rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=c14c/1/0x4000000000000000 softirq=33040/33040 fqs=0 rcu: (detected by 0, t=10506 jiffies, g=39193, q=120 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 9628 Comm: syz.4.1260 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:__sanitizer_cov_trace_cmp8+0x0/0x20 kernel/kcov.c:293 Code: 0c 24 89 f2 89 fe bf 04 00 00 00 e9 ea fe ff ff 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 48 8b 0c 24 48 89 f2 48 89 fe bf 06 00 00 00 e9 b8 fe RSP: 0018:ffffc90000a08e80 EFLAGS: 00000046 RAX: 1ffff1100a22ee68 RBX: 18b35ce7b9fe45f7 RCX: ffffffff81f46739 RDX: ffff88804f1ea500 RSI: 18b35ce7b9fe45f7 RDI: 3680c02067fa4ef1 RBP: ffff8880b8528600 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffff888051177300 R13: 0000000000000001 R14: dffffc0000000000 R15: 3680c02067fa4ef1 FS: 00007f32b8dfd6c0(0000) GS:ffff88812446a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000007a979000 CR4: 00000000003526f0 Call Trace: __hrtimer_run_queues+0x296/0xa00 kernel/time/hrtimer.c:1991 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 a6 4f 56 f6 48 89 df e8 7e 9f 56 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 a5 6b 46 f6 65 8b 05 fe 1e 7d 08 85 c0 74 16 5b RSP: 0018:ffffc90010477b48 EFLAGS: 00000246 RAX: 0000000000000002 RBX: ffff8880b85284c0 RCX: 0000000000000080 RDX: 0000000000000000 RSI: ffffffff8df2430b RDI: ffffffff8c1c4400 RBP: 0000000000000287 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: fffffbfff21afd0a R13: dffffc0000000000 R14: e2329b39f3e7e70c R15: 0000000000000002 class_raw_spinlock_irqsave_destructor include/linux/spinlock.h:571 [inline] clock_was_set+0x5d9/0x870 kernel/time/hrtimer.c:994 do_adjtimex+0x302/0x370 kernel/time/timekeeping.c:2924 do_clock_adjtime kernel/time/posix-timers.c:1154 [inline] __do_sys_clock_adjtime+0x177/0x290 kernel/time/posix-timers.c:1166 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0x860 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f32b7f9ce59 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:00007f32b8dfd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00007f32b8215fa0 RCX: 00007f32b7f9ce59 RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000000 RBP: 00007f32b8032d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f32b8216038 R14: 00007f32b8215fa0 R15: 00007ffed6e4c7a8 rcu: rcu_preempt kthread starved for 10506 jiffies! g39193 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:28216 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 9636 Comm: syz.1.1264 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x589/0x1700 kernel/smp.c:892 Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 39 84 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31 RSP: 0018:ffffc90010467a80 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fc2b4d RDX: ffff888033078000 RSI: ffffffff81fc2b27 RDI: ffff888033078000 RBP: ffff8880b8540f40 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170a81e9 R14: 0000000000000001 R15: ffff8880b843c5c0 FS: 00007fef6c4926c0(0000) GS:ffff88812436a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000140 CR3: 00000000933ff000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057 on_each_cpu include/linux/smp.h:72 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline] smp_text_poke_batch_finish+0x337/0xc60 arch/x86/kernel/alternative.c:2983 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x37a/0x550 kernel/jump_label.c:910 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 __sched_core_enable kernel/sched/core.c:475 [inline] sched_core_get+0x8a/0xa0 kernel/sched/core.c:499 sched_core_alloc_cookie kernel/sched/core_sched.c:20 [inline] sched_core_share_pid+0x406/0x9d0 kernel/sched/core_sched.c:187 __do_sys_prctl+0x6bd/0x2310 kernel/sys.c:2808 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0x860 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fef6b59ce59 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:00007fef6c492028 EFLAGS: 00000246 ORIG_RAX: 000000000000009d RAX: ffffffffffffffda RBX: 00007fef6b815fa0 RCX: 00007fef6b59ce59 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 000000000000003e RBP: 00007fef6b632d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fef6b816038 R14: 00007fef6b815fa0 R15: 00007ffed65455e8