Re: [PATCH 4/7] drm/bridge: lock the encoder chain in scoped for_each loops

kernel test robot
2025-09-30T06:16:46Z

Hello,

kernel test robot noticed "BUG:workqueue_lockup-pool" on:

commit: a3ae9f413a9785cbf472a3168131747f79722d31 ("[PATCH 4/7] drm/bridge: lock the encoder chain in scoped for_each loops")
url: https://github.com/intel-lab-lkp/linux/commits/Luca-Ceresoli/drm-encoder-add-mutex-to-protect-the-bridge-chain/20250927-000253
patch link: https://lore.kernel.org/all/20250926-drm-bridge-alloc-encoder-chain-mutex-v1-4-23b62c47356a@bootlin.com/
patch subject: [PATCH 4/7] drm/bridge: lock the encoder chain in scoped for_each loops

in testcase: boot

config: x86_64-randconfig-071-20250929
compiler: clang-20
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G

(please refer to attached dmesg/kmsg for entire log/backtrace)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202509301358.38036b85-lkp@intel.com

[ 63.465088][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 45s!
[ 63.465385][ C0] Showing busy workqueues and worker pools:
[ 63.465405][ C0] workqueue mm_percpu_wq: flags=0x8
[ 63.465454][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 63.465500][ C0] pending: vmstat_update
[ 63.465696][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 94.185049][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 76s!
[ 94.185123][ C0] Showing busy workqueues and worker pools:
[ 94.185136][ C0] workqueue mm_percpu_wq: flags=0x8
[ 94.185146][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 94.185169][ C0] pending: vmstat_update
[ 94.185278][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 124.905021][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 107s!
[ 124.905073][ C0] Showing busy workqueues and worker pools:
[ 124.905080][ C0] workqueue mm_percpu_wq: flags=0x8
[ 124.905087][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 124.905100][ C0] pending: vmstat_update
[ 124.905172][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 155.624991][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 137s!
[ 155.625049][ C0] Showing busy workqueues and worker pools:
[ 155.625057][ C0] workqueue mm_percpu_wq: flags=0x8
[ 155.625065][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 155.625081][ C0] pending: vmstat_update
[ 155.625161][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 186.345006][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 168s!
[ 186.345099][ C0] Showing busy workqueues and worker pools:
[ 186.345111][ C0] workqueue mm_percpu_wq: flags=0x8
[ 186.345123][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 186.345151][ C0] pending: vmstat_update
[ 186.345277][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 217.065070][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 199s!
[ 217.065206][ C0] Showing busy workqueues and worker pools:
[ 217.065227][ C0] workqueue mm_percpu_wq: flags=0x8
[ 217.065247][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 217.065290][ C0] pending: vmstat_update
[ 217.065477][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 247.785028][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 230s!
[ 247.785093][ C0] Showing busy workqueues and worker pools:
[ 247.785104][ C0] workqueue mm_percpu_wq: flags=0x8
[ 247.785112][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 247.785130][ C0] pending: vmstat_update
[ 247.785223][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 278.504990][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 260s!
