rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (34 ticks this GP) idle=ee7/1/0x4000000000000000 softirq=50808/50811 fqs=413 (detected by 0, t=10506 jiffies, g=67421, q=341) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 12730 Comm: syz.0.1942 Not tainted 5.15.164-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 RIP: 0010:__hrtimer_run_queues+0x671/0xcf0 kernel/time/hrtimer.c:1750 Code: b5 f6 10 00 49 bf 00 00 00 00 00 fc ff df 48 8b 5c 24 10 4c 89 e7 e8 3e 37 cd 08 31 ff 44 89 ee e8 f4 f9 10 00 45 85 ed 74 47 <48> 8b 84 24 b0 00 00 00 42 0f b6 04 38 84 c0 4c 8b 6c 24 38 48 8b RSP: 0018:ffffc90000dd0d60 EFLAGS: 00000002 RAX: 0000000080010002 RBX: ffff8880b9b2a348 RCX: 0000000000000001 RDX: ffff888022cd8000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000dd0eb0 R08: ffffffff816f6acc R09: 0000000000000003 R10: ffffffffffffffff R11: dffffc0000000001 R12: ffff8880b9b2a200 R13: 0000000000000001 R14: ffff888067f74b40 R15: dffffc0000000000 FS: 00007fb3a2e946c0(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb39aa5a000 CR3: 0000000014bb3000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline] __sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xd4/0x130 kernel/locking/spinlock.c:194 Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 f2 90 8d f7 f6 44 24 21 02 75 4e 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 97 c6 1a f7 65 8b 05 58 cb c5 75 85 c0 74 3f 48 c7 04 24 0e 36 RSP: 0018:ffffc900033a75a0 EFLAGS: 00000206 RAX: 181cf78c76082300 RBX: 1ffff92000674eb8 RCX: ffffffff816319d8 RDX: dffffc0000000000 RSI: ffffffff8a8b2a00 RDI: 0000000000000001 RBP: ffffc900033a7630 R08: dffffc0000000000 R09: fffffbfff1f8e02e R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000 R13: 1ffff92000674eb4 R14: ffffc900033a75c0 R15: 0000000000000246 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:2338 ____sys_recvmsg+0x286/0x530 ___sys_recvmsg+0x1ec/0x690 net/socket.c:2692 do_recvmmsg+0x36f/0x8f0 net/socket.c:2786 __sys_recvmmsg net/socket.c:2865 [inline] __do_sys_recvmmsg net/socket.c:2888 [inline] __se_sys_recvmmsg net/socket.c:2881 [inline] __x64_sys_recvmmsg+0x195/0x240 net/socket.c:2881 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: 0033:0x7fb3a4a369f9 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:00007fb3a2e94038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007fb3a4bc5058 RCX: 00007fb3a4a369f9 RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 00007fb3a4aa48ee R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fb3a4bc5058 R15: 00007ffe7565ea88 rcu: rcu_preempt kthread starved for 8490 jiffies! g67421 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:26144 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376 schedule+0x11b/0x1f0 kernel/sched/core.c:6459 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 0 CPU: 0 PID: 7097 Comm: kworker/u4:14 Not tainted 5.15.164-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 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:1686 [inline] __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1750 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline] __sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 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 7c cf 0b 00 41 83 e7 01 75 07 e8 11 cc 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:ffffc90002de6500 EFLAGS: 00000293 RAX: ffffffff81749574 RBX: 1ffff110173680b9 RCX: ffff8880522e0000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90002de6640 R08: ffffffff81749544 R09: ffffed1017367681 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000001 R13: ffff8880b9b405c8 R14: ffff8880b9a3b3c0 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:2081 mpage_process_page_bufs+0x6c8/0x8b0 fs/ext4/inode.c:2215 mpage_prepare_extent_to_map+0xc9d/0x1150 fs/ext4/inode.c:2643 ext4_writepages+0xcd0/0x3d10 fs/ext4/inode.c:2771 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