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): P8915/1:b..l P7933/1:b..l rcu: (detected by 1, t=10502 jiffies, g=25961, q=705 ncpus=2) task:syz-executor state:R running task stack:24360 pid:7933 tgid:7933 ppid:7915 task_flags:0x400140 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6965 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1206 [inline] copy_pmd_range mm/memory.c:1267 [inline] copy_pud_range mm/memory.c:1304 [inline] copy_p4d_range mm/memory.c:1328 [inline] copy_page_range+0x2113/0x5d90 mm/memory.c:1416 dup_mmap+0xe88/0x21d0 mm/mmap.c:1838 dup_mm kernel/fork.c:1477 [inline] copy_mm kernel/fork.c:1529 [inline] copy_process+0x4081/0x76a0 kernel/fork.c:2169 kernel_clone+0xfc/0x960 kernel/fork.c:2599 __do_sys_clone+0xce/0x120 kernel/fork.c:2742 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4467785193 RSP: 002b:00007fff743c28d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4467785193 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 000055559526c7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 000000000005a6c5 R15: 00007fff743c2a70 task:syz.1.721 state:R running task stack:27672 pid:8915 tgid:8914 ppid:5827 task_flags:0x40044c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6965 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1765 [inline] zap_pmd_range mm/memory.c:1827 [inline] zap_pud_range mm/memory.c:1856 [inline] zap_p4d_range mm/memory.c:1877 [inline] unmap_page_range+0x109c/0x4380 mm/memory.c:1898 unmap_single_vma.constprop.0+0x153/0x240 mm/memory.c:1941 unmap_vmas+0x218/0x470 mm/memory.c:1985 exit_mmap+0x1b9/0xb90 mm/mmap.c:1284 __mmput+0x12a/0x410 kernel/fork.c:1121 mmput+0x62/0x70 kernel/fork.c:1144 exit_mm kernel/exit.c:581 [inline] do_exit+0x7bc/0x2bd0 kernel/exit.c:943 do_group_exit+0xd3/0x2a0 kernel/exit.c:1104 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:111 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa4f778e929 RSP: 002b:00007fa4f85a4038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: fffffffffffffe00 RBX: 00007fa4f79b5fa0 RCX: 00007fa4f778e929 RDX: 0000000000000010 RSI: 0000200000000180 RDI: 0000000000000004 RBP: 00007fa4f7810b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fa4f79b5fa0 R15: 00007ffcc2953d18 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g25961 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=17102 rcu: rcu_preempt kthread starved for 10502 jiffies! g25961 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 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:27672 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6878 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5189 Comm: udevd Not tainted 6.15.0-syzkaller-12426-ge271ed52b344 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:its_return_thunk+0x0/0x10 arch/x86/lib/retpoline.S:412 Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 e9 db fc a9 f5 cc RSP: 0018:ffffc90000007d00 EFLAGS: 00000086 RAX: 0000000000000000 RBX: ffff88802da1b300 RCX: ffffffff93e97840 RDX: 0000000000000000 RSI: ffffffff8ddef823 RDI: ffffffff8c157060 RBP: 0000000000000000 R08: 393929a7d321714f R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f64ecd66880(0000) GS:ffff88812475a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fddced8c840 CR3: 0000000022add000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:473 [inline] lock_acquire kernel/locking/lockdep.c:5873 [inline] lock_acquire+0x189/0x350 kernel/locking/lockdep.c:5828 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] advance_sched+0xd9/0xc80 net/sched/sch_taprio.c:924 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x202/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 16 c1 16 f6 48 89 df e8 fe 14 17 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 35 35 07 f6 65 8b 05 0e aa 4a 08 85 c0 74 16 5b RSP: 0018:ffffc90003327900 EFLAGS: 00000246 RAX: 0000000000000006 RBX: ffff88805b2b9240 RCX: ffffffff81c3e5ef RDX: 0000000000000000 RSI: ffffffff8de14dcb RDI: ffffffff8c157060 RBP: 0000000000000282 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff90a80057 R11: 0000000000000001 R12: ffff888036bfb180 R13: ffff88805b2b9240 R14: ffff888036bfb558 R15: ffff88804a6cfdc0 sock_def_readable+0x15b/0x600 net/core/sock.c:3583 __netlink_sendskb net/netlink/af_netlink.c:1259 [inline] netlink_sendskb net/netlink/af_netlink.c:1265 [inline] netlink_unicast+0x6ef/0x7f0 net/netlink/af_netlink.c:1354 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0xa95/0xc70 net/socket.c:2566 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620 __sys_sendmsg+0x16d/0x220 net/socket.c:2652 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f64ec6a7407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007fffab3bf360 EFLAGS: 00000202 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f64ecd66880 RCX: 00007f64ec6a7407 RDX: 0000000000000000 RSI: 00007fffab3bf3c0 RDI: 0000000000000004 RBP: 00005589923fc250 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000000b3 R13: 00005589921bfd80 R14: 0000000000000000 R15: 0000000000000000