[ 278.505051][ C0] Showing busy workqueues and worker pools:
[ 278.505062][ C0] workqueue mm_percpu_wq: flags=0x8
[ 278.505069][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 278.505086][ C0] pending: vmstat_update
[ 278.505169][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 309.224985][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 291s!
[ 309.225073][ C0] Showing busy workqueues and worker pools:
[ 309.225085][ C0] workqueue mm_percpu_wq: flags=0x8
[ 309.225097][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 309.225122][ C0] pending: vmstat_update
[ 309.225238][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 339.944986][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 322s!
[ 339.945076][ C0] Showing busy workqueues and worker pools:
[ 339.945089][ C0] workqueue mm_percpu_wq: flags=0x8
[ 339.945102][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 339.945130][ C0] pending: vmstat_update
[ 339.945258][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 370.665059][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 352s!
[ 370.665192][ C0] Showing busy workqueues and worker pools:
[ 370.665212][ C0] workqueue mm_percpu_wq: flags=0x8
[ 370.665233][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 370.665276][ C0] pending: vmstat_update
[ 370.665467][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 401.385016][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 383s!
[ 401.385074][ C0] Showing busy workqueues and worker pools:
[ 401.385085][ C0] workqueue mm_percpu_wq: flags=0x8
[ 401.385092][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 401.385108][ C0] pending: vmstat_update
[ 401.385195][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 432.104963][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 414s!
[ 432.105013][ C0] Showing busy workqueues and worker pools:
[ 432.105021][ C0] workqueue mm_percpu_wq: flags=0x8
[ 432.105027][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 432.105041][ C0] pending: vmstat_update
[ 432.105111][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 462.824979][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 445s!
[ 462.825065][ C0] Showing busy workqueues and worker pools:
[ 462.825076][ C0] workqueue mm_percpu_wq: flags=0x8
[ 462.825087][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 462.825112][ C0] pending: vmstat_update
[ 462.825229][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 493.544976][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 475s!
[ 493.545072][ C0] Showing busy workqueues and worker pools:
[ 493.545084][ C0] workqueue mm_percpu_wq: flags=0x8
[ 493.545096][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 493.545124][ C0] pending: vmstat_update
[ 493.545252][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 524.265024][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 506s!
[ 524.265136][ C0] Showing busy workqueues and worker pools:
[ 524.265153][ C0] workqueue mm_percpu_wq: flags=0x8
[ 524.265170][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 524.265206][ C0] pending: vmstat_update
[ 524.265371][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 554.985000][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 537s!
[ 554.985069][ C0] Showing busy workqueues and worker pools:
[ 554.985080][ C0] workqueue mm_percpu_wq: flags=0x8
[ 554.985089][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 554.985107][ C0] pending: vmstat_update
