rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-....: (0 ticks this GP) idle=831/1/0x4000000000000002 softirq=29553/29553 fqs=5228 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11267 (detected by 1, t=10502 jiffies, g=38221, q=748) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 11267 Comm: syz.8.1789 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:202 Code: 66 2e 0f 1f 84 00 00 00 00 00 53 48 89 fb e8 17 00 00 00 48 8b 3d d0 6b f1 0b 48 89 de 5b e9 d7 9e 43 00 00 00 cc cc 00 00 cc <48> 8b 04 24 65 48 8b 0d a4 a3 8a 7e 65 8b 15 a5 a3 8a 7e 81 e2 00 RSP: 0018:ffffc90000007260 EFLAGS: 00000097 RAX: ffffffff818392d0 RBX: ffff8880b903b1f0 RCX: ffff88807b0e3b80 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 0000000000000000 R08: dffffc0000000000 R09: ffff8880b903b1f0 R10: ffffed1017207640 R11: 1ffff1101720763e R12: ffff8880b903b208 R13: dffffc0000000000 R14: ffff8880b903b200 R15: 1ffff11017207641 FS: 00007f9f7930c6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c312426 CR3: 0000000045341000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: cpu_max_bits_warn include/linux/cpumask.h:108 [inline] cpumask_check include/linux/cpumask.h:115 [inline] cpumask_test_cpu include/linux/cpumask.h:344 [inline] cpu_online include/linux/cpumask.h:895 [inline] irq_work_queue_on+0x2e/0x220 kernel/irq_work.c:95 rcu_read_unlock_special+0x379/0x480 kernel/rcu/tree_plugin.h:667 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] __perf_event_output kernel/events/core.c:7813 [inline] perf_event_output_forward+0x216/0x280 kernel/events/core.c:7822 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515 perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021 perf_trace_preemptirq_template+0x2be/0x380 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194 Code: 74 05 e8 be 9a d2 f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 d6 22 a6 f7 65 8b 05 67 20 57 76 85 c0 74 3c 48 c7 04 24 0e 36 RSP: 0018:ffffc90000007a00 EFLAGS: 00000206 RAX: a01d8e2a9d646000 RBX: 0000000000000a02 RCX: a01d8e2a9d646000 RDX: dffffc0000000000 RSI: ffffffff8a0b1be0 RDI: 0000000000000001 RBP: ffffc90000007a88 R08: dffffc0000000000 R09: fffffbfff1ff5433 R10: fffffbfff1ff5433 R11: 1ffffffff1ff5432 R12: dffffc0000000000 R13: ffff88802bf8b640 R14: ffffffff962d6308 R15: 1ffff92000000f40 __debug_check_no_obj_freed lib/debugobjects.c:982 [inline] debug_check_no_obj_freed+0x515/0x530 lib/debugobjects.c:1003 slab_free_hook mm/slub.c:1685 [inline] slab_free_freelist_hook+0x8b/0x170 mm/slub.c:1736 slab_free mm/slub.c:3504 [inline] kmem_cache_free+0x8f/0x210 mm/slub.c:3520 rcu_do_batch kernel/rcu/tree.c:2523 [inline] rcu_core+0x962/0x15d0 kernel/rcu/tree.c:2763 handle_softirqs+0x328/0x820 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ed 11 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc900014df4e0 EFLAGS: 00000206 RAX: a01d8e2a9d646000 RBX: 1ffff9200029bea0 RCX: a01d8e2a9d646000 RDX: dffffc0000000000 RSI: ffffffff8a0b1be0 RDI: ffffffff8a59e800 RBP: ffffc900014df5b8 R08: dffffc0000000000 R09: fffffbfff1ff5433 R10: fffffbfff1ff5433 R11: 1ffffffff1ff5432 R12: ffffffff8c120c01 R13: dffffc0000000000 R14: 0000000000000246 R15: ffff88807b0e3b80 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:772 [inline] d_alloc_parallel+0x107b/0x1330 fs/dcache.c:2673 __lookup_slow+0x113/0x3d0 fs/namei.c:1656 lookup_slow+0x53/0x70 fs/namei.c:1688 walk_component+0x319/0x460 fs/namei.c:1984 lookup_last fs/namei.c:2439 [inline] path_lookupat+0x169/0x440 fs/namei.c:2463 do_o_path+0x94/0x1f0 fs/namei.c:3721 path_openat+0x2954/0x2f30 fs/namei.c:3743 do_filp_open+0x1b3/0x3e0 fs/namei.c:3777 do_sys_openat2+0x142/0x4a0 fs/open.c:1255 do_sys_open fs/open.c:1271 [inline] __do_sys_openat fs/open.c:1287 [inline] __se_sys_openat fs/open.c:1282 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1282 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f9f7b0a5749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9f7930c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f9f7b2fbfa0 RCX: 00007f9f7b0a5749 RDX: 0000000000200002 RSI: 0000200000000180 RDI: 0000000000000004 RBP: 00007f9f7b129f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9f7b2fc038 R14: 00007f9f7b2fbfa0 R15: 00007ffd0d279838 task:syz.8.1789 state:R running task stack:24864 pid:11267 ppid: 8515 flags:0x0000400c Call Trace: