rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13386/1:b..l rcu: (detected by 1, t=10506 jiffies, g=69845, q=299 ncpus=2) task:syz.3.2071 state:R running task stack:26696 pid:13386 tgid:13379 ppid:5618 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa00 kernel/entry/common.c:167 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:679 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x70 kernel/kcov.c:217 Code: 48 89 df 5b e9 1d 6c 64 00 be 03 00 00 00 5b e9 c2 c4 13 03 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <65> 8b 05 45 fe 59 12 48 8b 34 24 65 48 8b 15 21 fe 59 12 a9 00 01 RSP: 0018:ffffc9000520f4b8 EFLAGS: 00000202 RAX: 0000000000000002 RBX: 0000000000000001 RCX: ffffffff82a237fb RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff888052728000 RBP: ffffc9000520f5d0 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000 R13: 0000000000000feb R14: 0000000000000001 R15: ffff88802bdb2feb rcu_read_unlock include/linux/rcupdate.h:869 [inline] prepend_path+0xd85/0x1060 fs/d_path.c:182 d_absolute_path+0xfb/0x1b0 fs/d_path.c:234 tomoyo_get_absolute_path security/tomoyo/realpath.c:101 [inline] tomoyo_realpath_from_path+0x358/0x690 security/tomoyo/realpath.c:271 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_number_perm+0x23c/0x580 security/tomoyo/file.c:728 tomoyo_path_mknod+0x164/0x190 security/tomoyo/tomoyo.c:252 security_path_mknod+0x161/0x300 security/security.c:1417 may_o_create+0x30/0x3a0 fs/namei.c:4324 lookup_open fs/namei.c:4464 [inline] open_last_lookups fs/namei.c:4608 [inline] path_openat+0x2e42/0x4280 fs/namei.c:4860 do_file_open+0x20e/0x430 fs/namei.c:4892 do_sys_openat2+0x10f/0x1e0 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_openat fs/open.c:1390 [inline] __se_sys_openat fs/open.c:1385 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1385 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2b0279e019 RSP: 002b:00007f2b03699028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f2b02a26090 RCX: 00007f2b0279e019 RDX: 0000000000143142 RSI: 0000200000000400 RDI: ffffffffffffff9c RBP: 00007f2b0283500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000120 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2b02a26128 R14: 00007f2b02a26090 R15: 00007ffc0ffca318 rcu: rcu_preempt kthread starved for 10506 jiffies! g69845 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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:27592 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 13395 Comm: syz.1.2073 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline] RIP: 0010:mark_lock+0x52/0xa20 kernel/locking/lockdep.c:4731 Code: 89 d3 83 fa 08 74 6d 41 be 01 00 00 00 89 d9 41 d3 e6 4d 63 f6 41 0f b7 44 24 20 66 25 ff 1f 0f b7 c0 48 0f a3 05 8e 5d 85 14 <73> 5b 48 8d 04 80 48 8d 04 80 48 8d 04 c5 e0 2d 6b 96 4c 89 f1 48 RSP: 0018:ffffc90000007bb0 EFLAGS: 00000047 RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000008 RDX: 0000000000000008 RSI: ffff88807e61b108 RDI: ffff88807e61a540 RBP: ffffc90000007c48 R08: 0000000000000001 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88807e61b108 R13: ffff88807e61a540 R14: 0000000000000100 R15: 0000000000000001 FS: 00007f389dbd56c0(0000) GS:ffff888123dda000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f587796e420 CR3: 000000007ca53000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 000000000000000b DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: mark_usage kernel/locking/lockdep.c:4674 [inline] __lock_acquire+0x49f/0x1a40 kernel/locking/lockdep.c:5191 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166 debug_object_deactivate+0x135/0x3b0 lib/debugobjects.c:936 debug_hrtimer_deactivate kernel/time/hrtimer.c:490 [inline] __run_hrtimer kernel/time/hrtimer.c:2000 [inline] __hrtimer_run_queues+0x2e9/0x9c0 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:its_return_thunk+0x0/0x10 arch/x86/lib/retpoline.S:417 Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 e9 8b a7 b6 f5 cc RSP: 0018:ffffc900025779b0 EFLAGS: 00000292 RAX: 0000000000000000 RBX: 1ffff920004aef37 RCX: 0000000000000001 RDX: 0000000000000046 RSI: ffffffff8e181841 RDI: ffffffff8c402680 RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff8c3e25a0 R13: 00000000000000a9 R14: 0000200000029d40 R15: dffffc0000000000 lock_is_held include/linux/lockdep.h:249 [inline] __might_resched+0x248/0x330 kernel/sched/core.c:9159 __might_fault+0x8b/0x140 mm/memory.c:7290 _inline_copy_from_user include/linux/uaccess.h:169 [inline] _copy_from_user+0x29/0xd0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:222 [inline] copy_msghdr_from_user+0x9f/0x4c0 net/socket.c:2614 recvmsg_copy_msghdr net/socket.c:2870 [inline] ___sys_recvmsg+0xdd/0x1a0 net/socket.c:2942 do_recvmmsg+0x2f3/0x740 net/socket.c:3041 __sys_recvmmsg net/socket.c:3115 [inline] __do_sys_recvmmsg net/socket.c:3138 [inline] __se_sys_recvmmsg net/socket.c:3131 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3131 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f389f99e019 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:00007f389dbd5028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f389fc26090 RCX: 00007f389f99e019 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004 RBP: 00007f389fa3500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f389fc26128 R14: 00007f389fc26090 R15: 00007fffe8952cc8