rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=a334/1/0x4000000000000000 softirq=89648/89650 fqs=6 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P17666/1:b..l rcu: (detected by 1, t=10502 jiffies, g=81829, q=802 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 17710 Comm: syz.4.4283 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline] RIP: 0010:lock_release+0x4b/0x3e0 kernel/locking/lockdep.c:5879 Code: 89 44 24 28 0f 1f 44 00 00 65 8b 05 63 e4 02 11 83 f8 08 0f 83 9a 02 00 00 89 c0 48 0f a3 05 4c 1e 06 0e 73 16 e8 45 f1 08 00 <84> c0 75 0d f6 05 2e 04 f0 0d 01 0f 84 ad 02 00 00 83 3d 5d 4f 06 RSP: 0018:ffffc90000007c08 EFLAGS: 00000012 RAX: 0000000000000001 RBX: ffffffff899ab628 RCX: 0a6a14747301a600 RDX: 0000000000010000 RSI: ffffffff8be33660 RDI: ffffffff8be33620 RBP: 0000000000000001 R08: ffff88807dd1b15f R09: 1ffff1100fba362b R10: dffffc0000000000 R11: ffffed100fba362c R12: ffff88807dd1b360 R13: ffffffff899ab628 R14: ffffffff8e139ee0 R15: ffff888057871800 FS: 0000000000000000(0000) GS:ffff888125c1b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000003200 CR3: 00000000448bf000 CR4: 0000000000350ef0 Call Trace: rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] advance_sched+0xb23/0xc90 net/sched/sch_taprio.c:992 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 3b f4 02 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90003e5f4b8 EFLAGS: 00000206 RAX: 0a6a14747301a600 RBX: 0000000000000000 RCX: 0a6a14747301a600 RDX: 0000000000000000 RSI: ffffffff8dba6cac RDI: ffffffff8be33680 RBP: ffffffff822e5f1a R08: 0000000000000000 R09: ffffffff822e5f1a R10: dffffc0000000000 R11: fffff94000338a89 R12: 0000000000000002 R13: ffffffff8e139fa0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock_sched include/linux/rcupdate.h:932 [inline] pfn_valid+0xd6/0x490 include/linux/mmzone.h:2162 page_table_check_clear+0x21/0x700 mm/page_table_check.c:70 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline] get_and_clear_full_ptes include/linux/pgtable.h:725 [inline] zap_present_folio_ptes mm/memory.c:1499 [inline] zap_present_ptes mm/memory.c:1581 [inline] do_zap_pte_range mm/memory.c:1682 [inline] zap_pte_range mm/memory.c:1726 [inline] zap_pmd_range mm/memory.c:1818 [inline] zap_pud_range mm/memory.c:1847 [inline] zap_p4d_range mm/memory.c:1868 [inline] unmap_page_range+0x3445/0x4370 mm/memory.c:1889 unmap_single_vma mm/memory.c:1932 [inline] unmap_vmas+0x399/0x580 mm/memory.c:1976 exit_mmap+0x248/0xb50 mm/mmap.c:1280 __mmput+0x118/0x420 kernel/fork.c:1130 exit_mm+0x1da/0x2c0 kernel/exit.c:582 do_exit+0x648/0x2300 kernel/exit.c:949 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 __do_sys_exit_group kernel/exit.c:1113 [inline] __se_sys_exit_group kernel/exit.c:1111 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1111 x64_sys_call+0x21f7/0x2200 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f585918ebe9 Code: Unable to access opcode bytes at 0x7f585918ebbf. RSP: 002b:00007ffe651080d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f585918ebe9 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffe6510813c R08: 00000004651081cf R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 000000000000032b R13: 00000000000927c0 R14: 000000000008a86d R15: 00007ffe65108190 task:syz.0.4266 state:R running task stack:24712 pid:17666 tgid:17665 ppid:10882 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 preempt_schedule_notrace+0xd1/0x110 kernel/sched/core.c:7238 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:752 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x4b/0x3e0 kernel/locking/lockdep.c:5879 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:330 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4236 f2fs_kmem_cache_alloc_nofail fs/f2fs/f2fs.h:2951 [inline] f2fs_kmem_cache_alloc fs/f2fs/f2fs.h:2961 [inline] add_free_nid+0xd9/0x860 fs/f2fs/node.c:2353 scan_nat_page fs/f2fs/node.c:2454 [inline] __f2fs_build_free_nids fs/f2fs/node.c:2560 [inline] f2fs_build_free_nids+0xc5f/0x11c0 fs/f2fs/node.c:2606 f2fs_fill_super+0x4462/0x6ff0 fs/f2fs/super.c:5001 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1692 vfs_get_tree+0x92/0x2b0 fs/super.c:1815 do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808 do_mount fs/namespace.c:4136 [inline] __do_sys_mount fs/namespace.c:4347 [inline] __se_sys_mount+0x317/0x410 fs/namespace.c:4324 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5c4499038a RSP: 002b:00007f5c457e1e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f5c457e1ef0 RCX: 00007f5c4499038a RDX: 0000200000000040 RSI: 0000200000000200 RDI: 00007f5c457e1eb0 RBP: 0000200000000040 R08: 00007f5c457e1ef0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000200 R13: 00007f5c457e1eb0 R14: 0000000000005504 R15: 00002000000000c0 rcu: rcu_preempt kthread starved for 10490 jiffies! g81829 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:26792 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 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: 17720 Comm: syz.7.4284 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd38/0x12d0 kernel/smp.c:877 Code: 89 ee 83 e6 01 31 ff e8 06 63 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 b1 5e 0b 00 eb 38 f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 95 5e 0b 00 eb e4 44 RSP: 0018:ffffc9000540f5a0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 1ffff110170c8341 RCX: 0000000000080000 RDX: ffffc90004e23000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc9000540f720 R08: ffffffff8fa38a37 R09: 1ffffffff1f47146 R10: dffffc0000000000 R11: fffffbfff1f47147 R12: ffff8880b8641a08 R13: dffffc0000000000 R14: ffff8880b873b1c0 R15: 0000000000000000 FS: 00007f14f73f66c0(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33721ff8 CR3: 0000000029a22000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2653 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2863 __static_call_transform+0x4eb/0x750 arch/x86/kernel/static_call.c:111 arch_static_call_transform+0x98/0xc0 arch/x86/kernel/static_call.c:-1 __static_call_update+0xe4/0x5d0 kernel/static_call_inline.c:147 tracepoint_update_call kernel/tracepoint.c:271 [inline] tracepoint_add_func+0x91e/0xa10 kernel/tracepoint.c:312 tracepoint_probe_register_prio_may_exist+0x5f/0xa0 kernel/tracepoint.c:435 bpf_raw_tp_link_attach+0x4f0/0x6c0 kernel/bpf/syscall.c:4152 bpf_raw_tracepoint_open+0x1b2/0x220 kernel/bpf/syscall.c:4183 __sys_bpf+0x75a/0x870 kernel/bpf/syscall.c:6071 __do_sys_bpf kernel/bpf/syscall.c:6139 [inline] __se_sys_bpf kernel/bpf/syscall.c:6137 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6137 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f14f918ebe9 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:00007f14f73f6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f14f93b5fa0 RCX: 00007f14f918ebe9 RDX: 0000000000000010 RSI: 00002000000000c0 RDI: 0000000000000011 RBP: 00007f14f9211e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f14f93b6038 R14: 00007f14f93b5fa0 R15: 00007ffc5df5efd8