rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=41e4/1/0x4000000000000000 softirq=32432/32432 fqs=5 rcu: (detected by 0, t=10506 jiffies, g=25789, q=239 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 8850 Comm: syz.3.746 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:mark_lock+0xab/0x610 kernel/locking/lockdep.c:4722 Code: 48 8b 54 24 68 65 48 2b 15 0a 93 08 12 0f 85 e8 04 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 89 7a ca 09 f6 46 22 03 <74> 8d 41 bd 00 02 00 00 bb 09 00 00 00 eb 8e 44 8b 1d 8f 03 18 19 RSP: 0018:ffffc90000a08b50 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000000 RDX: 0000000000000008 RSI: ffff888028590bd0 RDI: ffff888028590000 RBP: ffffc90000a08be8 R08: 0000000000000001 R09: 0000000000000001 R10: 00000000000000a0 R11: 0000000000000001 R12: ffff888028590bd0 R13: ffff888028590bd0 R14: 0000000000000004 R15: ffff888028590000 FS: 00007f7622f5f6c0(0000) GS:ffff888124b0b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7622f5ef98 CR3: 0000000028dc1000 CR4: 00000000003526f0 Call Trace: mark_usage kernel/locking/lockdep.c:4674 [inline] __lock_acquire+0x3e9/0x1c90 kernel/locking/lockdep.c:5191 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 debug_object_deactivate+0x135/0x3a0 lib/debugobjects.c:873 debug_hrtimer_deactivate kernel/time/hrtimer.c:443 [inline] debug_deactivate kernel/time/hrtimer.c:483 [inline] __run_hrtimer kernel/time/hrtimer.c:1745 [inline] __hrtimer_run_queues+0x46f/0xad0 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:write_comp_data+0x42/0x90 kernel/kcov.c:246 Code: a9 00 01 ff 00 74 1d f6 c4 01 74 67 a9 00 00 0f 00 75 60 a9 00 00 f0 00 75 59 8b 82 7c 16 00 00 85 c0 74 4f 8b 82 58 16 00 00 <83> f8 03 75 44 48 8b 82 60 16 00 00 8b 92 5c 16 00 00 48 8b 38 48 RSP: 0018:ffffc9000ba6f358 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffea00004a1580 RCX: ffffffff821b1366 RDX: ffff888028590000 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 0000000000000000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff8880553a62e8 R13: 000000000000001e R14: 000020000005d000 R15: dffffc0000000000 folio_flags.constprop.0+0x36/0x70 include/linux/page-flags.h:360 folio_clear_referenced include/linux/page-flags.h:553 [inline] madvise_cold_or_pageout_pte_range+0xb45/0x20d0 mm/madvise.c:545 walk_pmd_range mm/pagewalk.c:130 [inline] walk_pud_range mm/pagewalk.c:224 [inline] walk_p4d_range mm/pagewalk.c:262 [inline] walk_pgd_range+0xc05/0x1f50 mm/pagewalk.c:303 __walk_page_range+0x163/0x820 mm/pagewalk.c:410 walk_page_range_vma+0x2c7/0xa20 mm/pagewalk.c:717 madvise_pageout_page_range mm/madvise.c:624 [inline] madvise_pageout+0x257/0x540 mm/madvise.c:649 madvise_vma_behavior+0xb14/0x2d50 mm/madvise.c:1352 madvise_walk_vmas+0x31f/0x9c0 mm/madvise.c:1669 madvise_do_behavior+0x1e2/0x530 mm/madvise.c:1885 do_madvise+0x176/0x240 mm/madvise.c:1978 __do_sys_madvise mm/madvise.c:1987 [inline] __se_sys_madvise mm/madvise.c:1985 [inline] __x64_sys_madvise+0xa9/0x110 mm/madvise.c:1985 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f762218efc9 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:00007f7622f5f038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f76223e6090 RCX: 00007f762218efc9 RDX: 0000000000000015 RSI: 0000000000600000 RDI: 0000200000000000 RBP: 00007f7622211f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f76223e6128 R14: 00007f76223e6090 R15: 00007fffabc1dfe8 rcu: rcu_preempt kthread starved for 10480 jiffies! g25789 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:27704 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7026 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158 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: 8835 Comm: syz.1.741 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x17/0x70 kernel/kcov.c:217 Code: 02 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 34 24 65 48 8b 15 b8 45 e4 11 65 8b 05 c9 45 e4 11 00 01 ff 00 74 1d f6 c4 01 74 43 a9 00 00 0f 00 75 3c a9 00 00 RSP: 0018:ffffc90004aef6f0 EFLAGS: 00000202 RAX: 0000000000000002 RBX: ffff8880b8540320 RCX: ffffffff81b0fd91 RDX: ffff888026628000 RSI: ffffffff81b0fd6b RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000 R13: ffffed10170a8065 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888124a0b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2f863fff CR3: 0000000077a43000 CR4: 00000000003526f0 Call Trace: native_pause arch/x86/include/asm/vdso/processor.h:13 [inline] cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0xdfb/0x1600 kernel/smp.c:877 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1043 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1381 [inline] flush_tlb_mm_range+0x4a0/0x17a0 arch/x86/mm/tlb.c:1471 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline] tlb_flush_mmu mm/mmu_gather.c:403 [inline] tlb_finish_mmu+0x3c9/0x7c0 mm/mmu_gather.c:497 exit_mmap+0x3fc/0xb90 mm/mmap.c:1293 __mmput+0x12a/0x410 kernel/fork.c:1133 mmput+0x62/0x70 kernel/fork.c:1156 exit_mm kernel/exit.c:582 [inline] do_exit+0x7c7/0x2bf0 kernel/exit.c:954 do_group_exit+0xd3/0x2a0 kernel/exit.c:1107 get_signal+0x2671/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7c0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x85/0x130 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f96cf18efc9 Code: Unable to access opcode bytes at 0x7f96cf18ef9f. RSP: 002b:00007f96cff710e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f96cf3e6098 RCX: 00007f96cf18efc9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f96cf3e6098 RBP: 00007f96cf3e6090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f96cf3e6128 R14: 00007ffe30ed4660 R15: 00007ffe30ed4748