rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P14447/1:b..l P16793/1:b..l P2/1:b..l rcu: (detected by 1, t=10503 jiffies, g=134301, q=912021 ncpus=2) task:kthreadd state:R running task stack:25976 pid:2 tgid:2 ppid:0 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7284 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7606 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x920 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:deref_stack_reg+0x183/0x220 arch/x86/kernel/unwind_orc.c:422 Code: 39 c4 0f 96 c1 4d 39 c6 0f 97 c2 20 c2 20 ca 80 fa 01 75 46 49 8d 40 08 4c 39 e0 0f 97 c1 4c 39 f0 0f 96 c0 20 c8 3c 01 75 30 <4c> 89 c7 49 89 f7 e8 12 07 00 00 49 89 c6 48 8b 5c 24 08 48 89 d8 RSP: 0018:ffffc90000077258 EFLAGS: 00000202 RAX: ffffc90000077601 RBX: 1ffff9200000ee69 RCX: 0000000000000001 RDX: ffffc90000077388 RSI: dffffc0000000000 RDI: ffffc90000077358 RBP: ffffc90000070000 R08: ffffc90000077670 R09: 0000000000000000 R10: ffffc90000077398 R11: fffff5200000ee75 R12: 1ffff9200000ee6a R13: 1ffff9200000ee6b R14: ffffc90000078000 R15: ffffc90000077348 unwind_next_frame+0x19bd/0x2550 arch/x86/kernel/unwind_orc.c:-1 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:183 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:338 reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962 __slab_free+0x274/0x2c0 mm/slub.c:5823 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:361 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_noprof+0x307/0x720 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] lsm_blob_alloc security/security.c:218 [inline] lsm_cred_alloc security/security.c:235 [inline] security_prepare_creds+0x52/0x360 security/security.c:2866 prepare_creds+0x57d/0x820 kernel/cred.c:215 copy_creds+0x109/0x9f0 kernel/cred.c:286 copy_process+0xcf9/0x4400 kernel/fork.c:2175 kernel_clone+0x2d7/0x940 kernel/fork.c:2771 kernel_thread+0x13f/0x1b0 kernel/fork.c:2832 create_kthread kernel/kthread.c:459 [inline] kthreadd+0x4ec/0x6e0 kernel/kthread.c:817 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:syz.1.2951 state:R running task stack:26856 pid:16793 tgid:16789 ppid:14447 task_flags:0x40044c flags:0x08080002 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7284 preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7463 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:201 [inline] _raw_spin_unlock+0x41/0x50 kernel/locking/spinlock.c:213 spin_unlock include/linux/spinlock.h:401 [inline] zap_pte_range mm/memory.c:2095 [inline] zap_pmd_range mm/memory.c:2151 [inline] zap_pud_range mm/memory.c:2179 [inline] zap_p4d_range mm/memory.c:2200 [inline] __zap_vma_range+0x40e1/0x4f80 mm/memory.c:2240 unmap_vmas+0x390/0x550 mm/memory.c:2309 exit_mmap+0x293/0x9f0 mm/mmap.c:1315 __mmput+0x118/0x420 kernel/fork.c:1193 exit_mm+0x18e/0x240 kernel/exit.c:592 do_exit+0x6cd/0x2360 kernel/exit.c:974 do_group_exit+0x22d/0x2f0 kernel/exit.c:1129 get_signal+0x121b/0x12c0 kernel/signal.c:3112 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x10e/0x770 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:343 [inline] __do_fast_syscall_32+0x437/0x6b0 arch/x86/entry/syscall_32.c:294 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:316 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf73ef0ec RSP: 002b:00000000f4fa150c EFLAGS: 00000206 ORIG_RAX: 0000000000000168 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000005 RDX: 0000000000000000 RSI: 0000000080000240 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 task:syz-executor state:R running task stack:21928 pid:14447 tgid:14447 ppid:14435 task_flags:0x400140 flags:0x08080000 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7284 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7606 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x920 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:118 [inline] RIP: 0010:lock_acquire+0x7d/0x350 kernel/locking/lockdep.c:5918 Code: e8 c8 36 09 00 84 c0 0f 84 e2 01 00 00 83 3d c9 3d d7 0f 00 0f 84 e9 00 00 00 48 8b b4 24 88 00 00 00 4c 89 e7 e8 13 5f 95 00 <83> 3d ac 3d d7 0f 00 0f 84 e4 00 00 00 65 8b 05 d7 ed f2 12 85 c0 RSP: 0018:ffffc900037bf068 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 8000000000000001 RDX: 0000000000000000 RSI: ffffffff817811fc RDI: 1ffffffff1fab914 RBP: 1ffff920006f7e3c R08: 0000000000000000 R09: 0000000000000000 R10: ffffc900037bf1f8 R11: ffffffff81b2c570 R12: ffffffff8fd5c8a0 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] class_rcu_constructor include/linux/rcupdate.h:1216 [inline] unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:183 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:338 reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962 __slab_free+0x274/0x2c0 mm/slub.c:5823 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:361 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] __do_kmalloc_node mm/slub.c:5413 [inline] __kmalloc_noprof+0x307/0x720 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] tomoyo_encode2 security/tomoyo/realpath.c:45 [inline] tomoyo_encode+0x2ad/0x570 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x5fa/0x640 security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x229/0x470 security/tomoyo/file.c:776 security_file_open+0xa9/0x240 security/security.c:2739 do_dentry_open+0x4a0/0x1380 fs/open.c:973 vfs_open+0x3b/0x340 fs/open.c:1101 do_open fs/namei.c:4866 [inline] path_openat+0x1443/0x1d60 fs/namei.c:5029 do_file_open+0x23e/0x4a0 fs/namei.c:5058 do_sys_openat2+0x115/0x200 fs/open.c:1417 do_sys_open fs/open.c:1423 [inline] __do_compat_sys_openat fs/open.c:1485 [inline] __se_compat_sys_openat fs/open.c:1483 [inline] __ia32_compat_sys_openat+0x131/0x160 fs/open.c:1483 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline] __do_fast_syscall_32+0x27a/0x6b0 arch/x86/entry/syscall_32.c:291 do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:316 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf73ef0ec RSP: 002b:00000000f753fd50 EFLAGS: 00000206 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 00000000f721234c RDX: 0000000000098800 RSI: 0000000000000000 RDI: 00000000f73daff4 RBP: 0000000000000129 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 8138 jiffies! g134301 f0x2 RCU_GP_WAIT_FQS(5) ->state=R ->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:27752 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5533 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7284 __schedule_loop kernel/sched/core.c:7361 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7376 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330 kthread+0x38b/0x480 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: 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 10/07/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 1b 8b 02 e9 c3 08 03 00 cc cc cc 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 e3 d5 20 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffc900001a7e40 EFLAGS: 00000246 RAX: 00000000017b4747 RBX: ffffffff819beb9c RCX: 8000000000000001 RDX: 0000000000000001 RSI: ffffffff8e469aca RDI: ffffffff8c6dde80 RBP: ffffc900001a7f10 R08: ffff8880b8533a1b R09: 1ffff110170a6743 R10: dffffc0000000000 R11: ffffed10170a6744 R12: 0000000000000000 R13: 1ffff11003ed1bb8 R14: 1ffff92000034fd0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888123bbf000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000005843723c CR3: 0000000034412000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/kernel/process.c:767 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:768 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x1cc/0x540 kernel/sched/idle.c:355 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x157