rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=e90c/1/0x4000000000000000 softirq=33433/33435 fqs=1 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7372/1:b..l rcu: (detected by 0, t=10505 jiffies, g=45033, q=25 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5393 Comm: kworker/u4:13 Not tainted 6.4.0-rc4-syzkaller-00031-g8b817fded42d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Workqueue: writeback wb_workfn (flush-8:0) RIP: 0010:rcu_dynticks_curr_cpu_in_eqs include/linux/context_tracking.h:122 [inline] RIP: 0010:rcu_is_watching+0x10/0xb0 kernel/rcu/tree.c:695 Code: a6 7d f8 02 e9 2b ff ff ff e8 1c cf 3a 09 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 41 57 41 56 53 65 ff 05 d8 58 8f 7e 0b e9 3a 09 89 c3 83 f8 08 73 76 49 bf 00 00 00 00 00 fc ff df RSP: 0018:ffffc900001e0b40 EFLAGS: 00000083 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff816b3910 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e55c868 RBP: ffffc900001e0c90 R08: dffffc0000000000 R09: fffffbfff1cab90e R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff9200003c178 R13: ffffffff817b413b R14: ffffc900001e0cc0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000000 CR3: 000000003a204000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0xbf/0x9d0 kernel/locking/lockdep.c:5716 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x79/0x140 kernel/locking/spinlock.c:194 debug_hrtimer_deactivate kernel/time/hrtimer.c:425 [inline] debug_deactivate+0x1b/0x1f0 kernel/time/hrtimer.c:481 __run_hrtimer kernel/time/hrtimer.c:1653 [inline] __hrtimer_run_queues+0x321/0xd10 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x396/0x980 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline] __sysvec_apic_timer_interrupt+0x13f/0x480 arch/x86/kernel/apic/apic.c:1112 sysvec_apic_timer_interrupt+0x90/0xb0 arch/x86/kernel/apic/apic.c:1106 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:finish_lock_switch+0x95/0x110 kernel/sched/core.c:5096 Code: 45 31 c9 68 47 70 61 81 e8 28 a1 09 00 48 83 c4 08 4c 89 ff e8 6c a8 fe ff eb 32 4c 89 ff e8 02 9f 57 09 e8 bd c0 30 00 fb 5b <41> 5c 41 5d 41 5e 41 5f c3 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 83 RSP: 0018:ffffc9000ae5e718 EFLAGS: 00000282 RAX: b536b9ac9d398300 RBX: ffff88801eb03bb4 RCX: ffffffff816b826a RDX: dffffc0000000000 RSI: ffffffff8aea8e20 RDI: ffffffff8b384500 RBP: ffffc9000ae5e790 R08: dffffc0000000000 R09: fffffbfff2065064 R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000 R13: 1ffff110173279e3 R14: ffff8880b993cf18 R15: ffff8880b983c1c0 finish_task_switch+0x134/0x650 kernel/sched/core.c:5213 context_switch kernel/sched/core.c:5346 [inline] __schedule+0x1883/0x4900 kernel/sched/core.c:6669 schedule+0xc3/0x180 kernel/sched/core.c:6745 io_schedule+0x8c/0x100 kernel/sched/core.c:8979 folio_wait_bit_common+0x86c/0x12b0 mm/filemap.c:1301 mpage_prepare_extent_to_map+0x846/0x1ba0 fs/ext4/inode.c:2447 ext4_do_writepages+0xcf7/0x3da0 fs/ext4/inode.c:2656 ext4_writepages+0x203/0x3e0 fs/ext4/inode.c:2792 do_writepages+0x3a6/0x670 mm/page-writeback.c:2551 __writeback_single_inode+0x155/0xfa0 fs/fs-writeback.c:1603 writeback_sb_inodes+0x8e3/0x11d0 fs/fs-writeback.c:1894 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:1965 wb_writeback+0x46c/0xc70 fs/fs-writeback.c:2070 wb_check_start_all fs/fs-writeback.c:2192 [inline] wb_do_writeback fs/fs-writeback.c:2218 [inline] wb_workfn+0x98f/0xff0 fs/fs-writeback.c:2251 process_one_work+0x8a0/0x10e0 kernel/workqueue.c:2405 