rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=f85/1/0x4000000000000000 softirq=78462/78464 fqs=3 (detected by 0, t=10502 jiffies, g=125773, q=27) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 25272 Comm: syz.6.4315 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__kasan_check_read+0x8/0x10 mm/kasan/shadow.c:31 Code: 5d c3 48 c7 c7 2f 14 df 8b eb 0a 48 c7 c7 b5 37 c5 8b 48 89 de e8 f8 6d f4 07 31 ed eb d7 00 00 cc cc 89 f6 48 8b 0c 24 31 d2 43 ef ff ff 0f 1f 00 89 f6 48 8b 0c 24 ba 01 00 00 00 e9 30 ef RSP: 0018:ffffc90000dd08f8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000015 RCX: ffffffff815d2f8a RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901d80c0 RBP: ffffc90000dd0b50 R08: dffffc0000000000 R09: 0000000000000001 R10: dffffc0000000000 R11: fffffbfff1b140de R12: ffff888023cfc690 R13: 0000000000000000 R14: 0000000000000000 R15: ffff888023cfc670 FS: 00007f02bb38c6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000364030 CR3: 000000005abce000 CR4: 00000000003506e0 DR0: 000000000000007d DR1: 0000000000000000 DR2: 0000000040000000 DR3: 0000000080000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: instrument_atomic_read include/linux/instrumented.h:71 [inline] test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline] hlock_class kernel/locking/lockdep.c:197 [inline] check_wait_context kernel/locking/lockdep.c:4686 [inline] __lock_acquire+0x52a/0x7d10 kernel/locking/lockdep.c:4962 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] advance_sched+0x6b5/0x920 net/sched/sch_taprio.c:749 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4f2/0xb70 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:lock_is_held_type+0x4c/0x190 kernel/locking/lockdep.c:5659 Code: 3d cc bd cc 03 00 0f 84 03 01 00 00 65 8b 05 7b fc 44 76 85 c0 0f 85 f4 00 00 00 65 48 8b 1d eb f2 44 76 83 bb ec 0a 00 00 00 <0f> 85 df 00 00 00 41 89 f7 49 89 fe 48 c7 04 24 00 00 00 00 9c 8f RSP: 0018:ffffc90003f87b38 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888023cfbb80 RCX: ffff888023cfbb80 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff8c31f3c0 RBP: 00000000ffffffff R08: ffffffff8d8a06ef R09: 1ffffffff1b140dd R10: dffffc0000000000 R11: fffffbfff1b140de R12: dffffc0000000000 R13: 000000000000d8ff R14: 00002000000000c0 R15: dffffc0000000000 lock_is_held include/linux/lockdep.h:287 [inline] ___might_sleep+0x9b/0x610 kernel/sched/core.c:9624 do_recvmmsg+0x56f/0x850 net/socket.c:2834 __sys_recvmmsg net/socket.c:2879 [inline] __do_sys_recvmmsg net/socket.c:2902 [inline] __se_sys_recvmmsg net/socket.c:2895 [inline] __x64_sys_recvmmsg+0x195/0x250 net/socket.c:2895 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f02bd132e59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f02bb38c028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f02bd3abfa0 RCX: 00007f02bd132e59 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004 RBP: 00007f02bd1c8d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f02bd3ac038 R14: 00007f02bd3abfa0 R15: 00007ffed19cb1a8 rcu: rcu_preempt kthread timer wakeup didn't happen for 10454 jiffies! g125773 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=85942 rcu: rcu_preempt kthread starved for 10455 jiffies! g125773 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:28016 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 25277 Comm: syz.6.4315 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x1110/0x1270 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x843/0x1120 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:2021 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4b4/0xb70 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__sanitizer_cov_trace_pc+0x58/0x60 kernel/kcov.c:216 Code: 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48 8d 7e 01 8b 89 14 16 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 3a 0f 1f 80 00 00 00 00 48 8b 04 24 65 48 8b 0d 64 26 89 7e 65 8b RSP: 0018:ffffc90004027898 EFLAGS: 00000246 RAX: ffffffff816de9a8 RBX: 0000000000000001 RCX: 0000000000080000 RDX: ffffc900128f9000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc900040279e0 R08: ffffffff901d80f7 R09: 1ffffffff203b01e R10: dffffc0000000000 R11: fffffbfff203b01f R12: ffff8880b91405c8 R13: 1ffff110172280b9 R14: ffff8880b903b3c0 R15: 0000000000000001 csd_lock_wait kernel/smp.c:440 [inline] smp_call_function_many_cond+0xbd8/0xd90 kernel/smp.c:969 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1134 __flush_tlb_multi arch/x86/include/asm/paravirt.h:87 [inline] flush_tlb_multi arch/x86/mm/tlb.c:946 [inline] flush_tlb_mm_range+0x365/0x580 arch/x86/mm/tlb.c:1034 change_protection_range mm/mprotect.c:358 [inline] change_protection+0x180f/0x1910 mm/mprotect.c:375 mprotect_fixup+0x6dc/0x800 mm/mprotect.c:497 do_mprotect_pkey+0x657/0x910 mm/mprotect.c:636 __do_sys_mprotect mm/mprotect.c:662 [inline] __se_sys_mprotect mm/mprotect.c:659 [inline] __x64_sys_mprotect+0x7c/0x90 mm/mprotect.c:659 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f02bd132e59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f02bb36b028 EFLAGS: 00000246 ORIG_RAX: 000000000000000a RAX: ffffffffffffffda RBX: 00007f02bd3ac090 RCX: 00007f02bd132e59 RDX: 0000000000000001 RSI: 000000000000f000 RDI: 0000200000000000 RBP: 00007f02bd1c8d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f02bd3ac128 R14: 00007f02bd3ac090 R15: 00007ffed19cb1a8 vkms_vblank_simulate: vblank timer overrun