rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=065c/1/0x4000000000000000 softirq=30123/30124 fqs=1 rcu: (detected by 0, t=10511 jiffies, g=28469, q=968 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 7753 Comm: syz.5.365 Not tainted 6.14.0-syzkaller-13305-g61f96e684edd #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data kernel/kcov.c:246 [inline] RIP: 0010:__sanitizer_cov_trace_switch+0xa4/0x120 kernel/kcov.c:351 Code: 8b 00 00 00 4c 8b 4c 24 20 65 4c 8b 1c 25 08 a0 68 93 31 d2 eb 08 48 ff c2 49 39 d2 74 71 4c 8b 74 d6 10 65 8b 05 cc 42 a5 11 <25> 00 01 ff 00 74 11 3d 00 01 00 00 75 de 41 83 bb 3c 16 00 00 00 RSP: 0018:ffffc90000a08390 EFLAGS: 00000012 RAX: 0000000080010007 RBX: 0000000000000004 RCX: dffffc0000000000 RDX: 000000000000000a RSI: ffffffff8ed93030 RDI: 0000000000000004 RBP: 00000000000000a2 R08: 0000000000000005 R09: ffffffff81c76d53 R10: 0000000000000020 R11: ffff88802f055a00 R12: 000000592bc77e7b R13: 0000000000000ca8 R14: 000000000000000a R15: ffff88801dab1cb8 FS: 0000000000000000(0000) GS:ffff888125096000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007faf74c6ef98 CR3: 000000006642c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rb_read_data_buffer+0x103/0x520 kernel/trace/ring_buffer.c:1820 check_buffer+0x3b1/0x8f0 kernel/trace/ring_buffer.c:4297 __rb_reserve_next kernel/trace/ring_buffer.c:4396 [inline] rb_reserve_next_event kernel/trace/ring_buffer.c:4533 [inline] ring_buffer_lock_reserve+0x12b1/0x21d0 kernel/trace/ring_buffer.c:4592 __trace_buffer_lock_reserve kernel/trace/trace.c:1028 [inline] trace_event_buffer_lock_reserve+0x2ab/0x6a0 kernel/trace/trace.c:2742 trace_event_buffer_reserve+0x2fe/0x450 kernel/trace/trace_events.c:661 do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline] trace_event_raw_event_bpf_trace_printk+0x104/0x270 kernel/trace/bpf_trace.h:11 __do_trace_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline] trace_bpf_trace_printk+0x186/0x1f0 kernel/trace/bpf_trace.h:11 ____bpf_trace_printk kernel/trace/bpf_trace.c:380 [inline] bpf_trace_printk+0x1c1/0x230 kernel/trace/bpf_trace.c:363 bpf_prog_0605f9f479290f07+0x38/0x3c bpf_dispatcher_nop_func include/linux/bpf.h:1316 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2363 [inline] bpf_trace_run2+0x2ee/0x550 kernel/trace/bpf_trace.c:2404 __bpf_trace_hrtimer_start+0x177/0x240 include/trace/events/timer.h:222 __do_trace_hrtimer_start include/trace/events/timer.h:222 [inline] trace_hrtimer_start include/trace/events/timer.h:222 [inline] debug_activate kernel/time/hrtimer.c:487 [inline] enqueue_hrtimer+0x352/0x3c0 kernel/time/hrtimer.c:1090 __run_hrtimer kernel/time/hrtimer.c:1808 [inline] __hrtimer_run_queues+0x6d6/0xd40 kernel/time/hrtimer.c:1855 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1917 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x167/0x2f0 arch/x86/include/asm/irqflags.h:-1 Code: c7 44 24 10 00 00 00 00 9c 8f 44 24 10 f7 44 24 10 00 02 00 00 0f 85 fd 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 65 48 8b 45 00 <48> 3b 44 24 38 0f 85 72 01 00 00 48 83 c4 40 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90004f87110 EFLAGS: 00000206 RAX: 6b255cea6c5afb00 RBX: ffffffff8ed3df60 RCX: 6b255cea6c5afb00 RDX: 0000000000000000 RSI: ffffffff8e4fce8a RDI: ffffffff8ca1b120 RBP: ffffffff9368a020 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000002 R14: 0000000000000246 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock_sched