worker_thread+0xa63/0x1210 kernel/workqueue.c:2552 kthread+0x2b8/0x350 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 task:kworker/u4:20 state:R running task stack:22040 pid:7372 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5343 [inline] __schedule+0x187b/0x4900 kernel/sched/core.c:6669 preempt_schedule_irq+0xfb/0x1b0 kernel/sched/core.c:6981 irqentry_exit+0x57/0x80 kernel/entry/common.c:433 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:lock_acquire+0x25a/0x520 kernel/locking/lockdep.c:5709 Code: 2b 00 74 08 4c 89 f7 e8 c4 3d 78 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc90005537a20 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff92000aa6f50 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: ffffffff8aea9fa0 RDI: ffffffff8b384500 RBP: ffffc90005537b70 R08: dffffc0000000000 R09: fffffbfff206504d R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000aa6f4c R13: dffffc0000000000 R14: ffffc90005537a80 R15: 0000000000000246 rcu_lock_acquire+0x2e/0x40 include/linux/rcupdate.h:327 rcu_read_lock include/linux/rcupdate.h:773 [inline] batadv_nc_process_nc_paths+0xb8/0x350 net/batman-adv/network-coding.c:687 batadv_nc_worker+0x3d8/0x5c0 net/batman-adv/network-coding.c:728 process_one_work+0x8a0/0x10e0 kernel/workqueue.c:2405 worker_thread+0xa63/0x1210 kernel/workqueue.c:2552 kthread+0x2b8/0x350 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 rcu: rcu_preempt kthread starved for 10500 jiffies! g45033 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:25728 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5343 [inline] __schedule+0x187b/0x4900 kernel/sched/core.c:6669 schedule+0xc3/0x180 kernel/sched/core.c:6745 schedule_timeout+0x1bd/0x310 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x2c6/0x1010 kernel/rcu/tree.c:1609 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:1808 kthread+0x2b8/0x350 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 6833 Comm: kworker/u4:18 Not tainted 6.4.0-rc4-syzkaller-00031-g8b817fded42d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:285 [inline] RIP: 0010:smp_call_function_many_cond+0x14fb/0x1f60 kernel/smp.c:828 Code: 45 8b 34 24 44 89 f6 83 e6 01 31 ff e8 4e 0f 0b 00 41 83 e6 01 49 be 00 00 00 00 00 fc ff df 75 07 e8 89 0b 0b 00 eb 38 f3 90 <42> 0f b6 04 33 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 6d 0b RSP: 0018:ffffc9000c3d77c0 EFLAGS: 00000293 RAX: ffffffff818071b3 RBX: 1ffff110173285c5 RCX: ffff88807b5e1dc0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000c3d79c0 R08: ffffffff81807182 R09: fffffbfff206504d R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8880b9942e28 R13: ffff8880b983d308 R14: dffffc0000000000 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000040 CR3: 000000000cd30000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:996 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1770 [inline] text_poke_bp_batch+0x2bf/0x950 arch/x86/kernel/alternative.c:1970 text_poke_flush arch/x86/kernel/alternative.c:2161 [inline] text_poke_finish+0x1a/0x30 arch/x86/kernel/alternative.c:2168 arch_jump_label_transform_apply+0x17/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x132/0x250 kernel/jump_label.c:205 static_key_enable+0x1a/0x20 kernel/jump_label.c:218 toggle_allocation_gate+0xb5/0x250 mm/kfence/core.c:831 process_one_work+0x8a0/0x10e0 kernel/workqueue.c:2405 worker_thread+0xa63/0x1210 kernel/workqueue.c:2552 kthread+0x2b8/0x350 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308