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): P16459/1:b..l P15122/1:b..l P49/1:b..l rcu: (detected by 1, t=10502 jiffies, g=128601, q=155 ncpus=2) task:kworker/u4:3 state:R running task stack:22632 pid:49 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_notrace+0xdd/0x110 kernel/sched/core.c:6960 preempt_schedule_notrace_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:46 rcu_is_watching+0x7a/0xb0 kernel/rcu/tree.c:701 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0xc6/0x420 kernel/locking/lockdep.c:5725 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] batadv_nc_process_nc_paths+0xdb/0x390 net/batman-adv/network-coding.c:687 batadv_nc_worker+0x429/0x610 net/batman-adv/network-coding.c:728 process_one_work kernel/workqueue.c:2653 [inline] process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 task:syz-executor state:R running task stack:21416 pid:15122 ppid:15102 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:check_kcov_mode kernel/kcov.c:193 [inline] RIP: 0010:write_comp_data kernel/kcov.c:245 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x36/0x80 kernel/kcov.c:320 Code: 50 91 7c 7e 65 8b 15 51 91 7c 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 57 83 b9 1c 16 00 00 00 74 4e 8b 91 f8 15 00 00 <83> fa 03 75 43 48 8b 91 00 16 00 00 44 8b 89 fc 15 00 00 49 c1 e1 RSP: 0018:ffffc90003117758 EFLAGS: 00000246 RAX: ffffffff81b5c2ff RBX: ffffea000159dfc0 RCX: ffff88802b330000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 1ffffd40002b3bf9 R08: ffffea000159dfc7 R09: 1ffffd40002b3bf8 R10: dffffc0000000000 R11: fffff940002b3bf9 R12: 0000000000000027 R13: 1ffffd40002b3bf8 R14: 0000000000000027 R15: ffffea000159df88 PageTail include/linux/page-flags.h:285 [inline] folio_flags include/linux/page-flags.h:312 [inline] folio_test_head include/linux/page-flags.h:798 [inline] folio_test_large include/linux/page-flags.h:819 [inline] folio_nr_pages include/linux/mm.h:2056 [inline] folio_contains+0x20f/0x5c0 include/linux/pagemap.h:845 find_lock_entries+0x66c/0xfe0 mm/filemap.c:2125 shmem_undo_range+0x2b3/0x1b20 mm/shmem.c:1008 shmem_truncate_range mm/shmem.c:1135 [inline] shmem_evict_inode+0x245/0x9e0 mm/shmem.c:1264 evict+0x4ca/0x8d0 fs/inode.c:705 do_unlinkat+0x38c/0x590 fs/namei.c:4406 __do_sys_unlink fs/namei.c:4447 [inline] __se_sys_unlink fs/namei.c:4445 [inline] __x64_sys_unlink+0x49/0x50 fs/namei.c:4445 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f51e4f9b907 RSP: 002b:00007fff34860498 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f51e4f9b907 RDX: 00007fff348604c0 RSI: 00007fff34860550 RDI: 00007fff34860550 RBP: 00007fff34860550 R08: 00007fff34861550 R09: 00000000ffffffff R10: 0000000000000100 R11: 0000000000000206 R12: 00007fff348615e0 R13: 00007f51e5032048 R14: 000000000011095b R15: 00007fff34861620 task:syz.2.2844 state:R running task stack:24232 pid:16459 ppid:14812 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] insert_page mm/memory.c:1869 [inline] vm_insert_page+0x57c/0x8c0 mm/memory.c:2021 kcov_mmap+0xe9/0x160 kernel/kcov.c:505 call_mmap include/linux/fs.h:2023 [inline] mmap_file mm/internal.h:98 [inline] __mmap_region mm/mmap.c:2790 [inline] mmap_region+0xf8e/0x2000 mm/mmap.c:2941 do_mmap+0x92c/0x10a0 mm/mmap.c:1385 vm_mmap_pgoff+0x1c4/0x3f0 mm/util.c:556 ksys_mmap_pgoff+0x520/0x700 mm/mmap.c:1431 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7eff6d99c582 RSP: 002b:00007ffcdba00958 EFLAGS: 00000206 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007eff6b7f6000 RCX: 00007eff6d99c582 RDX: 0000000000000003 RSI: 0000000000400000 RDI: 00007eff6b7f6000 RBP: 0000000000000011 R08: 00000000000000db R09: 0000000000000000 R10: 0000000000000011 R11: 0000000000000206 R12: 0000000000000003 R13: 0000000000000003 R14: 0000000000000000 R15: 00007eff6dc15fa0 rcu: rcu_preempt kthread starved for 10511 jiffies! g128601 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27184 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148 Code: 6f 21 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d 23 39 42 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80 RSP: 0018:ffffffff8ce07d80 EFLAGS: 000002c6 RAX: 12734ad17b325800 RBX: ffffffff8162a8c1 RCX: 12734ad17b325800 RDX: 0000000000000001 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c89a0 RBP: ffffffff8ce07eb8 R08: ffff8880b8e36b2b R09: 1ffff110171c6d65 R10: dffffc0000000000 R11: ffffed10171c6d66 R12: 1ffffffff19c0fbc R13: dffffc0000000000 R14: 1ffffffff19d2688 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2a9ed48019 CR3: 000000002d55e000 CR4: 00000000003506f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:753 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:178 [inline] do_idle+0x221/0x590 kernel/sched/idle.c:302 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401 rest_init+0x2e2/0x300 init/main.c:744 arch_call_rest_init+0xe/0x10 init/main.c:841 start_kernel+0x459/0x4e0 init/main.c:1086 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b