rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=6724/1/0x4000000000000000 softirq=46931/46932 fqs=53 rcu: (detected by 1, t=10502 jiffies, g=47985, q=479 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 12560 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:__lock_is_held kernel/locking/lockdep.c:5601 [inline] RIP: 0010:lock_is_held_type+0x84/0x150 kernel/locking/lockdep.c:5940 Code: 65 ff 05 ff dd 90 07 41 83 bd 88 0b 00 00 00 7e 48 4c 89 eb 48 81 c3 90 0b 00 00 45 31 ff 49 83 ff 31 73 24 48 89 df 4c 89 f6 f7 01 00 00 85 c0 75 2a 49 ff c7 49 63 85 88 0b 00 00 48 83 c3 RSP: 0018:ffffc90000007cd8 EFLAGS: 00000087 RAX: 0000000000000005 RBX: ffff88807c244960 RCX: 0000000000010002 RDX: ffff88807c243d80 RSI: ffff8880796312c0 RDI: ffff88807c244960 RBP: 00000000ffffffff R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000f90 R12: 0000000000000046 R13: ffff88807c243d80 R14: ffff8880796312c0 R15: 0000000000000002 FS: 00005555706b1500(0000) GS:ffff88812528a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcab43adac0 CR3: 0000000074d14000 CR4: 00000000003526f0 Call Trace: lock_is_held include/linux/lockdep.h:249 [inline] advance_sched+0x14c/0xc20 net/sched/sch_taprio.c:933 __run_hrtimer kernel/time/hrtimer.c:1930 [inline] __hrtimer_run_queues+0x3c0/0xa20 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:alloc_from_pcs mm/slub.c:4748 [inline] RIP: 0010:slab_alloc_node mm/slub.c:4883 [inline] RIP: 0010:__do_kmalloc_node mm/slub.c:5294 [inline] RIP: 0010:__kmalloc_noprof+0x22c/0x760 mm/slub.c:5307 Code: 20 4d 8b 2c 24 e8 34 57 83 09 41 89 c7 83 f8 08 0f 83 a6 03 00 00 4a 8b 04 fd 90 67 26 8e 4a 8d 2c 28 4a 8b 44 28 38 8b 48 18 <85> c9 0f 84 33 02 00 00 8b 54 24 04 ff c9 48 8b 7c c8 20 84 d2 0f RSP: 0018:ffffc9000252f9f8 EFLAGS: 00000293 RAX: ffff888078fd2400 RBX: 0000000000000d40 RCX: 0000000000000018 RDX: 000000005522062f RSI: ffffffff8c28af40 RDI: ffffffff8c28af00 RBP: ffff8880b863f4f8 R08: ffffffff822588e8 R09: ffff8880b863f4f8 R10: 0000000000000009 R11: 0000000000000000 R12: ffff88813fe1a8c0 R13: ffffffff933b54f8 R14: 0000000000000022 R15: 0000000000000000 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] tomoyo_encode2 security/tomoyo/realpath.c:45 [inline] tomoyo_encode+0x28b/0x550 security/tomoyo/realpath.c:80 tomoyo_path_perm+0x318/0x560 security/tomoyo/file.c:836 tomoyo_path_symlink+0xab/0xf0 security/tomoyo/tomoyo.c:212 security_path_symlink+0x16f/0x360 security/security.c:1502 filename_symlinkat+0x134/0x410 fs/namei.c:5666 __do_sys_symlinkat fs/namei.c:5688 [inline] __se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5683 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: 0033:0x7fcab439bf17 Code: 44 00 00 48 89 f2 31 c9 48 89 fe bf 9c ff ff ff e9 8e f5 ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 b8 0a 01 00 00 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:00007ffd51d246a8 EFLAGS: 00000202 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcab439bf17 RDX: 00007fcab4433d28 RSI: 00000000ffffff9c RDI: 00007ffd51d24740 RBP: 00007ffd51d246ec R08: 0000000000000001 R09: 00000000ffffffff R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000015d R13: 00000000000927c0 R14: 000000000004c5dc R15: 00007ffd51d24740 rcu: rcu_preempt kthread starved for 10389 jiffies! g47985 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:27544 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x389/0x470 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: CPU: 1 UID: 0 PID: 5625 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xfcf/0x13d0 kernel/smp.c:892 Code: 79 45 8b 2e 44 89 ee 83 e6 01 31 ff e8 7a 06 0c 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 25 02 0c 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 0a 02 0c RSP: 0000:ffffc90003f07840 EFLAGS: 00000293 RAX: ffffffff81b9c256 RBX: ffff8880b873c148 RCX: ffff88802abf9ec0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003f07970 R08: ffffffff9030bcf7 R09: 1ffffffff206179e R10: dffffc0000000000 R11: fffffbfff206179f R12: 1ffff110170c8589 R13: dffffc0000000000 R14: ffff8880b8642c48 R15: 0000000000000000 FS: 000055556eae8500(0000) GS:ffff88812538a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055556eb03a38 CR3: 00000000729ec000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x5c3/0x10b0 arch/x86/mm/tlb.c:1451 flush_tlb_page arch/x86/include/asm/tlbflush.h:345 [inline] ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:104 wp_page_copy mm/memory.c:3925 [inline] do_wp_page+0x3da7/0x4cc0 mm/memory.c:4320 handle_pte_fault mm/memory.c:6427 [inline] __handle_mm_fault mm/memory.c:6549 [inline] handle_mm_fault+0x151f/0x3170 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: 0033:0x7f4ccb7619e0 Code: c4 28 00 48 8d 0c 1e 49 39 d0 49 89 48 60 0f 95 c2 48 29 d8 0f b6 d2 48 83 c8 01 48 c1 e2 02 48 09 da 48 83 ca 01 48 89 56 08 <48> 89 41 08 48 8d 4e 10 eb b0 48 8d 0d a7 d9 0c 00 ba 9e 10 00 00 RSP: 002b:00007ffd7e3e7070 EFLAGS: 00010206 RAX: 00000000000065d1 RBX: 0000000000008040 RCX: 000055556eb03a30 RDX: 0000000000008041 RSI: 000055556eafb9f0 RDI: 0000000000000004 RBP: 0000000000000802 R08: 00007f4ccb9ede20 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000008030 R13: 0000000000000000 R14: 00007f4ccb9ede80 R15: 0000000000000000