vkms_vblank_simulate: vblank timer overrun rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10797/1:b..l P10704/1:b..l rcu: (detected by 0, t=10502 jiffies, g=51873, q=82 ncpus=2) task:udevd state:R running task stack:25384 pid:10704 tgid:10704 ppid:5172 task_flags:0x40014c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 9b 81 06 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90004bcf420 EFLAGS: 00000206 RAX: ae28888e44493900 RBX: 0000000000000000 RCX: ae28888e44493900 RDX: 0000000000000000 RSI: ffffffff8cf63f0a RDI: ffffffff8b3ddd60 RBP: ffffffff820d597e R08: 0000000000000000 R09: ffffffff820d597e R10: ffffc90004bcf7e0 R11: fffff52000979efe R12: 0000000000000000 R13: ffff88801eaa8658 R14: 0000000000000001 R15: 0000000000000246 rt_spin_lock+0x88/0x3e0 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:44 [inline] __pte_offset_map_lock+0x13e/0x210 mm/pgtable-generic.c:401 pte_offset_map_lock include/linux/mm.h:3133 [inline] zap_pte_range mm/memory.c:1840 [inline] zap_pmd_range mm/memory.c:1946 [inline] zap_pud_range mm/memory.c:1975 [inline] zap_p4d_range mm/memory.c:1996 [inline] unmap_page_range+0x89c/0x3c10 mm/memory.c:2017 unmap_single_vma mm/memory.c:2060 [inline] unmap_vmas+0x399/0x580 mm/memory.c:2104 exit_mmap+0x240/0xb40 mm/mmap.c:1280 __mmput+0xcb/0x3d0 kernel/fork.c:1133 exit_mm+0x1da/0x2c0 kernel/exit.c:582 do_exit+0x648/0x2300 kernel/exit.c:954 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107 __do_sys_exit_group kernel/exit.c:1118 [inline] __se_sys_exit_group kernel/exit.c:1116 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1116 x64_sys_call+0x21f7/0x2200 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f15e794d6c5 RSP: 002b:00007ffdfa984268 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00005636c5842fa0 RCX: 00007f15e794d6c5 RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000 RBP: 00005636c582e910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdfa9842b0 R14: 0000000000000000 R15: 0000000000000000 task:syz.9.1011 state:R running task stack:25160 pid:10797 tgid:10797 ppid:9458 task_flags:0x400040 flags:0x00080003 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6929 preempt_schedule_notrace+0xd1/0x110 kernel/sched/core.c:7206 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:752 rcu_read_lock include/linux/rcupdate.h:868 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xd4/0x2390 arch/x86/kernel/unwind_orc.c:479 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:758 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf7/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:311 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xfb6/0x1140 mm/page_alloc.c:2906 vfree+0x2ad/0x470 mm/vmalloc.c:3440 do_free_pages sound/core/pcm_memory.c:88 [inline] snd_pcm_lib_free_pages+0x250/0x2e0 sound/core/pcm_memory.c:495 do_hw_free sound/core/pcm_native.c:911 [inline] snd_pcm_release_substream+0x2b7/0x480 sound/core/pcm_native.c:2735 snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2396 [inline] snd_pcm_oss_release+0x147/0x250 sound/core/oss/pcm_oss.c:2575 __fput+0x45b/0xa80 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7efdda55efc9 RSP: 002b:00007ffd03eb99b8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007efdda7b7da0 RCX: 00007efdda55efc9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007efdda7b7da0 R08: 0000000000019d6c R09: 0000001c03eb9caf R10: 00000000005e271c R11: 0000000000000246 R12: 00000000000d58c2 R13: 00007efdda7b6090 R14: ffffffffffffffff R15: 00007ffd03eb9ad0 rcu: rcu_preempt kthread timer wakeup didn't happen for 10442 jiffies! g51873 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=37507 rcu: rcu_preempt kthread starved for 10443 jiffies! g51873 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:I stack:27144 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 10808 Comm: syz.8.1014 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:rdtsc_ordered arch/x86/include/asm/tsc.h:57 [inline] RIP: 0010:delay_tsc+0x71/0xc0 arch/x86/lib/delay.c:72 Code: 00 00 e8 c2 a2 d0 f6 65 8b 05 5b 59 e3 06 85 c0 74 1c f3 90 bf 01 00 00 00 e8 fb a0 d0 f6 e8 26 64 01 00 39 c5 75 0e 0f 01 f9 <66> 90 eb bd e8 26 c1 73 f6 eb dd 4c 29 fb e8 0c 64 01 00 89 c5 0f RSP: 0018:ffffc90003f57ae8 EFLAGS: 00000246 RAX: 000000004d5b39ae RBX: 00000000000055f3 RCX: 0000000000000001 RDX: 00000000000001f8 RSI: ffffffff8b3ddd40 RDI: ffffffff8b3ddd00 RBP: 0000000000000001 R08: ffffffff8ed62f77 R09: 1ffffffff1dac5ee R10: dffffc0000000000 R11: ffffffff8abf1680 R12: ffff88802f1ce930 R13: 1ffff11004730dcf R14: 000001f84d5b2fb0 R15: 0000000000000972 FS: 0000555562807500(0000) GS:ffff888126ef9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3c2347 CR3: 000000004d7c2000 CR4: 00000000003526f0 Call Trace: udelay include/asm-generic/delay.h:62 [inline] snd_timer_close_locked+0x30e/0x950 sound/core/timer.c:443 snd_timer_close+0x48/0xf0 sound/core/timer.c:476 snd_seq_timer_close+0xaa/0xf0 sound/core/seq/seq_timer.c:311 queue_delete sound/core/seq/seq_queue.c:126 [inline] snd_seq_queue_delete+0x8d/0xf0 sound/core/seq/seq_queue.c:188 delete_seq_queue sound/core/seq/oss/seq_oss_init.c:371 [inline] snd_seq_oss_release+0x1bc/0x2e0 sound/core/seq/oss/seq_oss_init.c:416 odev_release+0x51/0xa0 sound/core/seq/oss/seq_oss.c:141 __fput+0x45b/0xa80 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdcc371efc9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff5e536bd8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fdcc3977da0 RCX: 00007fdcc371efc9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007fdcc3977da0 R08: 0000000000001404 R09: 000000195e536ecf R10: 00007fdcc3977cb0 R11: 0000000000000246 R12: 00000000000d5c10 R13: 00007fdcc3976180 R14: ffffffffffffffff R15: 00007fff5e536cf0