include/linux/rcupdate.h:932 [inline] pfn_valid+0x113/0x450 include/linux/mmzone.h:2116 page_table_check_clear+0x21/0x6f0 mm/page_table_check.c:70 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline] clear_full_ptes include/linux/pgtable.h:751 [inline] zap_present_folio_ptes mm/memory.c:1514 [inline] zap_present_ptes mm/memory.c:1586 [inline] do_zap_pte_range mm/memory.c:1687 [inline] zap_pte_range mm/memory.c:1731 [inline] zap_pmd_range mm/memory.c:1823 [inline] zap_pud_range mm/memory.c:1852 [inline] zap_p4d_range mm/memory.c:1873 [inline] unmap_page_range+0x33f4/0x44d0 mm/memory.c:1894 unmap_vmas+0x3ce/0x5f0 mm/memory.c:1984 exit_mmap+0x2bc/0xde0 mm/mmap.c:1284 __mmput+0x115/0x420 kernel/fork.c:1379 exit_mm+0x221/0x310 kernel/exit.c:589 do_exit+0x994/0x27f0 kernel/exit.c:940 do_group_exit+0x207/0x2c0 kernel/exit.c:1102 get_signal+0x1696/0x1730 kernel/signal.c:3034 arch_do_signal_or_restart+0x98/0x840 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb25df8d169 Code: Unable to access opcode bytes at 0x7fb25df8d13f. RSP: 002b:00007ffd67c4b548 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffff92 RBX: 0000000000039c30 RCX: 00007fb25df8d169 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fb25e1a608c RBP: 0000000000000032 R08: 7fffffffffffffff R09: 0000000867c4b83f R10: 00007ffd67c4b640 R11: 0000000000000246 R12: 00007fb25e1a608c R13: 00007ffd67c4b640 R14: 0000000000039c62 R15: 00007ffd67c4b660 rcu: rcu_preempt kthread starved for 10410 jiffies! g28469 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:26216 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 5833 Comm: syz-executor Not tainted 6.14.0-syzkaller-13305-g61f96e684edd #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0x1bac/0x2d40 kernel/smp.c:885 Code: 03 84 c0 75 7e 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 c8 e2 0b 00 41 83 e4 01 4c 8b 64 24 68 75 07 e8 78 de 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:ffffc90003f6f380 EFLAGS: 00000293 RAX: ffffffff81b778ed RBX: 1ffff110170e7e91 RCX: ffff88803204da00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003f6f580 R08: ffffffff81b778b8 R09: 1ffffffff20bface R10: dffffc0000000000 R11: fffffbfff20bfacf R12: ffff8880b863ad08 R13: ffff8880b873f488 R14: ffff8880b863ad00 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888124f96000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007faf74c0c9a0 CR3: 0000000055f58000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1275 [inline] flush_tlb_mm_range+0xb8d/0x13f0 arch/x86/mm/tlb.c:1365 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline] tlb_flush_mmu+0x1aa/0x690 mm/mmu_gather.c:403 tlb_finish_mmu+0xd4/0x200 mm/mmu_gather.c:496 exit_mmap+0x5b1/0xde0 mm/mmap.c:1297 __mmput+0x115/0x420 kernel/fork.c:1379 exit_mm+0x221/0x310 kernel/exit.c:589 do_exit+0x994/0x27f0 kernel/exit.c:940 do_group_exit+0x207/0x2c0 kernel/exit.c:1102 get_signal+0x1696/0x1730 kernel/signal.c:3034 arch_do_signal_or_restart+0x98/0x840 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f371a583393 Code: Unable to access opcode bytes at 0x7f371a583369. RSP: 002b:00007fffbe6d2e08 EFLAGS: 00000202 ORIG_RAX: 000000000000003d RAX: fffffffffffffe00 RBX: 00000000000016d3 RCX: 00007f371a583393 RDX: 0000000040000000 RSI: 00007fffbe6d2e1c RDI: 00000000ffffffff RBP: 00007fffbe6d2e1c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008 R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000