rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=369/1/0x4000000000000000 softirq=90790/90791 fqs=18 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P30350/1:b..l (detected by 1, t=10502 jiffies, g=121121, q=299) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 17004 Comm: kworker/u4:55 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: bat_events batadv_nc_worker RIP: 0010:__lock_acquire+0x36f/0x7c60 kernel/locking/lockdep.c:4946 Code: 04 80 48 8b 4c 24 30 4c 8d a4 c1 f0 0a 00 00 48 8d 8c c1 10 0b 00 00 48 89 4c 24 18 48 c1 e9 03 48 89 4c 24 58 42 0f b6 04 01 <84> c0 0f 85 10 63 00 00 4c 8b 7d 18 48 89 54 24 60 41 89 d6 b8 00 RSP: 0000:ffffc900000078c0 EFLAGS: 00000806 RAX: 0000000000000000 RBX: ffff88801e2e4b00 RCX: 1ffff1100b804524 RDX: 000000000000103f RSI: 0000000000000000 RDI: ffff88801e2e4b00 RBP: ffffc90000007b10 R08: dffffc0000000000 R09: 0000000000000001 R10: fffffbfff1ad33a6 R11: 1ffffffff1ad33a5 R12: ffff88805c022900 R13: 0000000000000000 R14: ffff88805c0228f8 R15: 000000000000000a FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000008d030 CR3: 000000005b1b7000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:364 [inline] advance_sched+0x47/0x940 net/sched/sch_taprio.c:716 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:lock_release+0x584/0x870 kernel/locking/lockdep.c:5647 Code: 00 00 00 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 75 75 f7 44 24 50 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 2f 00 00 00 00 66 43 c7 44 2f 09 00 00 43 c6 44 2f 0b 00 RSP: 0000:ffffc9000425fac0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: c422640388757846 RCX: dbad569255d2f100 RDX: 0000000000000002 RSI: ffffffff8a0b2f00 RDI: ffffffff8a59e580 RBP: ffffc9000425fbd0 R08: dffffc0000000000 R09: fffffbfff1ad33a6 R10: fffffbfff1ad33a6 R11: 1ffffffff1ad33a5 R12: ffff88805c022900 R13: dffffc0000000000 R14: ffff88805c0228a0 R15: 1ffff9200084bf64 rcu_read_unlock include/linux/rcupdate.h:773 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:416 [inline] batadv_nc_worker+0x25b/0x5c0 net/batman-adv/network-coding.c:723 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 task:syz.2.11315 state:R running task stack:23360 pid:30350 ppid: 4190 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681 RIP: 0010:lock_acquire+0x1f2/0x3f0 kernel/locking/lockdep.c:5627 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f6 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b RSP: 0018:ffffc900030cf120 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 806b0c9cc783f700 RDX: 0000000000000000 RSI: ffffffff8a0b2f00 RDI: ffffffff8a59e580 RBP: ffffc900030cf238 R08: dffffc0000000000 R09: fffffbfff1ff7c19 R10: fffffbfff1ff7c19 R11: 1ffffffff1ff7c18 R12: ffffffff8c11c760 R13: 1ffff92000619e30 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire+0x20/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] percpu_ref_put_many include/linux/percpu-refcount.h:317 [inline] percpu_ref_put+0x16/0x150 include/linux/percpu-refcount.h:338 __mem_cgroup_uncharge_list+0x6c/0xc0 mm/memcontrol.c:7004 mem_cgroup_uncharge_list include/linux/memcontrol.h:720 [inline] release_pages+0x1843/0x1bb0 mm/swap.c:962 __pagevec_release+0x6d/0xe0 mm/swap.c:983 pagevec_release include/linux/pagevec.h:81 [inline] shmem_undo_range+0x5cb/0x1880 mm/shmem.c:964 shmem_truncate_range mm/shmem.c:1063 [inline] shmem_evict_inode+0x20d/0xa00 mm/shmem.c:1145 evict+0x485/0x870 fs/inode.c:647 __dentry_kill+0x431/0x650 fs/dcache.c:586 dentry_kill+0xb8/0x290 fs/dcache.c:-1 dput+0xd8/0x1a0 fs/dcache.c:893 __fput+0x5ee/0x930 fs/file_table.c:319 task_work_run+0x125/0x1a0 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0x61e/0x20a0 kernel/exit.c:883 do_group_exit+0x12e/0x300 kernel/exit.c:997 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:320 exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1504 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606 RIP: 0033:0x7f2680f1c6d1 RSP: 002b:0000000000000040 EFLAGS: 00010217 RAX: 0000000000000000 RBX: 00007f2681172fa0 RCX: 00007f2680f1c6c9 RDX: 0000000000000000 RSI: 0000000000000040 RDI: 0000000081248080 RBP: 00007f2680f9ef91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007f2681173038 R14: 00007f2681172fa0 R15: 00007fff822df9b8 rcu: rcu_preempt kthread starved for 10465 jiffies! g121121 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:26688 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 30446 Comm: syz.1.11339 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0xb88/0xd70 kernel/smp.c:969 Code: b6 44 05 00 84 c0 0f 85 9d 00 00 00 41 8b 1c 24 89 de 83 e6 01 31 ff e8 66 49 0b 00 83 e3 01 75 07 e8 fc 45 0b 00 eb 43 f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 44 05 00 84 c0 75 11 41 f7 RSP: 0018:ffffc90003bdf4e0 EFLAGS: 00000293 RAX: ffffffff816c863b RBX: 0000000000000001 RCX: ffff88805b0a1dc0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003bdf620 R08: dffffc0000000000 R09: ffffed101722767b R10: ffffed101722767b R11: 1ffff1101722767a R12: ffff8880b9042848 R13: 1ffff11017208509 R14: ffff8880b913b3c0 R15: 0000000000000000 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1134 __flush_tlb_multi arch/x86/include/asm/paravirt.h:87 [inline] flush_tlb_multi arch/x86/mm/tlb.c:946 [inline] flush_tlb_mm_range+0x360/0x560 arch/x86/mm/tlb.c:1034 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly+0x1b1/0x3f0 include/asm-generic/tlb.h:430 tlb_flush_mmu mm/mmu_gather.c:246 [inline] tlb_finish_mmu+0xc5/0x2e0 mm/mmu_gather.c:338 exit_mmap+0x3a6/0x5f0 mm/mmap.c:3218 __mmput+0x115/0x3b0 kernel/fork.c:1127 exit_mm+0x567/0x6c0 kernel/exit.c:550 do_exit+0x5a1/0x20a0 kernel/exit.c:870 do_group_exit+0x12e/0x300 kernel/exit.c:997 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f27994c76c9 Code: Unable to access opcode bytes at RIP 0x7f27994c769f. RSP: 002b:00007f279772e038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: 000000000000003c RBX: 00007f279971dfa0 RCX: 00007f27994c76c9 RDX: 0000000000000030 RSI: 0000200000000100 RDI: 0000000000000005 RBP: 00007f2799549f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f279971e038 R14: 00007f279971dfa0 R15: 00007ffcb0d75d58