862995] __cpuhp_setup_state_cpuslocked+0x67/0x320 [86.863012] __cpuhp_setup_state+0xb0/0x220 [86.863026] page_alloc_init_cpuhp+0x2d/0x60 [86.863041] mm_core_init+0x22/0x2d0 [86.863054] start_kernel+0x576/0xbd0 [86.863068] x86_64_start_reservations+0x18/0x30 [86.863084] x86_64_start_kernel+0xbf/0x110 [86.863098] common_startup_64+0x13e/0x141 [86.863114] -> #0 (cpu_hotplug_lock){++++}-{0:0}: [86.863135] __lock_acquire+0x1635/0x2810 [86.863152] lock_acquire+0xc4/0x2f0 [86.863166] cpus_read_lock+0x41/0x100 [86.863180] stop_machine+0x1c/0x50 [86.863194] bxt_vtd_ggtt_insert_entries__BKL+0x3b/0x60 [i915] [86.863987] intel_ggtt_bind_vma+0x43/0x70 [i915] [86.864735] __vma_bind+0x55/0x70 [i915] [86.865510] fence_work+0x26/0xa0 [i915] [86.866248] fence_notify+0xa1/0x140 [i915] [86.866983] __i915_sw_fence_complete+0x8f/0x270 [i915] [86.867719] i915_sw_fence_commit+0x39/0x60 [i915] [86.868453] i915_vma_pin_ww+0x462/0x1360 [i915] [86.869228] i915_vma_pin.constprop.0+0x133/0x1d0 [i915] [86.870001] initial_plane_vma+0x307/0x840 [i915] [86.870774] intel_initial_plane_config+0x33f/0x670 [i915] [86.871546] intel_display_driver_probe_nogem+0x1c6/0x260 [i915] [86.872330] i915_driver_probe+0x7fa/0xe80 [i915] [86.873057] i915_pci_probe+0xe6/0x220 [i915] [86.873782] local_pci_probe+0x47/0xb0 [86.873802] pci_device_probe+0xf3/0x260 [86.873817] really_probe+0xf1/0x3c0 [86.873833] __driver_probe_device+0x8c/0x180 [86.873848] driver_probe_device+0x24/0xd0 [86.873862] __driver_attach+0x10f/0x220 [86.873876] bus_for_each_dev+0x7f/0xe0 [86.873892] driver_attach+0x1e/0x30 [86.873904] bus_add_driver+0x151/0x290 [86.873917] driver_register+0x5e/0x130 [86.873931] __pci_register_driver+0x7d/0x90 [86.873945] i915_pci_register_driver+0x23/0x30 [i915] [86.874678] i915_init+0x37/0x120 [i915] [86.875347] do_one_initcall+0x60/0x3f0 [86.875369] do_init_module+0x97/0x2a0 [86.875385] load_module+0x2c54/0x2d80 [86.875398] init_module_from_file+0x96/0xe0 [86.875413] idempotent_init_module+0x117/0x330 [86.875426] __x64_sys_finit_module+0x77/0x100 [86.875440] x64_sys_call+0x24de/0x2660 [86.875454] do_syscall_64+0x91/0xe90 [86.875470] entry_SYSCALL_64_after_hwframe+0x76/0x7e [86.875486] other info that might help us debug this: [86.875502] Chain exists of: cpu_hotplug_lock --> reservation_ww_class_acquire --> reservation_ww_class_mutex [86.875539] Possible unsafe locking scenario: [86.875552] CPU0 CPU1 [86.875563] ---- ---- [86.875573] lock(reservation_ww_class_mutex); [86.875588] lock(reservation_ww_class_acquire); [86.875606] lock(reservation_ww_class_mutex); [86.875624] rlock(cpu_hotplug_lock); [86.875637] *** DEADLOCK *** [86.875650] 3 locks held by i915_module_loa/1432: [86.875663] #0: ffff888101f5c1b0 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x104/0x220 [86.875699] #1: ffffc90002e0b4a0 (reservation_ww_class_acquire){+.+.}-{0:0}, at: i915_vma_pin.constprop.0+0x39/0x1d0 [i915] [86.876512] #2: ffffc90002e0b4c8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_vma_pin.constprop.0+0x39/0x1d0 [i915] [86.877305] stack backtrace: [86.877326] CPU: 0 UID: 0 PID: 1432 Comm: i915_module_loa Tainted: G U 6.15.0-rc5-CI_DRM_16515-gca0305cadc2d+ #1 PREEMPT(voluntary) [86.877334] Tainted: [U]=USER [86.877336] Hardware name: /NUC5CPYB, BIOS PYBSWCEL.86A.0079.2020.0420.1316 04/20/2020 [86.877339] Call Trace: [86.877344] [86.877353] dump_stack_lvl+0x91/0xf0 [86.877364] dump_stack+0x10/0x20 [86.877369] print_circular_bug+0x285/0x360 [86.877379] check_noncircular+0x135/0x150 [86.877390] __lock_acquire+0x1635/0x2810 [86.877403] lock_acquire+0xc4/0x2f0 [86.877408] ? stop_machine+0x1c/0x50 [86.877422] ? __pfx_bxt_vtd_ggtt_insert_entries__cb+0x10/0x10 [i915] [86.878173] cpus_read_lock+0x41/0x100 [86.878182] ? stop_machine+0x1c/0x50 [86.878191] ? __pfx_bxt_vtd_ggtt_insert_entries__cb+0x10/0x10 [i915] [86.878916] stop_machine+0x1c/0x50 [86.878927] bxt_vtd_ggtt_insert_entries__BKL+0x3b/0x60 [i915] [86.879652] intel_ggtt_bind_vma+0x43/0x70 [i915] [86.880375] __vma_bind+0x55/0x70 [i915] [86.881133] fence_work+0x26/0xa0 [i915] [86.881851] fence_notify+0xa1/0x140 [i915] [86.882566] __i915_sw_fence_complete+0x8f/0x270 [i915] [86.883286] i915_sw_fence_commit+0x39/0x60 [i915] [86.884003] i915_vma_pin_ww+0x462/0x1360 [i915] [86.884756] ? i915_vma_pin.constprop.0+0x6c/0x1d0 [i915] [86.885513] i915_vma_pin.constprop.0+0x133/0x1d0 [i915] [86.886281] initial_plane_vma+0x307/0x840 [i915] [86.887049] intel_initial_plane_config+0x33f/0x670 [i915] [86.887819] intel_display_driver_probe_nogem+0x1c6/0x260 [i915] [86.888587] i915_driver_probe+0x7fa/0xe80 [i915] [86.889293] ? mutex_unlock+0x12/0x20 [86.889301] ? drm_privacy_screen_get+0x171/0x190 [86.889308] ? acpi_dev_found+0x66/0x80 [86.889321] i915_pci_probe+0xe6/0x220 [i915] [86.890038] local_pci_probe+0x47/0xb0 [86.890049] pci_device_probe+0xf3/0x260 [86.890058] really_probe+0xf1/0x3c0 [86.890067] __driver_probe_device+0x8c/0x180 [86.890072] driver_probe_device+0x24/0xd0 [86.890078] __driver_attach+0x10f/0x220 [86.890083] ? __pfx___driver_attach+0x10/0x10 [86.890088] bus_for_each_dev+0x7f/0xe0 [86.890097] driver_attach+0x1e/0x30 [86.890101] bus_add_driver+0x151/0x290 [86.890107] driver_register+0x5e/0x130 [86.890113] __pci_register_driver+0x7d/0x90 [86.890119] i915_pci_register_driver+0x23/0x30 [i915] [86.890833] i915_init+0x37/0x120 [i915] [86.891482] ? __pfx_i915_init+0x10/0x10 [i915] [86.892135] do_one_initcall+0x60/0x3f0 [86.892145] ? __kmalloc_cache_noprof+0x33f/0x470 [86.892157] do_init_module+0x97/0x2a0 [86.892164] load_module+0x2c54/0x2d80 [86.892168] ? __kernel_read+0x15c/0x300 [86.892185] ? kernel_read_file+0x2b1/0x320 [86.892195] init_module_from_file+0x96/0xe0 [86.892199] ? init_module_from_file+0x96/0xe0 [86.892211] idempotent_init_module+0x117/0x330 [86.892224] __x64_sys_finit_module+0x77/0x100 [86.892230] x64_sys_call+0x24de/0x2660 [86.892236] do_syscall_64+0x91/0xe90 [86.892243] ? irqentry_exit+0x77/0xb0 [86.892249] ? sysvec_apic_timer_interrupt+0x57/0xc0 [86.892256] entry_SYSCALL_64_after_hwframe+0x76/0x7e [86.892261] RIP: 0033:0x7303e1b2725d [86.892271] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 8b bb 0d 00 f7 d8 64 89 01 48 [86.892276] RSP: 002b:00007ffddd1fdb38 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 [86.892281] RAX: ffffffffffffffda RBX: 00005d771d88fd90 RCX: 00007303e1b2725d [86.892285] RDX: 0000000000000000 RSI: 00005d771d893aa0 RDI: 000000000000000c [86.892287] RBP: 00007ffddd1fdbf0 R08: 0000000000000040 R09: 00007ffddd1fdb80 [86.892289] R10: 00007303e1c03b20 R11: 0000000000000246 R12: 00005d771d893aa0 [86.892292] R13: 0000000000000000 R14: 00005d771d88f0d0 R15: 00005d771d895710 [86.892304] Call asynchronous variant of dma_fence_work_commit() in that case. v3: Provide more verbose in-line comment (Andi), - mention target environments in commit message. Fixes: 7d1c2618eac59 ("drm/i915: Take reservation lock around i915_vma_pin.") Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14985 Cc: Andi Shyti Signed-off-by: Janusz Krzysztofik Reviewed-by: Sebastian Brzezinka Reviewed-by: Krzysztof Karas Acked-by: Andi Shyti Signed-off-by: Andi Shyti Link: https://lore.kernel.org/r/20251023082925.351307-6-janusz.krzysztofik@linux.intel.com (cherry picked from commit 648ef1324add1c2e2b6041cdf0b28d31fbca5f13) Signed-off-by: Rodrigo Vivi --- drivers/gpu/drm/i915/i915_vma.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index 25e97031d76e..30d5889fc809 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -1595,8 +1595,20 @@ err_unlock: err_vma_res: i915_vma_resource_free(vma_res); err_fence: - if (work) - dma_fence_work_commit_imm(&work->base); + if (work) { + /* + * When pinning VMA to GGTT on CHV or BXT with VTD enabled, + * commit VMA binding asynchronously to avoid risk of lock + * inversion among reservation_ww locks held here and + * cpu_hotplug_lock acquired from stop_machine(), which we + * wrap around GGTT updates when running in those environments. + */ + if (i915_vma_is_ggtt(vma) && + intel_vm_no_concurrent_access_wa(vma->vm->i915)) + dma_fence_work_commit(&work->base); + else + dma_fence_work_commit_imm(&work->base); + } err_rpm: intel_runtime_pm_put(&vma->vm->i915->runtime_pm, wakeref); -- cgit From 7d44ad6b43d0be43d080180413a1b6c24cfbd266 Mon Sep 17 00:00:00 2001 From: Umesh Nerlige Ramappa Date: Wed, 15 Oct 2025 17:03:51 -0700 Subject: drm/i915: Fix conversion between clock ticks and nanoseconds When tick values are large, the multiplication by NSEC_PER_SEC is larger than 64 bits and results in bad conversions. The issue is seen in PMU busyness counters that look like they have wrapped around due to bad conversion. i915 PMU implementation returns monotonically increasing counters. If a count is lesser than previous one, it will only return the larger value until the smaller value catches up. The user will see this as zero delta between two measurements even though the engines are busy. Fix it by using mul_u64_u32_div() Fixes: 77cdd054dd2c ("drm/i915/pmu: Connect engine busyness stats from GuC to pmu") Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14955 Signed-off-by: Umesh Nerlige Ramappa Reviewed-by: Ashutosh Dixit Link: https://lore.kernel.org/r/20251016000350.1152382-2-umesh.nerlige.ramappa@intel.com (cherry picked from commit 2ada9cb1df3f5405a01d013b708b1b0914efccfe) Signed-off-by: Rodrigo Vivi [Rodrigo: Added the Fixes tag while cherry-picking to fixes] --- drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c b/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c index 88b147fa5cb1..c90b35881a26 100644 --- a/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c +++ b/drivers/gpu/drm/i915/gt/intel_gt_clock_utils.c @@ -205,7 +205,7 @@ static u64 div_u64_roundup(u64 nom, u32 den) u64 intel_gt_clock_interval_to_ns(const struct intel_gt *gt, u64 count) { - return div_u64_roundup(count * NSEC_PER_SEC, gt->clock_frequency); + return mul_u64_u32_div(count, NSEC_PER_SEC, gt->clock_frequency); } u64 intel_gt_pm_interval_to_ns(const struct intel_gt *gt, u64 count) @@ -215,7 +215,7 @@ u64 intel_gt_pm_interval_to_ns(const struct intel_gt *gt, u64 count) u64 intel_gt_ns_to_clock_interval(const struct intel_gt *gt, u64 ns) { - return div_u64_roundup(gt->clock_frequency * ns, NSEC_PER_SEC); + return mul_u64_u32_div(ns, gt->clock_frequency, NSEC_PER_SEC); } u64 intel_gt_ns_to_pm_interval(const struct intel_gt *gt, u64 ns) -- cgit