rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (53 ticks this GP) idle=145/1/0x4000000000000000 softirq=21600/21604 fqs=767 (detected by 1, t=10502 jiffies, g=26157, q=733) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9264 Comm: syz.5.1306 Not tainted 5.15.178-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:29 [inline] RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:28 [inline] RIP: 0010:queued_spin_is_locked include/asm-generic/qspinlock.h:28 [inline] RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:100 [inline] RIP: 0010:do_raw_spin_unlock+0x5f/0x8b0 kernel/locking/spinlock_debug.c:140 Code: 0f 85 2e 04 00 00 81 3a ad 4e ad de 0f 85 01 01 00 00 4c 89 ff be 04 00 00 00 e8 8c 27 66 00 4c 89 f8 48 c1 e8 03 0f b6 04 18 <84> c0 0f 85 24 04 00 00 41 83 3f 00 0f 84 9a 01 00 00 4d 8d 6f 10 RSP: 0018:ffffc90000007c50 EFLAGS: 00000802 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffffffff816447f4 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff888079c77ae8 RBP: ffff888079c77ae8 R08: dffffc0000000000 R09: ffffed100f38ef5e R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888079c77800 R13: ffff888079c77b40 R14: dffffc0000000000 R15: ffff888079c77ae8 FS: 00007f02e9e146c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30716ff8 CR3: 0000000053601000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock+0x1a/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:403 [inline] advance_sched+0x68b/0x940 net/sched/sch_taprio.c:765 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x598/0xcf0 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 3c 12 09 00 48 83 c4 08 4c 89 ff e8 90 db fe ff 66 90 4c 89 ff e8 b6 31 ef 08 e8 f1 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:ffffc9000309f298 EFLAGS: 00000286 RAX: 6cd27dea0888e200 RBX: ffff88802a255974 RCX: ffffffff96a92f03 RDX: dffffc0000000000 RSI: ffffffff8aab2b80 RDI: ffffffff8af9f2c0 RBP: ffffc9000309f310 R08: ffffffff81870420 R09: ffffed10171c7461 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 schedule+0x11b/0x1f0 kernel/sched/core.c:6456 schedule_timeout+0xac/0x300 kernel/time/timer.c:1890 unix_wait_for_peer+0x24b/0x330 net/unix/af_unix.c:1304 unix_dgram_sendmsg+0x1441/0x2090 net/unix/af_unix.c:1899 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2436 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2490 __sys_sendmmsg+0x2bf/0x560 net/socket.c:2576 __do_sys_sendmmsg net/socket.c:2605 [inline] __se_sys_sendmmsg net/socket.c:2602 [inline] __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2602 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: 0033:0x7f02ebfaade9 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:00007f02e9e14038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f02ec1c3fa0 RCX: 00007f02ebfaade9 RDX: 0000000000000651 RSI: 0000400000000000 RDI: 0000000000000004 RBP: 00007f02ec02c2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f02ec1c3fa0 R15: 00007ffe4d148c68 rcu: rcu_preempt kthread starved for 8752 jiffies! g26157 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:27256 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: 4304 Comm: kworker/u4:10 Not tainted 5.15.178-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 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: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+0xaa1/0xd90 kernel/smp.c:969 Code: 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 01 00 00 00 74 1e e8 ac d2 0b 00 eb db 44 RSP: 0018:ffffc9000318e500 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff110171c8541 RCX: ffff8880247f8000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000318e640 R08: ffffffff8174b2b4 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