rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P27570/1:b..l rcu: (detected by 1, t=10502 jiffies, g=234625, q=741 ncpus=2) task:syz.6.5674 state:X running task stack:26136 pid:27570 tgid:27564 ppid:0 task_flags:0x40054c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7188 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7512 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x14f/0x730 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0xd/0x3c0 kernel/locking/lockdep.c:5876 Code: 00 00 00 e9 0e ff ff ff 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 41 57 41 56 41 55 41 54 <53> 48 83 ec 30 49 89 f5 49 89 fe 65 48 8b 05 a0 c3 9e 11 48 89 44 RSP: 0018:ffffc9000429fa70 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff823a1ac9 RCX: 0000000080000001 RDX: 000000005a44979c RSI: ffffffff823a1ac9 RDI: ffffffff8e95cce0 RBP: ffffc9000429fc30 R08: ffffffff823a1ac9 R09: ffffffff8e95cce0 R10: dffffc0000000000 R11: ffffed10038de4b9 R12: 1ffff1100f7bdcf4 R13: dffffc0000000000 R14: ffff888030522b80 R15: dffffc0000000000 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:869 [inline] percpu_ref_put_many include/linux/percpu-refcount.h:337 [inline] percpu_ref_put+0xf9/0x180 include/linux/percpu-refcount.h:351 memcg_kmem_uncharge_page include/linux/memcontrol.h:1735 [inline] exit_task_stack_account+0x11a/0x320 kernel/fork.c:511 do_exit+0x18b1/0x22c0 kernel/exit.c:1008 do_group_exit+0x21b/0x2d0 kernel/exit.c:1117 get_signal+0x1284/0x1330 kernel/signal.c:3037 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdb6ed9c819 RSP: 002b:00007fdb6cff6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: 00000000004dcfc0 RBX: 00007fdb6f016090 RCX: 00007fdb6ed9c819 RDX: 00000000fffffdab RSI: 0000200000000040 RDI: 0000000000000009 RBP: 00007fdb6ee32c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdb6f016128 R14: 00007fdb6f016090 R15: 00007fdb6f13fa48 rcu: rcu_preempt kthread starved for 10496 jiffies! g234625 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:27536 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0x164/0x360 kernel/sched/core.c:7282 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 1 UID: 0 PID: 27611 Comm: syz.6.5687 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xfcf/0x13d0 kernel/smp.c:892 Code: 79 45 8b 2e 44 89 ee 83 e6 01 31 ff e8 fa fc 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 a5 f8 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 8a f8 0b RSP: 0018:ffffc9000d457580 EFLAGS: 00000293 RAX: ffffffff81b9d866 RBX: ffff8880b873c148 RCX: ffff888027505c40 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000d4576c0 R08: ffffffff903380f7 R09: 1ffffffff206701e R10: dffffc0000000000 R11: fffffbfff206701f R12: 1ffff110170c8589 R13: dffffc0000000000 R14: ffff8880b8642c48 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125314000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3e927e7158 CR3: 000000004b3d6000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x5c3/0x10b0 arch/x86/mm/tlb.c:1451 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:509 [inline] tlb_flush_mmu+0x1af/0xa30 mm/mmu_gather.c:423 tlb_finish_mmu+0xf9/0x230 mm/mmu_gather.c:549 exit_mmap+0x498/0x9e0 mm/mmap.c:1313 __mmput+0x118/0x430 kernel/fork.c:1178 exit_mm+0x18e/0x250 kernel/exit.c:581 do_exit+0x6a2/0x22c0 kernel/exit.c:963 do_group_exit+0x21b/0x2d0 kernel/exit.c:1117 get_signal+0x1284/0x1330 kernel/signal.c:3037 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdb6ed9c819 Code: Unable to access opcode bytes at 0x7fdb6ed9c7ef. RSP: 002b:00007fdb6fb6e0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fdb6f015fa8 RCX: 00007fdb6ed9c819 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fdb6f015fa8 RBP: 00007fdb6f015fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdb6f016038 R14: 00007fdb6f13f960 R15: 00007fdb6f13fa48