rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (2 ticks this GP) idle=655c/1/0x4000000000000000 softirq=24094/24094 fqs=19 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5842/1:b..l rcu: (detected by 0, t=10506 jiffies, g=20625, q=274 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6778 Comm: syz.3.240 Not tainted 6.16.0-rc3-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:memset_orig+0x75/0xb0 arch/x86/lib/memset_64.S:92 Code: 89 47 30 48 89 47 38 48 8d 7f 40 75 d8 0f 1f 84 00 00 00 00 00 89 d1 83 e1 38 74 14 c1 e9 03 66 0f 1f 44 00 00 ff c9 48 89 07 <48> 8d 7f 08 75 f5 83 e2 07 74 0a ff ca 88 07 48 8d 7f 01 75 f6 4c RSP: 0018:ffffc90000a08ce8 EFLAGS: 00000002 RAX: 0000000000000000 RBX: 1ffff110170e4f01 RCX: 0000000000000001 RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffff88802f6a4348 RBP: ffff88807a3a1340 R08: ffff88802f6a4357 R09: 0000000000000000 R10: ffff88802f6a4348 R11: ffffed1005ed486b R12: ffff88802f6a4340 R13: dffffc0000000000 R14: 0000000000000001 R15: ffff88807a3a1350 FS: 00007f85b75856c0(0000) GS:ffff888125d51000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000002d3000 CR3: 000000002728a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rb_link_node include/linux/rbtree.h:63 [inline] rb_add_cached include/linux/rbtree.h:182 [inline] timerqueue_add+0x149/0x200 lib/timerqueue.c:40 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 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+0xa8/0x110 kernel/locking/spinlock.c:194 Code: 74 05 e8 3b f4 5e f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 13 df 27 f6 65 8b 05 fc 0a 34 07 85 c0 74 40 48 c7 04 24 0e 36 RSP: 0018:ffffc9001c6f7560 EFLAGS: 00000206 RAX: aa40ce0287c9ab00 RBX: 0000000000000a06 RCX: aa40ce0287c9ab00 RDX: 0000000000000006 RSI: ffffffff8d981f99 RDI: 0000000000000001 RBP: ffffc9001c6f75f8 R08: ffffffff8fa10af7 R09: 1ffffffff1f4215e R10: dffffc0000000000 R11: fffffbfff1f4215f R12: dffffc0000000000 R13: 1ffff11004e7e765 R14: ffff8880273f3ac0 R15: 1ffff920038deeac spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __skb_try_recv_datagram+0x17c/0x4e0 net/core/datagram.c:267 __unix_dgram_recvmsg+0x2d5/0xde0 net/unix/af_unix.c:2503 sock_recvmsg_nosec+0x183/0x1c0 net/socket.c:1017 ____sys_recvmsg+0x3aa/0x460 net/socket.c:2784 ___sys_recvmsg+0x1b5/0x510 net/socket.c:2828 do_recvmmsg+0x307/0x770 net/socket.c:2923 __sys_recvmmsg net/socket.c:2997 [inline] __do_sys_recvmmsg net/socket.c:3020 [inline] __se_sys_recvmmsg net/socket.c:3013 [inline] __x64_sys_recvmmsg+0x190/0x240 net/socket.c:3013 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f85b678e929 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:00007f85b7585038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f85b69b6080 RCX: 00007f85b678e929 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000006 RBP: 00007f85b6810b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f85b69b6080 R15: 00007f85b6adfa28 task:syz-executor state:R running task stack:21832 pid:5842 tgid:5842 ppid:5822 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6965 preempt_schedule+0xae/0xc0 kernel/sched/core.c:6989 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+0x3f/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+0x6727/0x7000 mm/memory.c:1267 copy_pud_range mm/memory.c:1304 [inline] copy_p4d_range mm/memory.c:1328 [inline] copy_page_range+0xc46/0x1270 mm/memory.c:1416 dup_mmap+0xf57/0x1ac0 mm/mmap.c:1838 dup_mm kernel/fork.c:1477 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1529 copy_process+0x1706/0x3c00 kernel/fork.c:2169 kernel_clone+0x21e/0x870 kernel/fork.c:2599 __do_sys_clone kernel/fork.c:2742 [inline] __se_sys_clone kernel/fork.c:2726 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2726 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f963f785193 RSP: 002b:00007f963fadfca8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f963f785193 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000555565acc7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 0000000000029a62 R15: 00007f963fadfe40 rcu: rcu_preempt kthread starved for 10412 jiffies! g20625 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:27080 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 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: CPU: 0 UID: 0 PID: 36 Comm: kworker/u8:2 Not tainted 6.16.0-rc3-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xf69/0x12d0 kernel/smp.c:885 Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 70 78 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 1b 74 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 00 74 0b RSP: 0018:ffffc90000ac76a0 EFLAGS: 00000293 RAX: ffffffff81b4d920 RBX: ffff8880b863b1c0 RCX: ffff88801dabda00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000ac7800 R08: ffffffff8fa10af7 R09: 1ffffffff1f4215e R10: dffffc0000000000 R11: fffffbfff1f4215f R12: 1ffff110170e7f5d R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b873fae8 FS: 0000000000000000(0000) GS:ffff888125c51000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f067c82adfa CR3: 000000000df38000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2691 [inline] smp_text_poke_batch_finish+0x5e0/0x1100 arch/x86/kernel/alternative.c:2901 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 vkms_vblank_simulate: vblank timer overrun