rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=c254/1/0x4000000000000000 softirq=166244/166246 fqs=1 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P27715 P26341/1:b..l rcu: (detected by 1, t=10502 jiffies, g=126729, q=203 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 27715 Comm: syz.0.5656 Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x2c/0x80 kernel/locking/spinlock.c:194 Code: 1e fa 55 48 89 f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 a6 5c 0f f6 48 89 df e8 8e b0 0f f6 f7 c5 00 02 00 00 75 23 9c 58 c4 02 75 37 bf 01 00 00 00 e8 f5 d2 ff f5 65 8b 05 8e d9 46 08 RSP: 0000:ffffc90000007e28 EFLAGS: 00000046 RAX: 0000000000000046 RBX: ffff8880b8427c80 RCX: ffffffff8198d763 RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffff8880b8427c80 RBP: 0000000000000046 R08: 0000000000000000 R09: ffffed1017084f90 R10: ffff8880b8427c83 R11: 0000000000000001 R12: ffff8880b8427c80 R13: 1861c02d9c000000 R14: ffff888064fb9340 R15: ffffffff89994ed0 FS: 00007fb6035da6c0(0000) GS:ffff888124720000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2c40cff8 CR3: 0000000057a1d000 CR4: 00000000003526f0 DR0: 0000000061812e20 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: __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+0x10b/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:finish_task_switch.isra.0+0x22a/0xc10 kernel/sched/core.c:5265 Code: fb 09 00 00 44 8b 05 09 85 1f 0f 45 85 c0 0f 85 be 01 00 00 4c 89 e7 e8 a4 f6 ff ff e8 cf cb 39 00 fb 65 48 8b 1d be 12 46 12 <48> 8d bb 18 16 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0000:ffffc900048aec30 EFLAGS: 00000202 RAX: 0000000000001257 RBX: ffff88802bd28000 RCX: 0000000000000007 RDX: 0000000000000000 RSI: ffffffff8de2ff26 RDI: ffffffff8c1573e0 RBP: ffffc900048aec78 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff90a94057 R11: 0000000000000001 R12: ffff8880b843a2c0 R13: ffff888058cf2440 R14: 0000000000000001 R15: ffff8880b843b130 context_switch kernel/sched/core.c:5400 [inline] __schedule+0x1172/0x5dd0 kernel/sched/core.c:6786 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7109 irqentry_exit+0x36/0x90 kernel/entry/common.c:307 asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:709 RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5875 Code: 76 37 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 32 b6 10 0f 0f 82 74 02 00 00 8b 35 1a e8 10 0f 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 c9 75 37 12 0f 85 c7 02 00 00 48 83 c4 RSP: 0018:ffffc900048aef10 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e5c4e00 RCX: 000000004e00f4b7 RDX: 0000000000000000 RSI: ffffffff8de0aca5 RDI: ffffffff8c1573e0 RBP: 0000000000000002 R08: c5582be4a94f9ee0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xd1/0x20a0 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 save_stack+0x160/0x1f0 mm/page_owner.c:156 __set_page_owner+0x91/0x550 mm/page_owner.c:329 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704 prep_new_page mm/page_alloc.c:1712 [inline] get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419 alloc_frozen_pages_noprof mm/mempolicy.c:2490 [inline] alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2510 get_free_pages_noprof+0x10/0xb0 mm/page_alloc.c:5018 selinux_genfs_get_sid security/selinux/hooks.c:1328 [inline] inode_doinit_with_dentry+0x8d6/0x12e0 security/selinux/hooks.c:1551 selinux_d_instantiate+0x26/0x30 security/selinux/hooks.c:6495 security_d_instantiate+0x142/0x1a0 security/security.c:4079 d_splice_alias+0x93/0xf80 fs/dcache.c:2997 proc_lookup_de+0x29e/0x320 fs/proc/generic.c:258 proc_tgid_net_lookup+0x75/0x120 fs/proc/proc_net.c:297 lookup_open.isra.0+0x4d7/0x1580 fs/namei.c:3695 open_last_lookups fs/namei.c:3816 [inline] path_openat+0x893/0x2cb0 fs/namei.c:4052 do_filp_open+0x20b/0x470 fs/namei.c:4082 do_sys_openat2+0x11b/0x1d0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1463 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: 0033:0x7fb60278d310 Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 49 94 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 9c 94 02 00 8b 44 RSP: 002b:00007fb6035d9f10 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb60278d310 RDX: 0000000000000002 RSI: 00007fb6035d9fa0 RDI: 00000000ffffff9c RBP: 00007fb6035d9fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fb6029b6080 R15: 00007ffea8061a28 task:kworker/u8:9 state:R running task stack:24424 pid:26341 tgid:26341 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x116a/0x5dd0 kernel/sched/core.c:6786 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7109 irqentry_exit+0x36/0x90 kernel/entry/common.c:307 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:lock_release+0x183/0x2f0 kernel/locking/lockdep.c:5896 Code: 0f c1 05 48 bd 37 12 83 f8 01 0f 85 1d 01 00 00 9c 58 f6 c4 02 0f 85 08 01 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 5d 7b 37 12 0f 85 58 01 00 00 48 83 c4 18 5b 41 5c 41 RSP: 0000:ffffc900043d7ae0 EFLAGS: 00000206 RAX: c37f95ff9955fc00 RBX: ffffffff8e5c4e00 RCX: ffffc900043d7aec RDX: 0000000000000002 RSI: ffffffff8de0aca5 RDI: ffffffff8c1573e0 RBP: 000000000000023c R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffffffff8b53bf25 R13: 0000000000000206 R14: ffff888058cf2440 R15: 0000000000000003 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline] batadv_nc_worker+0x89a/0x1030 net/batman-adv/network-coding.c:719 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:syz.0.5656 state:R running task stack:27160 pid:27715 tgid:27711 ppid:17938 task_flags:0x400140 flags:0x00004008 Call Trace: rcu: rcu_preempt kthread starved for 10500 jiffies! g126729 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:27368 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x116a/0x5dd0 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6879 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+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 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: 17268 Comm: syz-executor Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x20 kernel/kcov.c:313 Code: 0c 24 0f b7 d6 0f b7 f7 bf 03 00 00 00 e9 58 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 0c 24 89 f2 89 fe bf 05 00 00 00 e9 2a fe ff ff RSP: 0018:ffffc9000f137748 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffff8880b84421e0 RCX: ffffffff81afd3cd RDX: ffff88805edca440 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000 R13: 0000000000000003 R14: ffffed101708843d R15: ffff8880b853b580 FS: 000055555f4cf500(0000) GS:ffff888124820000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f03800e56c0 CR3: 000000005166b000 CR4: 00000000003526f0 Call Trace: csd_lock_wait kernel/smp.c:340 [inline] smp_call_function_many_cond+0xd9d/0x1510 kernel/smp.c:885 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x4a0/0x1790 arch/x86/mm/tlb.c:1451 dup_mmap+0xfa2/0x21d0 mm/mmap.c:1877 dup_mm kernel/fork.c:1477 [inline] copy_mm kernel/fork.c:1529 [inline] copy_process+0x4081/0x7650 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: 0033:0x7f037f385213 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007fff9259be48 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f037f385213 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 000055555f4cf7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 00000000001c96b6 R15: 00007fff9259bfe0