rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=4e3/1/0x4000000000000000 softirq=23914/23915 fqs=72 (detected by 1, t=10505 jiffies, g=27633, q=443) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9830 Comm: syz.6.1336 Not tainted 5.15.176-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:_raw_spin_unlock_irqrestore+0xa/0x130 kernel/locking/spinlock.c:193 Code: dc cf 0e f7 65 8b 05 ed b2 b9 75 85 c0 74 02 5b c3 e8 ba cf b7 f6 5b c3 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 57 41 56 41 55 <41> 54 53 48 83 e4 e0 48 83 ec 60 49 89 f7 48 89 fb 65 48 8b 04 25 RSP: 0018:ffffc90000007d38 EFLAGS: 00000046 RAX: 1ffff1100f5b406d RBX: ffff88807ada0368 RCX: 0000000000000001 RDX: 0000000000010000 RSI: 0000000000000046 RDI: ffff8880b8e2a200 RBP: ffffc90000007d50 R08: ffffffff816f8850 R09: fffffbfff1c14d56 R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8880b8e2a200 R13: ffffffff888c78b0 R14: ffff88807ada0340 R15: dffffc0000000000 FS: 00007f53a97d66c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33e1bff8 CR3: 0000000056235000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1684 [inline] __hrtimer_run_queues+0x48c/0xcf0 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x13b/0x4b0 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:finish_lock_switch+0x91/0x100 kernel/sched/core.c:4782 Code: 45 31 c9 68 c7 ba 59 81 e8 1c 12 09 00 48 83 c4 08 4c 89 ff e8 90 db fe ff 66 90 4c 89 ff e8 b6 01 ef 08 e8 41 48 2d 00 fb 5b <41> 5c 41 5d 41 5e 41 5f c3 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 87 RSP: 0018:ffffc90002f7f218 EFLAGS: 00000282 RAX: 4df1cb0a006d5300 RBX: ffff888075263bb4 RCX: ffffffff81633db8 RDX: dffffc0000000000 RSI: ffffffff8aab2b80 RDI: ffffffff8af9f340 RBP: ffffc90002f7f290 R08: dffffc0000000000 R09: fffffbfff2131437 R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000 R13: 1ffff110171c760b R14: ffff8880b8e3b058 R15: ffff8880b8e3a300 finish_task_switch+0x134/0x630 kernel/sched/core.c:4899 context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12cc/0x45b0 kernel/sched/core.c:6373 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6549 preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6574 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x128/0x130 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:418 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x121/0x1c0 kernel/sched/wait.c:205 __unix_dgram_recvmsg+0x5fe/0x1260 net/unix/af_unix.c:2331 ____sys_recvmsg+0x286/0x530 ___sys_recvmsg+0x1ec/0x690 net/socket.c:2697 do_recvmmsg+0x36f/0x8f0 net/socket.c:2791 __sys_recvmmsg net/socket.c:2870 [inline] __do_sys_recvmmsg net/socket.c:2893 [inline] __se_sys_recvmmsg net/socket.c:2886 [inline] __x64_sys_recvmmsg+0x195/0x240 net/socket.c:2886 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f53ab986d29 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:00007f53a97d6038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f53abb77080 RCX: 00007f53ab986d29 RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 00007f53aba02b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f53abb77080 R15: 00007ffe3e3768a8 rcu: rcu_preempt kthread timer wakeup didn't happen for 10124 jiffies! g27633 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=18713 rcu: rcu_preempt kthread starved for 10125 jiffies! g27633 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26144 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5027 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373 schedule+0x11b/0x1f0 kernel/sched/core.c:6456 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 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: 9465 Comm: kworker/u4:2 Not tainted 5.15.176-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619 update_process_times+0x196/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x13b/0x4b0 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+0xa93/0xd90 kernel/smp.c:969 Code: 04 03 84 c0 0f 85 84 00 00 00 45 8b 7d 00 44 89 fe 83 e6 01 31 ff e8 3c d6 0b 00 41 83 e7 01 75 07 e8 d1 d2 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00 RSP: 0018:ffffc9000307e500 EFLAGS: 00000293 RAX: ffffffff8174b234 RBX: 1ffff110171c8541 RCX: ffff88801a59d940 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000307e640 R08: ffffffff8174b204 R09: ffffed10171c7679 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000 R13: ffff8880b8e42a08 R14: ffff8880b8f3b380 R15: 0000000000000001 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135 __flush_tlb_multi arch/x86/include/asm/paravirt.h:87 [inline] flush_tlb_multi arch/x86/mm/tlb.c:900 [inline] flush_tlb_mm_range+0x2a5/0x4a0 arch/x86/mm/tlb.c:986 flush_tlb_page arch/x86/include/asm/tlbflush.h:239 [inline] ptep_clear_flush+0x112/0x150 mm/pgtable-generic.c:97 page_mkclean_one+0x428/0x7b0 mm/rmap.c:938 rmap_walk_file+0x3f8/0x600 mm/rmap.c:2378 rmap_walk mm/rmap.c:2396 [inline] page_mkclean+0x330/0x490 mm/rmap.c:1006 clear_page_dirty_for_io+0x3ce/0xa60 mm/page-writeback.c:2749 mpage_submit_page+0x90/0x230 fs/ext4/inode.c:2092 mpage_process_page_bufs+0x6c8/0x8b0 fs/ext4/inode.c:2226 mpage_prepare_extent_to_map+0xc9d/0x1150 fs/ext4/inode.c:2654 ext4_writepages+0xcd0/0x3d10 fs/ext4/inode.c:2782 do_writepages+0x481/0x730 mm/page-writeback.c:2386 __writeback_single_inode+0x15b/0xe30 fs/fs-writeback.c:1647 writeback_sb_inodes+0xbce/0x1a40 fs/fs-writeback.c:1930 __writeback_inodes_wb+0x114/0x400 fs/fs-writeback.c:2001 wb_writeback+0x465/0xc50 fs/fs-writeback.c:2106 wb_check_old_data_flush fs/fs-writeback.c:2206 [inline] wb_do_writeback fs/fs-writeback.c:2259 [inline] wb_workfn+0xc55/0x1130 fs/fs-writeback.c:2288 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287