[ 554.985213][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 585.704946][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 567s!
[ 585.704998][ C0] Showing busy workqueues and worker pools:
[ 585.705006][ C0] workqueue mm_percpu_wq: flags=0x8
[ 585.705013][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 585.705026][ C0] pending: vmstat_update
[ 585.705098][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 616.424942][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 598s!
[ 616.424990][ C0] Showing busy workqueues and worker pools:
[ 616.424997][ C0] workqueue mm_percpu_wq: flags=0x8
[ 616.425003][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 616.425015][ C0] pending: vmstat_update
[ 616.425082][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 647.144950][ C0] BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 629s!
[ 647.145035][ C0] Showing busy workqueues and worker pools:
[ 647.145047][ C0] workqueue mm_percpu_wq: flags=0x8
[ 647.145059][ C0] pwq 6: cpus=1 node=0 flags=0x0 nice=0 active=1 refcnt=2
[ 647.145084][ C0] pending: vmstat_update
[ 647.145202][ C0] Showing backtraces of running workers in stalled CPU-bound worker pools:
[ 674.477504][ C1] watchdog: BUG: soft lockup - CPU#1 stuck for 626s! [swapper/0:1]
[ 674.477539][ C1] CPU#1 Utilization every 96s during lockup:
[ 674.477543][ C1] #1: 100% system, 1% softirq, 1% hardirq, 0% idle
[ 674.477549][ C1] #2: 100% system, 1% softirq, 1% hardirq, 0% idle
[ 674.477553][ C1] #3: 100% system, 0% softirq, 1% hardirq, 0% idle
[ 674.477557][ C1] #4: 100% system, 1% softirq, 1% hardirq, 0% idle
[ 674.477561][ C1] #5: 100% system, 1% softirq, 1% hardirq, 0% idle
[ 674.477566][ C1] Modules linked in:
[ 674.477571][ C1] irq event stamp: 852298
[ 674.477574][ C1] hardirqs last enabled at (852297): asm_sysvec_apic_timer_interrupt (arch/x86/include/asm/idtentry.h:702)
[ 674.477592][ C1] hardirqs last disabled at (852298): sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050)
[ 674.477603][ C1] softirqs last enabled at (852280): handle_softirqs (arch/x86/include/asm/preempt.h:27 kernel/softirq.c:426 kernel/softirq.c:607)
[ 674.477612][ C1] softirqs last disabled at (852275): __irq_exit_rcu (arch/x86/include/asm/jump_label.h:36 kernel/softirq.c:682)
[ 674.477622][ C1] CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.17.0-rc6-01063-ga3ae9f413a97 #1 VOLUNTARY
[ 674.477629][ C1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 674.477634][ C1] RIP: 0010:__sanitizer_cov_trace_pc (arch/x86/include/asm/preempt.h:27 kernel/kcov.c:183 kernel/kcov.c:217)
[ 674.477644][ C1] Code: 48 c7 c7 00 a1 59 8a 48 89 de e8 be 1e 42 01 eb 85 cc cc cc cc cc cc cc cc cc cc cc cc 48 8b 04 24 65 48 8b 0c 25 08 30 0a 8d <65> 8b 15 dc c0 97 0b 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75
All code
========
0: 48 c7 c7 00 a1 59 8a mov $0xffffffff8a59a100,%rdi
7: 48 89 de mov %rbx,%rsi
a: e8 be 1e 42 01 call 0x1421ecd
f: eb 85 jmp 0xffffffffffffff96
11: cc int3
12: cc int3
13: cc int3
14: cc int3
15: cc int3
16: cc int3
17: cc int3
18: cc int3
19: cc int3
1a: cc int3
1b: cc int3
1c: cc int3
1d: 48 8b 04 24 mov (%rsp),%rax
21: 65 48 8b 0c 25 08 30 mov %gs:0xffffffff8d0a3008,%rcx
28: 0a 8d
2a:* 65 8b 15 dc c0 97 0b mov %gs:0xb97c0dc(%rip),%edx # 0xb97c10d <-- trapping instruction
31: 81 e2 00 01 ff 00 and $0xff0100,%edx
37: 74 11 je 0x4a
39: 81 fa 00 01 00 00 cmp $0x100,%edx
3f: 75 .byte 0x75

