rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=fd6c/1/0x4000000000000000 softirq=26518/26518 fqs=4 rcu: (detected by 1, t=10502 jiffies, g=18733, q=561 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6550 Comm: sed Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:__asan_memset+0x0/0x50 mm/kasan/shadow.c:83 Code: 48 8b 0c 24 ba 01 00 00 00 e9 bc e4 ff ff 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 55 41 56 53 48 89 d3 89 f5 49 89 fe 48 8b 4c 24 18 48 RSP: 0000:ffffc90003a87c28 EFLAGS: 00000046 RAX: ffffffff8b766747 RBX: 1ffff110170c4f7a RCX: ffff888020b68000 RDX: 0000000000000018 RSI: 0000000000000000 RDI: ffff888027bd6340 RBP: 0000000000000000 R08: ffffffff8fa3a737 R09: 1ffffffff1f474e6 R10: dffffc0000000000 R11: fffffbfff1f474e7 R12: ffff888027bd6340 R13: dffffc0000000000 R14: ffff8880b8627bd0 R15: ffff888027bd6340 FS: 00007ff1792dcc80(0000) GS:ffff888125c13000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff1794b0a90 CR3: 00000000576c8000 CR4: 0000000000350ef0 Call Trace: rb_link_node include/linux/rbtree.h:63 [inline] rb_add_cached include/linux/rbtree.h:182 [inline] timerqueue_add+0x186/0x200 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+0x52/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0033:0x7ff17965a073 Code: 03 42 08 48 8b 93 38 03 00 00 49 89 c7 48 85 d2 0f 84 09 01 00 00 8b 8b 34 03 00 00 8b 44 24 18 23 83 30 03 00 00 48 8b 04 c2 <44> 89 c2 d3 ea 89 d1 48 89 c2 48 d3 ea 44 89 c1 48 d3 e8 48 21 c2 RSP: 002b:00007ffe145dd280 EFLAGS: 00000206 RAX: 0244c54000000180 RBX: 00007ff1796475f0 RCX: 000000000000000f RDX: 00007ff1793a94b0 RSI: 00007ff1793ae580 RDI: 00000000000003f1 RBP: 00007ff179648e50 R08: 000000007dd7aaaa R09: 0000000000000000 R10: 000000000000000a R11: 00007ff179648ab0 R12: 0000000000000000 R13: 00007ff17934acc8 R14: 000000007dd7aaaa R15: 00007ff1793c0dd8 rcu: rcu_preempt kthread starved for 10494 jiffies! g18733 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:26792 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 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: 1 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216 Code: 8b 3d 64 87 fe 0b 48 89 de 5b e9 f3 ab 58 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0c 25 08 d0 a0 92 65 8b 15 88 22 e1 10 81 e2 00 01 ff 00 RSP: 0018:ffffc90000127658 EFLAGS: 00000202 RAX: ffffffff81b44e7b RBX: 1ffff110170c8341 RCX: ffff88801ceb8000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900001277e0 R08: ffffffff8fa3a737 R09: 1ffffffff1f474e6 R10: dffffc0000000000 R11: fffffbfff1f474e7 R12: ffff8880b8641a08 R13: dffffc0000000000 R14: ffff8880b873b1c0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125d13000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3efdbcfe9c CR3: 000000000df36000 CR4: 0000000000350ef0 Call Trace: csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0xd4b/0x12d0 kernel/smp.c:877 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2653 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2863 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:3236 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 sched: DL replenish lagged too much