rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (4 ticks this GP) idle=e704/1/0x4000000000000000 softirq=47252/47255 fqs=173 rcu: (detected by 1, t=10502 jiffies, g=40825, q=526 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 9466 Comm: syz.0.1042 Not tainted 6.12.0-rc3-syzkaller-00140-g07d6bf634bc8 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: 89 fb e8 23 00 00 00 48 8b 3d 54 0a 9d 0c 48 89 de 5b e9 83 ca 5d 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 c0 d7 03 00 65 8b 15 b0 ef RSP: 0018:ffffc90000007c88 EFLAGS: 00000002 RAX: 0000000000010000 RBX: 0000000000000001 RCX: ffff88802f739e00 RDX: ffff88802f739e00 RSI: 0000000000000001 RDI: 0000000000000000 RBP: dffffc0000000000 R08: ffffffff89cbdf18 R09: fffff52000000f80 R10: dffffc0000000000 R11: fffff52000000f80 R12: 0000000000000002 R13: ffffffff89cbde40 R14: ffff888026dc4340 R15: ffff88802f73a8c8 FS: 00007f2f498d46c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2d2c18 CR3: 000000006537c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: advance_sched+0xe5/0xca0 net/sched/sch_taprio.c:925 __run_hrtimer kernel/time/hrtimer.c:1691 [inline] __hrtimer_run_queues+0x59b/0xd50 kernel/time/hrtimer.c:1755 hrtimer_interrupt+0x396/0x990 kernel/time/hrtimer.c:1817 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1026 [inline] __sysvec_apic_timer_interrupt+0x110/0x3f0 arch/x86/kernel/apic/apic.c:1043 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1037 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+0xd8/0x140 kernel/locking/spinlock.c:194 Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 4e 87 2e f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 a3 29 93 f5 65 8b 05 b4 c3 33 74 85 c0 74 43 48 c7 04 24 0e 36 RSP: 0018:ffffc900032fede0 EFLAGS: 00000206 RAX: ddee9c8c440aa800 RBX: 1ffff9200065fdc0 RCX: ffffffff8170ce6a RDX: dffffc0000000000 RSI: ffffffff8c0acac0 RDI: 0000000000000001 RBP: ffffc900032fee70 R08: ffffffff942c996f R09: 1ffffffff285932d R10: dffffc0000000000 R11: fffffbfff285932e R12: dffffc0000000000 R13: 1ffff9200065fdbc R14: ffffc900032fee00 R15: 0000000000000246 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] taprio_change+0x26d2/0x44c0 net/sched/sch_taprio.c:1972 taprio_init+0x9da/0xc80 net/sched/sch_taprio.c:2113 qdisc_create+0x9d4/0x11a0 net/sched/sch_api.c:1360 tc_modify_qdisc+0xa26/0x1e40 net/sched/sch_api.c:1782 rtnetlink_rcv_msg+0x73f/0xcf0 net/core/rtnetlink.c:6675 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2551 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline] netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1357 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1901 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:744 ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2607 ___sys_sendmsg net/socket.c:2661 [inline] __sys_sendmsg+0x292/0x380 net/socket.c:2690 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2f48b7dff9 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:00007f2f498d4038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f2f48d35f80 RCX: 00007f2f48b7dff9 RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000005 RBP: 00007f2f48bf0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f2f48d35f80 R15: 00007ffedec56648 rcu: rcu_preempt kthread starved for 9640 jiffies! g40825 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:24976 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5322 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6682 __schedule_loop kernel/sched/core.c:6759 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6774 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 5391 Comm: kworker/u8:11 Not tainted 6.12.0-rc3-syzkaller-00140-g07d6bf634bc8 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: writeback wb_workfn (flush-8:0) RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x19f3/0x2ca0 kernel/smp.c:884 Code: 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 56 f3 0b 00 41 83 e4 01 49 bc 00 00 00 00 00 fc ff df 75 07 e8 01 ef 0b 00 eb 38 f3 90 <42> 0f b6 04 23 84 c0 75 11 41 f7 45 00 01 00 00 00 74 1e e8 e5 ee RSP: 0018:ffffc900040e5fa0 EFLAGS: 00000293 RAX: ffffffff8188f91b RBX: 1ffff110170c8ca1 RCX: ffff8880273c1e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900040e61a0 R08: ffffffff8188f8ea R09: 1ffff9200081cbe4 R10: dffffc0000000000 R11: ffffffff81432160 R12: dffffc0000000000 R13: ffff8880b8646508 R14: ffff8880b873fc80 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555875345c8 CR3: 000000000e734000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1051 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:938 [inline] flush_tlb_mm_range+0x329/0x5c0 arch/x86/mm/tlb.c:1024 flush_tlb_page arch/x86/include/asm/tlbflush.h:254 [inline] ptep_clear_flush+0x11a/0x170 mm/pgtable-generic.c:101 page_vma_mkclean_one+0x58a/0x9a0 mm/rmap.c:1044 page_mkclean_one+0x280/0x420 mm/rmap.c:1085 rmap_walk_file+0x52f/0x9f0 mm/rmap.c:2700 rmap_walk mm/rmap.c:2718 [inline] folio_mkclean+0x262/0x440 mm/rmap.c:1117 folio_clear_dirty_for_io+0x22b/0xd00 mm/page-writeback.c:3024 mpage_submit_folio+0x88/0x230 fs/ext4/inode.c:1902 mpage_process_page_bufs+0x6c9/0x8d0 fs/ext4/inode.c:2034 mpage_prepare_extent_to_map+0xec7/0x1c80 fs/ext4/inode.c:2535 ext4_do_writepages+0xc55/0x3d20 fs/ext4/inode.c:2677 ext4_writepages+0x213/0x3c0 fs/ext4/inode.c:2813 do_writepages+0x35d/0x870 mm/page-writeback.c:2683 __writeback_single_inode+0x14f/0x10d0 fs/fs-writeback.c:1658 writeback_sb_inodes+0x80c/0x1370 fs/fs-writeback.c:1954 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2025 wb_writeback+0x42f/0xbd0 fs/fs-writeback.c:2136 wb_check_old_data_flush fs/fs-writeback.c:2240 [inline] wb_do_writeback fs/fs-writeback.c:2293 [inline] wb_workfn+0xba1/0x1090 fs/fs-writeback.c:2321 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244