rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=6364/1/0x4000000000000000 softirq=44698/44699 fqs=1 rcu: (detected by 0, t=10505 jiffies, g=43841, q=222 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 13764 Comm: syz.3.2688 Not tainted 6.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:mark_lock+0x17/0xc60 kernel/locking/lockdep.c:4712 Code: ff 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41 56 41 89 d6 48 ba 00 00 00 00 00 fc ff df 41 55 <41> 54 53 48 83 e4 f0 48 81 ec 10 01 00 00 48 c7 44 24 30 b3 8a b5 RSP: 0018:ffffc90000a28b10 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffff888058e0afca RCX: ffff888058e0af80 RDX: dffffc0000000000 RSI: ffff888058e0afa8 RDI: ffff888058e0a440 RBP: ffffc90000a28b28 R08: 0000000000000003 R09: 0000000000000001 R10: ffffffff96ec6e7f R11: 0000000000000004 R12: ffff888058e0afa1 R13: ffff888058e0a440 R14: 0000000000000000 R15: ffff888058e0afa8 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff1cab61f98 CR3: 0000000024d04000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <NMI> </NMI> <IRQ> mark_usage kernel/locking/lockdep.c:4637 [inline] __lock_acquire+0x1390/0x3c40 kernel/locking/lockdep.c:5182 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] advance_sched+0xd8/0xc60 net/sched/sch_taprio.c:924 __run_hrtimer kernel/time/hrtimer.c:1801 [inline] __hrtimer_run_queues+0x20a/0xae0 kernel/time/hrtimer.c:1865 hrtimer_interrupt+0x392/0x8e0 kernel/time/hrtimer.c:1927 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x10f/0x400 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1049 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:check_kcov_mode kernel/kcov.c:185 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x3b/0x70 kernel/kcov.c:217 Code: 49 7e a9 00 01 ff 00 48 8b 34 24 74 1d f6 c4 01 74 43 a9 00 00 0f 00 75 3c a9 00 00 f0 00 75 35 8b 82 2c 16 00 00 85 c0 74 2b <8b> 82 08 16 00 00 83 f8 02 75 20 48 8b 8a 10 16 00 00 8b 92 0c 16 RSP: 0018:ffffc9000427f540 EFLAGS: 00000246 RAX: 0000000080000001 RBX: 0000000000000000 RCX: ffffffff8203e8af RDX: ffff888058e0a440 RSI: ffffffff81f3ba9e RDI: ffffea0001e1ac00 RBP: ffffea0001e1ac00 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000003 R12: 0000000000000000 R13: dffffc0000000000 R14: ffff888034d58d90 R15: dffffc0000000000 const_folio_flags+0xe/0x100 include/linux/page-flags.h:308 folio_test_dropbehind include/linux/page-flags.h:566 [inline] folio_mark_accessed+0x80/0xc00 mm/swap.c:451 zap_present_folio_ptes mm/memory.c:1519 [inline] zap_present_ptes mm/memory.c:1595 [inline] do_zap_pte_range mm/memory.c:1697 [inline] zap_pte_range mm/memory.c:1741 [inline] zap_pmd_range mm/memory.c:1833 [inline] zap_pud_range mm/memory.c:1862 [inline] zap_p4d_range mm/memory.c:1883 [inline] unmap_page_range+0x1413/0x4390 mm/memory.c:1904 unmap_single_vma+0x194/0x2b0 mm/memory.c:1950 unmap_vmas+0x22f/0x490 mm/memory.c:1994 exit_mmap+0x1c1/0xba0 mm/mmap.c:1284 __mmput+0x12a/0x410 kernel/fork.c:1356 mmput+0x62/0x70 kernel/fork.c:1378 exit_mm kernel/exit.c:570 [inline] do_exit+0x9ba/0x2db0 kernel/exit.c:925 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087 get_signal+0x24ed/0x26c0 kernel/signal.c:3036 arch_do_signal_or_restart+0x90/0x7e0 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+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff1c9d8d169 Code: Unable to access opcode bytes at 0x7ff1c9d8d13f. RSP: 002b:00007ff1cab620e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007ff1c9fa5fa8 RCX: 00007ff1c9d8d169 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff1c9fa5fa8 RBP: 00007ff1c9fa5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff1c9fa5fac R13: 0000000000000000 R14: 00007ffe5eb52270 R15: 00007ffe5eb52358 </TASK> rcu: rcu_preempt kthread starved for 10500 jiffies! g43841 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:28248 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: <TASK> context_switch kernel/sched/core.c:5378 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6857 schedule_timeout+0x124/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2024 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2226 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 </TASK> rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 5828 Comm: syz-executor Not tainted 6.14.0-syzkaller #0 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+0x4cb/0x12c0 kernel/smp.c:885 Code: 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 fc 4c 89 fd 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 ac 0e 0c 00 f3 90 41 0f b6 04 24 <40> 38 c5 7c 08 84 c0 0f 85 e8 0b 00 00 8b 43 08 31 ff 83 e0 01 41 RSP: 0018:ffffc9000421f8f8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b8744a80 RCX: ffffffff81ade1ea RDX: ffff888025e62440 RSI: ffffffff81ade1c4 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffed10170e8951 R13: 0000000000000001 R14: ffff8880b863fe80 R15: ffff8880b8744a88 FS: 0000555576328500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0efdcd56c0 CR3: 0000000063aae000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> </IRQ> <TASK> on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:966 [inline] flush_tlb_mm_range+0x271/0x4a0 arch/x86/mm/tlb.c:1054 dup_mmap kernel/fork.c:787 [inline] dup_mm kernel/fork.c:1700 [inline] copy_mm kernel/fork.c:1752 [inline] copy_process+0x70fb/0x8c50 kernel/fork.c:2403 kernel_clone+0xfd/0x960 kernel/fork.c:2815 __do_sys_clone+0xcf/0x120 kernel/fork.c:2958 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0efcf839d3 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffc7a93a388 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0efcf839d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 00005555763287d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 000000000007f040 R15: 00007ffc7a93a520 </TASK>