rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10499 ticks this GP) idle=6924/0/0x1 softirq=23112/23112 fqs=0 (t=10501 jiffies g=31297 q=11 ncpus=2) rcu: rcu_preempt kthread starved for 10502 jiffies! g31297 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27840 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 6067 Comm: syz.5.378 Not tainted 6.1.141-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:rcu_preempt_read_enter kernel/rcu/tree_plugin.h:379 [inline] RIP: 0010:__rcu_read_lock+0x10/0x50 kernel/rcu/tree_plugin.h:402 Code: f1 80 e1 07 38 c1 0f 8c 01 fb ff ff 4c 89 f7 e8 96 80 66 00 e9 f4 fa ff ff 90 53 65 48 8b 1d 77 a0 96 7e 48 81 c3 3c 04 00 00 <48> 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 RSP: 0018:ffffc900001e0c40 EFLAGS: 00000082 RAX: ffffffff815086c8 RBX: ffff888030a13fbc RCX: 0000000000010000 RDX: ffff888030a13b80 RSI: 0000000000000001 RDI: 0000000000000000 RBP: dffffc0000000000 R08: 0000000000000004 R09: 0000000000000003 R10: fffff5200003c174 R11: 1ffff9200003c174 R12: ffff88807282b328 R13: ffff88807107f3c0 R14: ffff88807282b310 R15: 0000000000000001 FS: 00007f8c4499c6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000005fe24000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock include/linux/rcupdate.h:789 [inline] send_sigqueue+0x86/0x600 kernel/signal.c:1977 posix_timer_event kernel/time/posix-timers.c:360 [inline] posix_timer_fn+0x16a/0x3d0 kernel/time/posix-timers.c:386 __run_hrtimer kernel/time/hrtimer.c:1752 [inline] __hrtimer_run_queues+0x554/0xd60 kernel/time/hrtimer.c:1816 hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1878 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 de d0 49 f7 48 89 df e8 36 96 4a f7 e8 31 97 6d f7 fb bf 01 00 00 00 46 13 3e f7 65 8b 05 17 d4 e8 75 85 c0 74 02 5b c3 e8 64 e5 e6 RSP: 0018:ffffc90003267bb8 EFLAGS: 00000286 RAX: ffc59440ecb3bd00 RBX: ffff8880742e1bc0 RCX: ffc59440ecb3bd00 RDX: dffffc0000000000 RSI: ffffffff8a6bffe0 RDI: 0000000000000001 RBP: ffff8880742e1e58 R08: dffffc0000000000 R09: ffffed100e85c379 R10: ffffed100e85c379 R11: 1ffff1100e85c378 R12: 1ffff1100e85c3cb R13: 0000000000000011 R14: dffffc0000000000 R15: 0000000000000000 spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x1163/0x1350 kernel/signal.c:2874 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f8c43b8e929 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:00007f8c4499c0e8 EFLAGS: 00000246 RAX: fffffffffffffffc RBX: 00007f8c43db5fa8 RCX: 00007f8c43b8e929 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f8c43db5fa8 RBP: 00007f8c43db5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8c43db5fac R13: 0000000000000000 R14: 00007ffc8159da30 R15: 00007ffc8159db18 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.141-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:736 Code: 48 89 df e8 47 d4 b8 f7 e9 4c ff ff ff e8 bd 15 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d 17 24 4d 00 fb f4 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48 RSP: 0018:ffffffff8c607d88 EFLAGS: 000002c6 RAX: 1ad313cdb5794300 RBX: ffffffff8a197f77 RCX: 1ad313cdb5794300 RDX: 0000000000000001 RSI: ffffffff8a6bffe0 RDI: ffffffff8abf1360 RBP: ffffffff8c607ec0 R08: dffffc0000000000 R09: ffffed10171c6af6 R10: ffffed10171c6af6 R11: 1ffff110171c6af5 R12: 0000000000000000 R13: dffffc0000000000 R14: ffffffff8c6bc680 R15: 1ffffffff1bfd0f6 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c26506c CR3: 000000005fe24000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: default_idle_call+0x84/0xc0 kernel/sched/idle.c:109 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1fc/0x570 kernel/sched/idle.c:303 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:401 rest_init+0x2dc/0x300 init/main.c:733 arch_call_rest_init+0xa/0xa init/main.c:893 start_kernel+0x490/0x539 init/main.c:1140 secondary_startup_64_no_verify+0xcf/0xdb