rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (6 ticks this GP) idle=3c5c/1/0x4000000000000000 softirq=23412/23414 fqs=0 rcu: (detected by 1, t=10506 jiffies, g=30685, q=123 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 8886 Comm: syz.4.1120 Not tainted 6.11.0-rc1-syzkaller-00293-gdefaf1a2113a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 RIP: 0010:check_kcov_mode kernel/kcov.c:173 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x18/0x70 kernel/kcov.c:207 Code: 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 00 d7 03 00 65 8b 15 20 61 70 7e c2 00 01 ff 00 74 11 f7 c2 00 01 00 00 74 35 83 b9 1c 16 00 00 RSP: 0018:ffffc90000007c28 EFLAGS: 00000002 RAX: ffffffff89b41d44 RBX: ffff8880226bd000 RCX: ffff88801fde1e00 RDX: 0000000080010004 RSI: 0000000000000004 RDI: ffff8880226bd080 RBP: 0000000000000000 R08: ffff8880226bd083 R09: 1ffff110044d7a10 R10: dffffc0000000000 R11: ffffed10044d7a11 R12: 0000000000000000 R13: ffff8880226bd000 R14: ffff8880226bd080 R15: 0000000000000000 FS: 00007f370d95d6c0(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020041000 CR3: 00000000500b8000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: taprio_set_budgets+0x244/0x370 net/sched/sch_taprio.c:664 advance_sched+0x98d/0xca0 net/sched/sch_taprio.c:977 __run_hrtimer kernel/time/hrtimer.c:1689 [inline] __hrtimer_run_queues+0x59b/0xd50 kernel/time/hrtimer.c:1753 hrtimer_interrupt+0x396/0x990 kernel/time/hrtimer.c:1815 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline] __sysvec_apic_timer_interrupt+0x110/0x3f0 arch/x86/kernel/apic/apic.c:1049 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1043 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 3e 5f 40 f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 83 c5 ab f5 65 8b 05 d4 ac 4c 74 85 c0 74 43 48 c7 04 24 0e 36 RSP: 0018:ffffc900091d72a0 EFLAGS: 00000206 RAX: 8e4725dcec854200 RBX: 1ffff9200123ae58 RCX: ffffffff81702daa RDX: dffffc0000000000 RSI: ffffffff8bead560 RDI: 0000000000000001 RBP: ffffc900091d7330 R08: ffffffff934ec85f R09: 1ffffffff269d90b R10: dffffc0000000000 R11: fffffbfff269d90c R12: dffffc0000000000 R13: 1ffff9200123ae54 R14: ffffc900091d72c0 R15: 0000000000000246 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] unlock_page_lruvec_irqrestore include/linux/memcontrol.h:1524 [inline] folio_lruvec_relock_irqsave include/linux/memcontrol.h:1557 [inline] folio_batch_move_lru+0x240/0x4e0 mm/swap.c:214 folio_add_lru+0x39c/0x9e0 mm/swap.c:526 do_anonymous_page mm/memory.c:4604 [inline] do_pte_missing mm/memory.c:3945 [inline] handle_pte_fault+0x4ee8/0x6eb0 mm/memory.c:5522 __handle_mm_fault mm/memory.c:5665 [inline] handle_mm_fault+0xf70/0x1880 mm/memory.c:5833 do_user_addr_fault arch/x86/mm/fault.c:1389 [inline] handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x2b9/0x8c0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:rep_movs_alternative+0x4a/0x70 arch/x86/lib/copy_user_64.S:71 Code: 75 f1 c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb c9 a4 c3 cc cc cc cc 48 89 c8 48 c1 e9 03 83 e0 07 f3 48 a5 89 c1 RSP: 0018:ffffc900091d7ad0 EFLAGS: 00050246 RAX: ffffffff84a7b301 RBX: 0000000020041040 RCX: 0000000000000040 RDX: 0000000000000000 RSI: ffffc900091d7b60 RDI: 0000000020041000 RBP: ffffc900091d7c10 R08: ffffc900091d7b9f R09: 1ffff9200123af73 R10: dffffc0000000000 R11: fffff5200123af74 R12: 0000000000000040 R13: 000000000000d580 R14: 0000000020041000 R15: ffffc900091d7b60 copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline] raw_copy_to_user arch/x86/include/asm/uaccess_64.h:131 [inline] _inline_copy_to_user include/linux/uaccess.h:181 [inline] _copy_to_user+0x86/0xb0 lib/usercopy.c:26 copy_to_user include/linux/uaccess.h:209 [inline] rng_dev_read+0x3be/0x6d0 drivers/char/hw_random/core.c:251 do_loop_readv_writev fs/read_write.c:761 [inline] vfs_readv+0x6c2/0xa90 fs/read_write.c:934 do_preadv fs/read_write.c:1049 [inline] __do_sys_preadv fs/read_write.c:1099 [inline] __se_sys_preadv fs/read_write.c:1094 [inline] __x64_sys_preadv+0x1c7/0x2d0 fs/read_write.c:1094 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: 0033:0x7f370cb779f9 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:00007f370d95d048 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007f370cd05f80 RCX: 00007f370cb779f9 RDX: 0000000000000001 RSI: 0000000020000240 RDI: 0000000000000004 RBP: 00007f370cbe58ee R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f370cd05f80 R15: 00007ffe4d1efbe8 rcu: rcu_preempt kthread starved for 10506 jiffies! g30685 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:25168 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x17ae/0x4a10 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6621 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2034 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2236 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: 8882 Comm: syz.4.1120 Not tainted 6.11.0-rc1-syzkaller-00293-gdefaf1a2113a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline] RIP: 0010:kvm_wait+0x250/0x2c0 arch/x86/kernel/kvm.c:1060 Code: 3b 45 0f b6 f6 44 89 ff 44 89 f6 e8 2a 0f 53 00 e8 35 73 5a 00 45 38 f7 75 15 66 90 e8 99 0e 53 00 0f 00 2d 82 ca a7 0a fb f4 50 fe ff ff e8 86 0e 53 00 fb e9 45 fe ff ff 89 d9 80 e1 07 38 RSP: 0000:ffffc9000309f580 EFLAGS: 000002d3 RAX: ffffffff81406737 RBX: ffff88801f687ea0 RCX: ffff888029db9e00 RDX: 0000000000000000 RSI: ffffffff8bead560 RDI: ffffffff8c3f8900 RBP: ffffc9000309f650 R08: ffffffff934ec807 R09: 1ffffffff269d900 R10: dffffc0000000000 R11: fffffbfff269d901 R12: 1ffff92000613eb4 R13: dffffc0000000000 R14: 0000000000000003 R15: 0000000000000003 FS: 0000555593fac500(0000) GS:ffff8880b9300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020002ec4 CR3: 00000000500b8000 CR4: 00000000003526f0 Call Trace: pv_wait arch/x86/include/asm/paravirt.h:596 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:466 [inline] __pv_queued_spin_lock_slowpath+0x8d0/0xdc0 kernel/locking/qspinlock.c:508 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline] queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x272/0x370 kernel/locking/spinlock_debug.c:116 spin_lock include/linux/spinlock.h:351 [inline] __pte_offset_map_lock+0x1ba/0x300 mm/pgtable-generic.c:375 pte_offset_map_lock include/linux/mm.h:2985 [inline] do_anonymous_page mm/memory.c:4576 [inline] do_pte_missing mm/memory.c:3945 [inline] handle_pte_fault+0x47e7/0x6eb0 mm/memory.c:5522 __handle_mm_fault mm/memory.c:5665 [inline] handle_mm_fault+0xf70/0x1880 mm/memory.c:5833 do_user_addr_fault arch/x86/mm/fault.c:1338 [inline] handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x459/0x8c0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7f370ca3ef91 Code: 48 8b 54 24 08 48 85 d2 74 17 8b 44 24 18 0f c8 89 c0 48 89 44 24 18 48 83 fa 01 0f 85 b3 01 00 00 48 8b 44 24 10 8b 54 24 18 <89> 10 e9 15 fd ff ff 48 8b 44 24 10 8b 10 48 8b 44 24 08 48 85 c0 RSP: 002b:00007ffe4d1efd10 EFLAGS: 00010246 RAX: 0000000020002ec4 RBX: 0000000000000004 RCX: 0000000000000000 RDX: 000000000000ccfa RSI: 0000000000000000 RDI: 0000555593fac3c8 RBP: 00007ffe4d1efe20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000002 R12: 0000000000000032 R13: 00007ffe4d1efe40 R14: 00007ffe4d1efe60 R15: fffffffffffffffe