rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=e5f4/1/0x4000000000000000 softirq=64793/64796 fqs=0 rcu: (detected by 0, t=10502 jiffies, g=61989, q=85 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 11903 Comm: syz.7.1244 Not tainted 6.14.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:lock_acquire+0x24b/0x550 kernel/locking/lockdep.c:5854 Code: 4c 89 f7 e8 87 bf 89 00 48 c7 44 24 60 00 00 00 00 9c 8f 44 24 60 42 80 3c 2b 00 74 08 4c 89 f7 e8 7a be 89 00 f6 44 24 61 02 <0f> 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e RSP: 0018:ffffc90000a18b00 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 1ffff9200014316c RCX: ffff8880601e8ae8 RDX: dffffc0000000000 RSI: ffffffff8c2ab680 RDI: ffffffff8c801a80 RBP: ffffc90000a18c48 R08: ffffffff945119f7 R09: 1ffffffff28a233e R10: dffffc0000000000 R11: fffffbfff28a233f R12: 1ffff92000143168 R13: dffffc0000000000 R14: ffffc90000a18b60 R15: 0000000000000046 FS: 00007f6b42b426c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6b42b21d58 CR3: 0000000025374000 CR4: 00000000003526f0 DR0: 0000000000002800 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: __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+0xab/0xca0 net/sched/sch_taprio.c:924 __run_hrtimer kernel/time/hrtimer.c:1801 [inline] __hrtimer_run_queues+0x59b/0xd30 kernel/time/hrtimer.c:1865 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1927 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:finish_task_switch+0x1ea/0x870 kernel/sched/core.c:5252 Code: c9 50 e8 29 2d 0c 00 48 83 c4 08 4c 89 f7 e8 fd 39 00 00 0f 1f 44 00 00 4c 89 f7 e8 70 c0 72 0a e8 bb 07 39 00 fb 48 8b 5d c0 <48> 8d bb 08 16 00 00 48 89 f8 48 c1 e8 03 49 be 00 00 00 00 00 fc RSP: 0018:ffffc900030772a8 EFLAGS: 00000286 RAX: 1ca9c9afb30b4800 RBX: ffff8880601e8000 RCX: ffffffff819d296a RDX: dffffc0000000000 RSI: ffffffff8c2aa420 RDI: ffffffff8c801a80 RBP: ffffc900030772f0 R08: ffffffff945118ff R09: 1ffffffff28a231f R10: dffffc0000000000 R11: fffffbfff28a2320 R12: 1ffff110170e7ebe R13: dffffc0000000000 R14: ffff8880b873e7c0 R15: ffff8880b873f5f0 context_switch kernel/sched/core.c:5381 [inline] __schedule+0x18c4/0x4c40 kernel/sched/core.c:6765 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6944 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6968 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x130/0x140 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock+0x18c/0x1e0 kernel/sched/wait.c:108 __unix_dgram_recvmsg+0x61a/0x1320 net/unix/af_unix.c:2456 sock_recvmsg_nosec+0x18e/0x1d0 net/socket.c:1023 ____sys_recvmsg+0x3cd/0x480 net/socket.c:2791 ___sys_recvmsg net/socket.c:2835 [inline] do_recvmmsg+0x426/0xab0 net/socket.c:2930 __sys_recvmmsg net/socket.c:3004 [inline] __do_sys_recvmmsg net/socket.c:3027 [inline] __se_sys_recvmmsg net/socket.c:3020 [inline] __x64_sys_recvmmsg+0x199/0x250 net/socket.c:3020 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6b41d8d169 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:00007f6b42b42038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f6b41fa6080 RCX: 00007f6b41d8d169 RDX: 0000000000010106 RSI: 00004000000000c0 RDI: 0000000000000003 RBP: 00007f6b41e0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f6b41fa6080 R15: 00007ffc16de5288 rcu: rcu_preempt kthread starved for 10502 jiffies! g61989 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:26104 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6857 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 6772 Comm: kworker/u8:12 Not tainted 6.14.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x1bc0/0x2d30 kernel/smp.c:885 Code: 64 24 68 75 07 e8 e0 f0 0b 00 eb 41 f3 90 48 b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00 01 00 00 00 74 1e bb f0 0b 00 eb db 44 89 e9 80 e1 07 80 c1 03 38 c1 7c e2 4c 89 RSP: 0018:ffffc90002e77640 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 1ffff110170e88c9 RCX: ffff88802ce73c00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90002e77840 R08: ffffffff81b5ccb0 R09: 1ffffffff28a2308 R10: dffffc0000000000 R11: fffffbfff28a2309 R12: ffff8880b863f9c8 R13: ffff8880b8744648 R14: ffff8880b863f9c0 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30314ff8 CR3: 000000000e938000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 00000000ffff000b DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2118 [inline] text_poke_bp_batch+0x352/0xb30 arch/x86/kernel/alternative.c:2328 text_poke_flush arch/x86/kernel/alternative.c:2519 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2526 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x136/0x260 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xbc/0x260 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3317 worker_thread+0x870/0xd30 kernel/workqueue.c:3398 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244