rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 ticks this GP) idle=7c74/1/0x4000000000000000 softirq=22159/22159 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6801/1:b..l P6805/1:b..l P5820/1:b..l rcu: (detected by 1, t=10502 jiffies, g=13309, q=269 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5821 Comm: udevd Not tainted 6.16.0-rc1-syzkaller-00203-g4774cfe3543a #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:102 [inline] RIP: 0010:do_raw_spin_unlock+0x9c/0x230 kernel/locking/spinlock_debug.c:141 Code: d0 7c 08 84 d2 0f 85 6c 01 00 00 8b 03 85 c0 0f 84 f5 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8d 63 10 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 67 01 00 00 65 48 8b 05 8a f5 33 12 48 39 43 10 RSP: 0018:ffffc90000007e08 EFLAGS: 00000802 RAX: dffffc0000000000 RBX: ffff8880b8427c80 RCX: ffffffff8198ca33 RDX: 1ffff11017084f92 RSI: 0000000000000004 RDI: ffff8880b8427c80 RBP: 0000000000000046 R08: 0000000000000000 R09: ffffed1017084f90 R10: ffff8880b8427c83 R11: 0000000000000001 R12: ffff8880b8427c90 R13: 185675b2b99d6b29 R14: ffff88807ca73340 R15: ffffffff8992b740 FS: 00007fa53ef60880(0000) GS:ffff888124754000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2f50aff8 CR3: 000000005cba4000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_unlock_irqrestore+0x22/0x80 kernel/locking/spinlock.c:194 __run_hrtimer kernel/time/hrtimer.c:1757 [inline] __hrtimer_run_queues+0x529/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 76 d0 15 f6 48 89 df e8 5e 24 16 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 95 44 06 f6 65 8b 05 8e 1a 4a 08 85 c0 74 16 5b RSP: 0018:ffffc900046afae8 EFLAGS: 00000246 RAX: 0000000000000002 RBX: ffffffff9af73cb8 RCX: 0000000000000007 RDX: 0000000000000000 RSI: ffffffff8de1993c RDI: ffffffff8c1575a0 RBP: 0000000000000206 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff90a81057 R11: ffffffff9af73cb8 R12: 0000000000000001 R13: ffff8880572509b0 R14: ffffffff9af73cb0 R15: 1ffff920008d5f64 debug_object_activate+0x2ec/0x4c0 lib/debugobjects.c:836 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline] __call_rcu_common.constprop.0+0x2c/0x9f0 kernel/rcu/tree.c:3075 security_inode_free+0xa4/0x170 security/security.c:1735 __destroy_inode+0x201/0x730 fs/inode.c:371 destroy_inode+0x91/0x1b0 fs/inode.c:394 evict+0x5b4/0x920 fs/inode.c:834 iput_final fs/inode.c:1898 [inline] iput fs/inode.c:1924 [inline] iput+0x521/0x880 fs/inode.c:1910 do_unlinkat+0x518/0x6a0 fs/namei.c:4657 __do_sys_unlink fs/namei.c:4696 [inline] __se_sys_unlink fs/namei.c:4694 [inline] __x64_sys_unlink+0xc5/0x110 fs/namei.c:4694 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa53e915937 Code: 00 00 e9 a9 fd ff ff 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 5f 00 00 00 0f 05 c3 0f 1f 84 00 00 00 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 91 b4 0d 00 f7 d8 64 89 02 b8 RSP: 002b:00007ffcf8f6fd38 EFLAGS: 00000202 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000559d3bcd10e0 RCX: 00007fa53e915937 RDX: 0000000000000001 RSI: 0000559d100ed67f RDI: 00007ffcf8f6fd40 RBP: 00000000000000f0 R08: 0000000000000064 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffcf8f6fd40 R13: 0000000003938700 R14: 0000559d10108100 R15: 0000559d10108140 task:syz-executor state:R running task stack:23816 pid:5820 tgid:5820 ppid:5810 task_flags:0x400140 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7108 irqentry_exit+0x36/0x90 kernel/entry/common.c:307 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:check_kcov_mode kernel/kcov.c:185 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x3b/0x70 kernel/kcov.c:217 Code: 8b 05 29 a4 10 12 a9 00 01 ff 00 74 1d f6 c4 01 74 43 a9 00 00 0f 00 75 3c a9 00 00 f0 00 75 35 8b 82 3c 16 00 00 85 c0 74 2b <8b> 82 18 16 00 00 83 f8 02 75 20 48 8b 8a 20 16 00 00 8b 92 1c 16 RSP: 0018:ffffc9000463f690 EFLAGS: 00000246 RAX: 0000000080000000 RBX: 0000000000000001 RCX: ffffffff820a29d5 RDX: ffff888026c24880 RSI: ffffffff820a2722 RDI: 0000000000000001 RBP: 0000000000000004 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000 R13: dffffc0000000000 R14: ffff88806adfa760 R15: 00007f4ee5d28000 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] pte_unmap include/linux/pgtable.h:136 [inline] copy_pte_range mm/memory.c:1206 [inline] copy_pmd_range mm/memory.c:1267 [inline] copy_pud_range mm/memory.c:1304 [inline] copy_p4d_range mm/memory.c:1328 [inline] copy_page_range+0x13e2/0x5740 mm/memory.c:1416 dup_mmap+0xe88/0x21d0 mm/mmap.c:1838 dup_mm kernel/fork.c:1477 [inline] copy_mm kernel/fork.c:1529 [inline] copy_process+0x4081/0x76a0 kernel/fork.c:2169 kernel_clone+0xfc/0x960 kernel/fork.c:2599 __do_sys_clone+0xce/0x120 kernel/fork.c:2742 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4ee6f85193 RSP: 002b:00007ffd5d6288e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4ee6f85193 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 000055558794e7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 0000000000028a49 R15: 00007ffd5d628a80 task:syz.4.213 state:R running task stack:27752 pid:6805 tgid:6796 ppid:5827 task_flags:0x400140 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6965 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0x107/0x120 kernel/softirq.c:414 local_bh_enable include/linux/bottom_half.h:33 [inline] tun_rx_batched.isra.0+0x3ff/0x740 drivers/net/tun.c:1510 tun_get_user+0x28a2/0x3b80 drivers/net/tun.c:1938 tun_chr_write_iter+0xdc/0x210 drivers/net/tun.c:1984 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x6c4/0x1150 fs/read_write.c:686 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0d9b58d3df RSP: 002b:00007f0d9c38e000 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f0d9b7b6160 RCX: 00007f0d9b58d3df RDX: 000000000000002a RSI: 0000200000000080 RDI: 00000000000000c8 RBP: 00007f0d9b610b39 R08: 0000000000000000 R09: 0000000000000000 R10: 000000000000002a R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f0d9b7b6160 R15: 00007ffee746bde8 task:syz.1.209 state:R running task stack:25600 pid:6801 tgid:6790 ppid:5812 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 preempt_schedule_notrace+0x62/0xe0 kernel/sched/core.c:7058 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:746 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0x201/0x2f0 kernel/locking/lockdep.c:5882 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+0x3f9/0x20a0 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:345 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4204 alloc_empty_file+0x55/0x1e0 fs/file_table.c:234 alloc_file fs/file_table.c:351 [inline] alloc_file_pseudo+0x13a/0x230 fs/file_table.c:380 __anon_inode_getfile+0xf7/0x3a0 fs/anon_inodes.c:153 __anon_inode_getfd fs/anon_inodes.c:278 [inline] anon_inode_getfd+0x52/0xb0 fs/anon_inodes.c:313 bpf_prog_new_fd kernel/bpf/syscall.c:2483 [inline] bpf_prog_new_fd+0x45/0x60 kernel/bpf/syscall.c:2475 bpf_prog_load+0xf95/0x2490 kernel/bpf/syscall.c:3002 __sys_bpf+0x433c/0x4d80 kernel/bpf/syscall.c:5836 __do_sys_bpf kernel/bpf/syscall.c:5943 [inline] __se_sys_bpf kernel/bpf/syscall.c:5941 [inline] __x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:5941 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6bdc38e929 RSP: 002b:00007f6bdd1a2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f6bdc5b6080 RCX: 00007f6bdc38e929 RDX: 0000000000000048 RSI: 00002000000054c0 RDI: 0000000000000005 RBP: 00007f6bdc410b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f6bdc5b6080 R15: 00007ffd54100b48 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g13309 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=10273 rcu: rcu_preempt kthread starved for 10502 jiffies! g13309 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28520 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6878 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245