rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=0b1c/1/0x4000000000000000 softirq=164051/164053 fqs=1 rcu: (detected by 1, t=10506 jiffies, g=246157, q=438 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 19 Comm: rcu_exp_gp_kthr Not tainted 6.11.0-rc2-syzkaller-00004-gb446a2dae984 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 RIP: 0010:check_wait_context kernel/locking/lockdep.c:4795 [inline] RIP: 0010:__lock_acquire+0x803/0x2040 kernel/locking/lockdep.c:5092 Code: 48 8b 44 24 58 0f b6 04 10 84 c0 0f 85 66 14 00 00 48 8b 44 24 18 83 38 00 0f 94 c3 00 db 80 c3 02 48 8b 44 24 38 0f b6 04 10 <84> c0 0f 85 9c 12 00 00 89 5c 24 08 45 3b 65 00 0f 8d ad 02 00 00 RSP: 0018:ffffc90000007a30 EFLAGS: 00000002 RAX: 0000000000000000 RBX: 0000000000085002 RCX: 0000000000000002 RDX: dffffc0000000000 RSI: ffff8880182dc6e0 RDI: 0000000000000005 RBP: 0000000000000000 R08: ffffffff9372ca1f R09: 1ffffffff26e5943 R10: dffffc0000000000 R11: fffffbfff26e5944 R12: 0000000000000001 R13: ffff8880182dc6d8 R14: 1ffff1100305b8e5 R15: ffff8880182dc728 FS: 0000000000000000(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32f05ff8 CR3: 0000000069c18000 CR4: 0000000000350ef0 Call Trace: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759 __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:1689 [inline] __hrtimer_run_queues+0x59d/0xd50 kernel/time/hrtimer.c:1753 hrtimer_interrupt+0x396/0x990 kernel/time/hrtimer.c:1815 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline] __sysvec_apic_timer_interrupt+0x112/0x3f0 arch/x86/kernel/apic/apic.c:1049 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline] RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline] RIP: 0010:rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline] RIP: 0010:rcu_is_watching+0x5a/0xb0 kernel/rcu/tree.c:726 Code: f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 cc fe 80 00 48 c7 c3 78 7c 03 00 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 75 22 8b 03 65 ff 0d 71 25 8a 7e 74 10 83 e0 04 c1 e8 02 5b RSP: 0018:ffffc90000187a20 EFLAGS: 00000212 RAX: 0000000000000000 RBX: ffff8880b9237c78 RCX: ffffffff816fe2c0 RDX: 0000000000000000 RSI: ffffffff8c605ce0 RDI: ffffffff8c605ca0 RBP: ffffc90000187b70 R08: ffffffff9017c16f R09: 1ffffffff202f82d R10: dffffc0000000000 R11: fffffbfff202f82e R12: 1ffff92000030f54 R13: ffffffff817a73e9 R14: ffffffff8e293a40 R15: dffffc0000000000 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0xbf/0xa30 kernel/locking/lockdep.c:5770 __mutex_unlock_slowpath+0xe2/0x750 kernel/locking/mutex.c:912 rcu_exp_wait_wake kernel/rcu/tree_exp.h:681 [inline] rcu_exp_sel_wait_wake+0x1989/0x1db0 kernel/rcu/tree_exp.h:694 kthread_worker_fn+0x502/0xaf0 kernel/kthread.c:842 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: rcu_preempt kthread starved for 10500 jiffies! g246157 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:24912 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6621 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2034 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2236 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 62 Comm: kworker/u8:4 Not tainted 6.11.0-rc2-syzkaller-00004-gb446a2dae984 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:312 [inline] RIP: 0010:smp_call_function_many_cond+0x1865/0x29d0 kernel/smp.c:856 Code: 89 e6 83 e6 01 31 ff e8 99 14 0c 00 41 83 e4 01 49 bc 00 00 00 00 00 fc ff df 75 07 e8 44 10 0c 00 eb 38 f3 90 42 0f b6 04 23 <84> c0 75 11 41 f7 45 00 01 00 00 00 74 1e e8 28 10 0c 00 eb e4 44 RSP: 0018:ffffc900015d7700 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff11017248c61 RCX: ffff888017be3c00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900015d78e0 R08: ffffffff81876697 R09: 1ffffffff26e5900 R10: dffffc0000000000 R11: fffffbfff26e5901 R12: dffffc0000000000 R13: ffff8880b9246308 R14: ffff8880b933fb80 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b9300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f169b8356c0 CR3: 000000000e734000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1023 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2085 [inline] text_poke_bp_batch+0x352/0xb30 arch/x86/kernel/alternative.c:2295 text_poke_flush arch/x86/kernel/alternative.c:2486 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2493 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+0xb5/0x250 mm/kfence/core.c:833 process_one_work kernel/workqueue.c:3231 [inline] process_scheduled_works+0xa2e/0x1830 kernel/workqueue.c:3312 worker_thread+0x86d/0xd40 kernel/workqueue.c:3390 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244