rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=6445, q=118) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294953841-4294943338), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.0 R running task 27912 8238 8215 0x0000400a Call Trace: sched_show_task+0x40f/0x560 kernel/sched/core.c:5954 print_other_cpu_stall kernel/rcu/tree_stall.h:410 [inline] check_cpu_stall kernel/rcu/tree_stall.h:538 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq+0x1861/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:__sanitizer_cov_trace_pc+0x48/0x50 kernel/kcov.c:112 Code: 80 13 00 00 83 fa 02 75 21 48 8b 91 88 13 00 00 48 8b 32 48 8d 7e 01 8b 89 84 13 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 3a 0f 1f 80 00 00 00 00 4c 8b 04 24 65 48 8b 04 25 c0 1d 02 00 65 RSP: 0018:ffffc900021779b0 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81487433 RBX: 0000000000000000 RCX: ffff8880a51e21c0 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea0001b0e6c0 RBP: ffffc900021779d8 R08: 000000000003a768 R09: ffffed1013d5a72f R10: ffffed1013d5a72f R11: 0000000000000000 R12: dffffc0000000000 R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff88809ead3968 free_thread_stack+0x168/0x590 kernel/fork.c:280 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 preempt_schedule_common kernel/sched/core.c:4236 [inline] preempt_schedule+0xdb/0x120 kernel/sched/core.c:4261 ___preempt_schedule+0x16/0x18 arch/x86/entry/thunk_64.S:50 try_to_wake_up+0xe78/0x1050 kernel/sched/core.c:2650 wake_up_process+0x10/0x20 kernel/sched/core.c:2668 kthread_stop+0xf5/0x210 kernel/kthread.c:558 destroy_workqueue+0xfa/0xe30 kernel/workqueue.c:4364 ucma_close+0x2a4/0x2c0 drivers/infiniband/core/ucma.c:1771 __fput+0x2e4/0x740 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x17e/0x1b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop arch/x86/entry/common.c:164 [inline] prepare_exit_to_usermode+0x483/0x5b0 arch/x86/entry/common.c:195 syscall_return_slowpath+0x113/0x4a0 arch/x86/entry/common.c:278 do_syscall_64+0x11f/0x1c0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x414211 Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 1b 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007ffd7f3118b0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000414211 RDX: 0000001b2d220000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00000000662245ed R09: 00000000662245f1 R10: 00007ffd7f311990 R11: 0000000000000293 R12: 000000000075c9a0 R13: 000000000075c9a0 R14: 0000000000760828 R15: 000000000075bfd4 rcu: rcu_preempt kthread starved for 10537 jiffies! g6445 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29032 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352