Code starting with the faulting instruction
===========================================
0: 65 8b 15 dc c0 97 0b mov %gs:0xb97c0dc(%rip),%edx # 0xb97c0e3
7: 81 e2 00 01 ff 00 and $0xff0100,%edx
d: 74 11 je 0x20
f: 81 fa 00 01 00 00 cmp $0x100,%edx
15: 75 .byte 0x75
[ 674.477650][ C1] RSP: 0018:ffffc9000001f138 EFLAGS: 00200287
[ 674.477656][ C1] RAX: ffffffff831e1d39 RBX: ffff888160a713c0 RCX: ffff888100871b00
[ 674.477660][ C1] RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8bc06cf0
[ 674.477664][ C1] RBP: 0000000000000032 R08: ffffffff8bc06cf7 R09: 1ffffffff1780d9e
[ 674.477669][ C1] R10: dffffc0000000000 R11: fffffbfff1780d9f R12: dffffc0000000000
[ 674.477674][ C1] R13: 1ffff1102c14e27e R14: 0000000000000000 R15: ffff88817b2bd5a0
[ 674.477678][ C1] FS: 0000000000000000(0000) GS:ffff88842127d000(0000) knlGS:0000000000000000
[ 674.477683][ C1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 674.477687][ C1] CR2: 00000000f7f5ecd4 CR3: 000000000a0c3000 CR4: 00000000000406f0
[ 674.477695][ C1] Call Trace:
[ 674.477710][ C1] <TASK>
[ 674.477713][ C1] drm_atomic_add_encoder_bridges (drivers/gpu/drm/drm_atomic.c:1319 (discriminator 1025))
[ 674.477734][ C1] drm_atomic_helper_check_modeset (drivers/gpu/drm/drm_atomic_helper.c:818)
[ 674.477767][ C1] drm_atomic_helper_check (drivers/gpu/drm/drm_atomic_helper.c:1112)
[ 674.477775][ C1] ? vgem_fence_release (drivers/gpu/drm/vkms/vkms_drv.c:95)
[ 674.477786][ C1] drm_atomic_check_only (drivers/gpu/drm/drm_atomic.c:1503)
[ 674.477808][ C1] drm_atomic_commit (drivers/gpu/drm/drm_atomic.c:1571)
[ 674.477816][ C1] ? dump_dte_entry (drivers/gpu/drm/drm_print.c:210)
[ 674.477829][ C1] drm_client_modeset_commit_atomic (drivers/gpu/drm/drm_client_modeset.c:?)
[ 674.477862][ C1] drm_client_modeset_commit_locked (drivers/gpu/drm/drm_client_modeset.c:1206)
[ 674.477874][ C1] drm_client_modeset_commit (drivers/gpu/drm/drm_client_modeset.c:1232)
[ 674.477882][ C1] __drm_fb_helper_restore_fbdev_mode_unlocked (drivers/gpu/drm/drm_fb_helper.c:?)
[ 674.477895][ C1] drm_fb_helper_set_par (drivers/gpu/drm/drm_fb_helper.c:?)
[ 674.477904][ C1] ? drm_fb_pixel_format_equal (drivers/gpu/drm/drm_fb_helper.c:1316)
[ 674.477913][ C1] fbcon_init (drivers/video/fbdev/core/fbcon.c:1153)
[ 674.477935][ C1] visual_init (drivers/tty/vt/vt.c:?)
[ 674.477949][ C1] do_bind_con_driver (drivers/tty/vt/vt.c:3916)
[ 674.477964][ C1] do_take_over_console (drivers/tty/vt/vt.c:?)
[ 674.477983][ C1] do_fbcon_takeover (drivers/video/fbdev/core/fbcon.c:589)
[ 674.477993][ C1] fbcon_fb_registered (drivers/video/fbdev/core/fbcon.c:3022)
[ 674.478005][ C1] register_framebuffer (drivers/video/fbdev/core/fbmem.c:512)
[ 674.478022][ C1] __drm_fb_helper_initial_config_and_unlock (drivers/gpu/drm/drm_fb_helper.c:1835)
[ 674.478050][ C1] drm_fbdev_client_hotplug (drivers/gpu/drm/clients/drm_fbdev_client.c:53)
[ 674.478065][ C1] drm_client_register (drivers/gpu/drm/drm_client.c:142)
[ 674.478077][ C1] drm_fbdev_client_setup (drivers/gpu/drm/clients/drm_fbdev_client.c:?)
[ 674.478090][ C1] drm_client_setup (drivers/gpu/drm/clients/drm_client_setup.c:47)
[ 674.478102][ C1] vkms_init (drivers/gpu/drm/vkms/vkms_drv.c:227)
[ 674.478116][ C1] ? vgem_init (drivers/gpu/drm/vkms/vkms_drv.c:213)
[ 674.478121][ C1] do_one_initcall (init/main.c:1269)
[ 674.478137][ C1] ? stack_depot_save_flags (lib/stackdepot.c:722)
[ 674.478153][ C1] ? kasan_save_track (arch/x86/include/asm/current.h:25 (discriminator 3) mm/kasan/common.c:60 (discriminator 3) mm/kasan/common.c:69 (discriminator 3))
