rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10159/1:b..l P4274/1:b..l (detected by 1, t=10503 jiffies, g=70009, q=57 ncpus=2) task:syz-executor state:R running task stack:21136 pid:4274 ppid:4272 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline] RIP: 0010:lock_is_held_type+0x61/0x190 kernel/locking/lockdep.c:5701 Code: 0f 85 f4 00 00 00 65 48 8b 1d 3b 16 d3 75 83 bb dc 0a 00 00 00 0f 85 df 00 00 00 41 89 f7 49 89 fe 48 c7 04 24 00 00 00 00 9c <8f> 04 24 4c 8b 2c 24 fa 48 c7 c7 80 27 8c 8a e8 eb 12 00 00 65 ff RSP: 0018:ffffc90003d27298 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff88801929bc00 RCX: ffd84cb084c37300 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff8cb2de60 RBP: 00000000ffffffff R08: dffffc0000000000 R09: 1ffffffff215fe48 R10: dffffc0000000000 R11: fffffbfff215fe49 R12: ffff88801929d238 R13: dffffc0000000000 R14: ffffffff8cb2de60 R15: 00000000ffffffff task_css include/linux/cgroup.h:509 [inline] mem_cgroup_from_task+0x96/0x110 mm/memcontrol.c:985 get_obj_cgroup_from_current mm/memcontrol.c:3023 [inline] __memcg_kmem_charge_page+0x185/0x380 mm/memcontrol.c:3123 __alloc_pages+0x222/0x4f0 mm/page_alloc.c:5674 __pte_alloc_one include/asm-generic/pgalloc.h:63 [inline] pte_alloc_one+0x7b/0x310 arch/x86/mm/pgtable.c:33 __pte_alloc+0x21/0x150 mm/memory.c:468 copy_pte_range mm/memory.c:1042 [inline] copy_pmd_range mm/memory.c:1177 [inline] copy_pud_range mm/memory.c:1214 [inline] copy_p4d_range mm/memory.c:1238 [inline] copy_page_range+0x3118/0x3900 mm/memory.c:1332 dup_mmap kernel/fork.c:703 [inline] dup_mm kernel/fork.c:1547 [inline] copy_mm+0xec3/0x1690 kernel/fork.c:1596 copy_process+0x1979/0x4080 kernel/fork.c:2357 kernel_clone+0x24b/0x900 kernel/fork.c:2764 __do_sys_clone kernel/fork.c:2905 [inline] __se_sys_clone kernel/fork.c:2889 [inline] __x64_sys_clone+0x1a7/0x220 kernel/fork.c:2889 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fdc86dc58d2 RSP: 002b:00007ffd174623e0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffd174623e0 RCX: 00007fdc86dc58d2 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffd1746256c R08: 0000000000000000 R09: 0000000000000001 R10: 0000555592d177d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 00000000000b730e R15: 00007ffd174625c0 task:syz.8.1220 state:R running task stack:26576 pid:10159 ppid:5633 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 RIP: 0010:unwind_done arch/x86/include/asm/unwind.h:50 [inline] RIP: 0010:unwind_next_frame+0x7f/0x20b0 arch/x86/kernel/unwind_orc.c:429 Code: 00 74 08 4c 89 ff e8 c0 68 9a 00 4c 89 7c 24 58 4c 8b 6b 38 49 89 df 49 c1 ef 03 43 0f b6 04 37 84 c0 0f 85 a0 19 00 00 8b 03 <85> c0 0f 84 79 18 00 00 48 89 6c 24 08 89 84 24 8c 00 00 00 4c 89 RSP: 0018:ffffc90004937790 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffffc90004937868 RCX: 0000000080000000 RDX: dffffc0000000000 RSI: ffffffff8a4000cc RDI: ffffc90004937868 RBP: ffffc900049378b0 R08: ffffc90004937930 R09: 000000000000000c R10: dffffc0000000000 R11: fffff52000926f19 R12: ffffffff8a4000cc R13: ffffc90004937f58 R14: dffffc0000000000 R15: 1ffff92000926f0d arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122 save_stack+0x121/0x230 mm/page_owner.c:127 __reset_page_owner+0x51/0x1a0 mm/page_owner.c:148 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1486 [inline] free_pcp_prepare mm/page_alloc.c:1536 [inline] free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3413 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3508 __vunmap+0x856/0xa00 mm/vmalloc.c:2726 do_free_pages sound/core/pcm_memory.c:93 [inline] snd_pcm_lib_free_pages+0x1e4/0x2a0 sound/core/pcm_memory.c:499 do_hw_free sound/core/pcm_native.c:893 [inline] snd_pcm_release_substream+0x29e/0x460 sound/core/pcm_native.c:2739 snd_pcm_oss_release_file sound/core/oss/pcm_oss.c:2414 [inline] snd_pcm_oss_release+0x180/0x240 sound/core/oss/pcm_oss.c:2593 __fput+0x22c/0x920 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f084db9ce59 RSP: 002b:00007f084ea22028 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f084de15fa0 RCX: 00007f084db9ce59 RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000003 RBP: 00007f084dc32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f084de16038 R14: 00007f084de15fa0 R15: 00007fff95b99728 rcu: rcu_preempt kthread starved for 10586 jiffies! g70009 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:26992 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6731 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6755 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x10d/0x120 kernel/locking/spinlock.c:194 rcu_gp_fqs_loop+0x31c/0x1340 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:742 Code: 48 89 df e8 37 34 9a f7 e9 44 ff ff ff e8 cd 06 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d a7 5a 4d 00 fb f4 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48 RSP: 0018:ffffc90000177de8 EFLAGS: 000002c6 RAX: 897431ecbcbfae00 RBX: ffffffff8a395407 RCX: 897431ecbcbfae00 RDX: 0000000000000001 RSI: ffffffff8a8c1aa0 RDI: ffffffff8adf2060 RBP: ffffc90000177f20 R08: ffff8880b8f3580b R09: 1ffff110171e6b01 R10: dffffc0000000000 R11: ffffed10171e6b02 R12: 0000000000000000 R13: dffffc0000000000 R14: ffff888017739e00 R15: 1ffff9200002efc8 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f840c1ea540 CR3: 0000000065fe9000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: default_idle_call+0x84/0xc0 kernel/sched/idle.c:109 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x250/0x680 kernel/sched/idle.c:323 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:422 start_secondary+0xe4/0xf0 arch/x86/kernel/smpboot.c:281 secondary_startup_64_no_verify+0xcf/0xdb vkms_vblank_simulate: vblank timer overrun