rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5193/1:b..l P13756/4:b..l rcu: (detected by 0, t=10502 jiffies, g=60653, q=98 ncpus=2) task:syz-executor state:R running task stack:28280 pid:13756 tgid:13756 ppid:12910 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x169e/0x54f0 kernel/sched/core.c:7188 preempt_schedule_notrace+0x57/0x90 kernel/sched/core.c:7462 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_lockdep_current_cpu_online+0x107/0x120 kernel/rcu/tree.c:4050 rcu_read_lock_held_common kernel/rcu/update.c:113 [inline] rcu_read_lock_held+0x1e/0x50 kernel/rcu/update.c:349 xa_entry include/linux/xarray.h:1226 [inline] xas_next_entry+0x202/0x3d0 include/linux/xarray.h:1731 next_uptodate_folio+0x29/0x6b0 mm/filemap.c:3704 filemap_map_pages+0x125b/0x1d10 mm/filemap.c:3939 do_fault_around mm/memory.c:5851 [inline] do_read_fault mm/memory.c:5884 [inline] do_fault mm/memory.c:6027 [inline] do_pte_missing+0x1646/0x2950 mm/memory.c:4550 handle_pte_fault mm/memory.c:6411 [inline] __handle_mm_fault mm/memory.c:6549 [inline] handle_mm_fault+0xdb5/0x14c0 mm/memory.c:6718 do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f5879b1a9e8 RSP: 002b:00007ffcbda707a0 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 0000000000000030 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 00007ffcbda707dc R08: 00007f587a9f8060 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000017 R13: 00000000000927c0 R14: 00000000000c3775 R15: 00007ffcbda70830 task:udevd state:R running task stack:25368 pid:5193 tgid:5193 ppid:1 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x169e/0x54f0 kernel/sched/core.c:7188 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7512 irqentry_exit_to_kernel_mode_preempt+0x14/0x70 include/linux/irq-entry-common.h:476 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x14f/0x680 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5874 Code: ff ff ff e8 71 be 94 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 4b 79 d5 10 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 98 cb ef RSP: 0018:ffffc900038ef018 EFLAGS: 00000286 RAX: 9eabdfeb6fa18d00 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000f961ca2a RSI: ffffffff8d8aeeca RDI: ffffffff8ba83760 RBP: ffffffff81770226 R08: ffffffff81770226 R09: ffffffff8dfc80c0 R10: ffffc900038ef178 R11: ffffffff81afc300 R12: 0000000000000002 R13: ffffffff8dfc80c0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0xc3/0x2550 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 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2689 [inline] slab_free mm/slub.c:6246 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6561 tomoyo_realpath_from_path+0x598/0x5d0 security/tomoyo/realpath.c:286 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+0x4c0/0x13e0 fs/open.c:924 vfs_open+0x3b/0x350 fs/open.c:1079 do_open fs/namei.c:4699 [inline] path_openat+0x2e43/0x38a0 fs/namei.c:4858 do_file_open+0x23e/0x4a0 fs/namei.c:4887 do_sys_openat2+0x113/0x200 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1381 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f78a13b0c3a RSP: 002b:00007ffe0bba7598 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000055f2b997bf10 RCX: 00007f78a13b0c3a RDX: 0000000000090800 RSI: 000055f2b996ab50 RDI: 00000000ffffff9c RBP: 000055f2b996ab50 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 000055f2b99677b0 R13: 00000000000000ff R14: 000055f29b6e8be0 R15: 00007ffe0bba7830 rcu: rcu_preempt kthread starved for 10496 jiffies! g60653 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:24104 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x169e/0x54f0 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+0x312/0x11b0 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 13752 Comm: syz.8.554 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:preempt_latency_start kernel/sched/core.c:5838 [inline] RIP: 0010:preempt_count_add+0x9e/0x190 kernel/sched/core.c:5861 Code: 65 8b 05 05 30 e2 10 25 ff ff ff 7f 39 f8 75 42 48 8b 5c 24 18 48 89 df e8 1f 41 0d 00 85 c0 74 09 31 db 31 ff e8 12 41 0d 00 <65> 4c 8b 35 b2 2f e2 10 49 81 c6 d0 15 00 00 4c 89 f0 48 c1 e8 03 RSP: 0018:ffffc9000474fc60 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff81c50e62 RCX: ffffffff99813300 RDX: 0000000000000002 RSI: 0000000000000000 RDI: ffffffff81c50e62 RBP: ffffc9000474fee0 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffed100704e506 R12: 0000000000000000 R13: ffff888038272800 R14: dffffc0000000000 R15: dffffc0000000000 FS: 00007f52e9a566c0(0000) GS:ffff8881261c2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f587a9fda08 CR3: 000000003f830000 CR4: 00000000003526f0 Call Trace: class_preempt_constructor include/linux/preempt.h:468 [inline] __migrate_disable include/linux/sched.h:2480 [inline] migrate_disable include/linux/sched.h:2498 [inline] bpf_prog_run_pin_on_cpu include/linux/filter.h:745 [inline] seccomp_run_filters kernel/seccomp.c:424 [inline] __seccomp_filter+0x4d2/0x1ef0 kernel/seccomp.c:1274 syscall_trace_enter include/linux/entry-common.h:113 [inline] syscall_enter_from_user_mode_work include/linux/entry-common.h:157 [inline] syscall_enter_from_user_mode include/linux/entry-common.h:188 [inline] do_syscall_64+0xf9/0xf80 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f52eb7fc819 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:00007f52e9a560e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f52eba75fa8 RCX: 00007f52eb7fc819 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f52eba75fa8 RBP: 00007f52eba75fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f52eba76038 R14: 00007fff6e80deb0 R15: 00007fff6e80df98