rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=052c/1/0x4000000000000000 softirq=121328/121330 fqs=1 rcu: (detected by 1, t=10502 jiffies, g=140181, q=528 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 20054 Comm: syz.2.3472 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 RIP: 0010:match_held_lock+0x82/0xb0 kernel/locking/lockdep.c:5337 Code: b6 c0 c3 cc cc cc cc 90 e8 3b 8e 60 f9 85 c0 74 0a 8b 05 d1 20 69 05 85 c0 74 24 90 31 c0 5b e9 c4 40 03 00 b8 01 00 00 00 5b cc cc cc cc 31 f6 e8 42 fe ff ff 48 85 c0 75 8a 31 c0 eb df 48 RSP: 0018:ffffc90000007da0 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffff88804d4b02c0 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffff88804d4b02c0 RDI: ffff88802d8c8c18 RBP: ffff88802d8c8000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 00000000ffffffff R13: 0000000000000046 R14: ffff88802d8c8c18 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff888123de8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2ccf45 CR3: 000000002a4f2000 CR4: 00000000003526f0 Call Trace: __lock_is_held kernel/locking/lockdep.c:5601 [inline] lock_is_held_type+0x9d/0x140 kernel/locking/lockdep.c:5940 lock_is_held include/linux/lockdep.h:249 [inline] advance_sched+0x7a4/0xd20 net/sched/sch_taprio.c:935 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:clear_pages arch/x86/include/asm/page_64.h:103 [inline] RIP: 0010:clear_highpages_kasan_tagged+0x63/0x90 mm/page_alloc.c:1221 Code: 00 00 00 fc ff df 48 c1 fb 06 48 c1 e8 03 48 c1 e3 0c 80 3c 10 00 75 2e 48 8b 3d 78 61 db 0b 89 e9 31 c0 48 c1 e1 0c 48 01 df aa 0f 1f 44 00 00 5b 5d e9 cf 56 0f 00 48 c7 c7 50 2f 46 8e e8 RSP: 0018:ffffc90005746fa8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 000000003d777000 RCX: 0000000000001000 RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff88803d777000 RBP: 0000000000000001 R08: 0000000000001000 R09: 0000000000000000 R10: ffffed1007aeee00 R11: dffffc0000000000 R12: 0000000000000001 R13: ffffea0000f5ddc0 R14: 0000000000002800 R15: 0000000000000001 post_alloc_hook+0xba/0x120 mm/page_alloc.c:1857 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304 alloc_pages_mpol+0x1fb/0x540 mm/mempolicy.c:2490 alloc_pages_noprof+0x1a/0x160 mm/mempolicy.c:2581 get_free_pages_noprof+0x10/0xb0 mm/page_alloc.c:5363 tlb_next_batch mm/mmu_gather.c:37 [inline] __tlb_remove_folio_pages_size.isra.0+0x2dc/0x550 mm/mmu_gather.c:198 zap_present_folio_ptes mm/memory.c:1677 [inline] zap_present_ptes mm/memory.c:1730 [inline] do_zap_pte_range mm/memory.c:1832 [inline] zap_pte_range mm/memory.c:1934 [inline] zap_pmd_range mm/memory.c:2020 [inline] zap_pud_range mm/memory.c:2048 [inline] zap_p4d_range mm/memory.c:2069 [inline] __zap_vma_range+0x149c/0x4a30 mm/memory.c:2109 unmap_vmas+0x299/0x5f0 mm/memory.c:2178 exit_mmap+0x1ef/0xa00 mm/mmap.c:1300 __mmput+0x12a/0x410 kernel/fork.c:1187 mmput+0x67/0x80 kernel/fork.c:1210 exit_mm kernel/exit.c:615 [inline] do_exit+0x8b1/0x2ae0 kernel/exit.c:997 do_group_exit+0xd5/0x2a0 kernel/exit.c:1152 get_signal+0x1ec7/0x21e0 kernel/signal.c:3046 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x139/0x6f0 kernel/entry/common.c:101 __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:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x666/0x870 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f339d79de59 Code: Unable to access opcode bytes at 0x7f339d79de2f. RSP: 002b:00007f339e6250e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f339da25fa8 RCX: 00007f339d79de59 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f339da25fa8 RBP: 00007f339da25fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f339da26038 R14: 00007ffe59a4d460 R15: 00007ffe59a4d548 rcu: rcu_preempt kthread starved for 10500 jiffies! g140181 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:27528 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 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: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 76 8d 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 39 12 00 fb f4 bc 48 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197e00 EFLAGS: 00000246 RAX: 0000000007d24639 RBX: ffff88801ea82540 RCX: ffffffff8bb962d5 RDX: 0000000000000000 RSI: ffffffff8e1a4091 RDI: ffffffff8c401180 RBP: ffffed1003d504a8 R08: 0000000000000001 R09: ffffed10170a678d R10: ffff8880b8533c6b R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 1ffff92000032fc4 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888123ee8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200001000000 CR3: 00000000575a0000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:768 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x158