[ 674.478161][ C1] ? kasan_save_track (mm/kasan/common.c:48 mm/kasan/common.c:68)
[ 674.478168][ C1] ? __kasan_kmalloc (mm/kasan/common.c:409)
[ 674.478176][ C1] ? __kmalloc_noprof (include/linux/kasan.h:260 mm/slub.c:4376 mm/slub.c:4388)
[ 674.478181][ C1] ? do_initcalls (init/main.c:1341)
[ 674.478188][ C1] ? kernel_init_freeable (init/main.c:1581)
[ 674.478193][ C1] ? kernel_init (init/main.c:1471)
[ 674.478200][ C1] ? ret_from_fork (arch/x86/kernel/process.c:154)
[ 674.478207][ C1] ? ret_from_fork_asm (arch/x86/entry/entry_64.S:258)
[ 674.478225][ C1] ? asm_sysvec_apic_timer_interrupt (arch/x86/include/asm/idtentry.h:702)
[ 674.478241][ C1] ? strlen (lib/string.c:420 (discriminator 769))
[ 674.478250][ C1] ? next_arg (lib/cmdline.c:273)
[ 674.478261][ C1] ? parameq (kernel/params.c:91 (discriminator 2048) kernel/params.c:99 (discriminator 2048))
[ 674.478263][ C1] ? parse_args (kernel/params.c:?)
[ 674.478263][ C1] do_initcall_level (init/main.c:1330 (discriminator 6))
[ 674.478263][ C1] do_initcalls (init/main.c:1344 (discriminator 2))
[ 674.478263][ C1] kernel_init_freeable (init/main.c:1581)
[ 674.478263][ C1] ? rest_init (init/main.c:1461)
[ 674.478263][ C1] kernel_init (init/main.c:1471)
[ 674.478263][ C1] ? rest_init (init/main.c:1461)
[ 674.478263][ C1] ret_from_fork (arch/x86/kernel/process.c:154)
[ 674.478341][ C1] ? rest_init (init/main.c:1461)
[ 674.478341][ C1] ret_from_fork_asm (arch/x86/entry/entry_64.S:258)
[ 674.478341][ C1] </TASK>
[ 674.478341][ C1] Kernel panic - not syncing: softlockup: hung tasks
[ 674.478341][ C1] CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Tainted: G L 6.17.0-rc6-01063-ga3ae9f413a97 #1 VOLUNTARY
[ 674.478341][ C1] Tainted: [L]=SOFTLOCKUP
[ 674.478341][ C1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 674.478341][ C1] Call Trace:
[ 674.478341][ C1] <IRQ>
[ 674.478341][ C1] vpanic (kernel/panic.c:?)
[ 674.478341][ C1] panic (??:?)
[ 674.478341][ C1] watchdog_timer_fn (kernel/watchdog.c:832)
[ 674.478341][ C1] ? softlockup_count_show (kernel/watchdog.c:733)
[ 674.478341][ C1] __hrtimer_run_queues (kernel/time/hrtimer.c:1761)
[ 674.478341][ C1] hrtimer_interrupt (kernel/time/hrtimer.c:1890)
[ 674.478341][ C1] __sysvec_apic_timer_interrupt (arch/x86/include/asm/jump_label.h:36 arch/x86/include/asm/trace/irq_vectors.h:40 arch/x86/kernel/apic/apic.c:1057)
[ 674.478341][ C1] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1050 (discriminator 24))
[ 674.478341][ C1] </IRQ>
[ 674.478341][ C1] <TASK>
[ 674.478341][ C1] asm_sysvec_apic_timer_interrupt (arch/x86/include/asm/idtentry.h:702)
[ 674.478341][ C1] RIP: 0010:__sanitizer_cov_trace_pc (arch/x86/include/asm/preempt.h:27 kernel/kcov.c:183 kernel/kcov.c:217)
[ 674.478341][ C1] Code: 48 c7 c7 00 a1 59 8a 48 89 de e8 be 1e 42 01 eb 85 cc cc cc cc cc cc cc cc cc cc cc cc 48 8b 04 24 65 48 8b 0c 25 08 30 0a 8d <65> 8b 15 dc c0 97 0b 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75
All code
========
0: 48 c7 c7 00 a1 59 8a mov $0xffffffff8a59a100,%rdi
7: 48 89 de mov %rbx,%rsi
a: e8 be 1e 42 01 call 0x1421ecd
f: eb 85 jmp 0xffffffffffffff96
11: cc int3
12: cc int3
13: cc int3
14: cc int3
15: cc int3
16: cc int3
17: cc int3
18: cc int3
19: cc int3
1a: cc int3
1b: cc int3

The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20250930/202509301358.38036b85-lkp@intel.com

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0-DAY CI Kernel Test Service