rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=b6f4/1/0x4000000000000000 softirq=10797/10801 fqs=1 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3623/1:b..l (detected by 1, t=10505 jiffies, g=11693, q=175 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4725 Comm: syz.1.148 Not tainted 6.1.131-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:instrument_atomic_read include/linux/instrumented.h:72 [inline] RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:444 [inline] RIP: 0010:cpu_online include/linux/cpumask.h:1030 [inline] RIP: 0010:trace_lock_acquire include/trace/events/lock.h:24 [inline] RIP: 0010:lock_acquire+0xe6/0x5a0 kernel/locking/lockdep.c:5633 Code: 84 c0 0f 85 59 03 00 00 39 1d 4e 02 36 0d 0f 86 e4 02 00 00 89 db 48 89 d8 48 c1 e8 06 48 8d 3c c5 68 b4 a0 8e be 08 00 00 00 45 58 77 00 48 0f a3 1d 15 00 36 0d 73 0d e8 96 e1 08 00 84 c0 RSP: 0018:ffffc90000007b60 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ea0b468 RBP: ffffc90000007ca8 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000000f74 R13: dffffc0000000000 R14: 0000000000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3b29a2 CR3: 00000000579de000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0xcf/0x110 kernel/locking/spinlock.c:170 __run_hrtimer kernel/time/hrtimer.c:1693 [inline] __hrtimer_run_queues+0x6d3/0xe50 kernel/time/hrtimer.c:1753 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1815 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x158/0x5b0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:lock_is_held_type+0x144/0x180 kernel/locking/lockdep.c:5710 Code: 24 f7 04 24 00 02 00 00 75 46 41 f7 c4 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 48 3b 44 24 08 75 3c 89 e8 48 83 c4 10 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 0f 0b 48 c7 c7 40 1d 0c 8b e8 b3 RSP: 0018:ffffc9000610f278 EFLAGS: 00000286 RAX: 0000000000000001 RBX: 0000000000000002 RCX: 0000000080000001 RDX: 0000000000000000 RSI: ffffffff8b0c2ec0 RDI: ffffffff8b5f6f80 RBP: 0000000000000001 R08: ffffffff81eccaea R09: fffffbfff225724d R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000246 R13: ffff888019b7d940 R14: 00000000ffffffff R15: ffffffff8d32e6c0 lookup_page_ext mm/page_ext.c:277 [inline] page_ext_get+0x18e/0x2a0 mm/page_ext.c:158 page_table_check_clear+0x4b/0x6d0 mm/page_table_check.c:71 zap_pte_range mm/memory.c:1435 [inline] zap_pmd_range mm/memory.c:1574 [inline] zap_pud_range mm/memory.c:1603 [inline] zap_p4d_range mm/memory.c:1624 [inline] unmap_page_range+0x1b4a/0x2740 mm/memory.c:1645 unmap_vmas+0x48b/0x640 mm/memory.c:1730 exit_mmap+0x249/0x980 mm/mmap.c:3238 __mmput+0x115/0x3c0 kernel/fork.c:1200 exit_mm+0x226/0x300 kernel/exit.c:565 do_exit+0x9f1/0x26a0 kernel/exit.c:858 do_group_exit+0x202/0x2b0 kernel/exit.c:1021 get_signal+0x16cb/0x17a0 kernel/signal.c:2871 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fb18958d169 Code: Unable to access opcode bytes at 0x7fb18958d13f. RSP: 002b:00007fb18a3ff0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fb1897a5fa8 RCX: 00007fb18958d169 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fb1897a5fa8 RBP: 00007fb1897a5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb1897a5fac R13: 0000000000000000 R14: 00007ffd45d78f40 R15: 00007ffd45d79028 task:udevd state:R running task stack:24600 pid:3623 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5243 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6560 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6872 irqentry_exit+0x53/0x80 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:lock_acquire+0x1/0x5a0 kernel/locking/lockdep.c:5630 Code: fd ff ff 48 c7 c7 38 e9 a0 8e e8 aa 57 77 00 e9 a2 fd ff ff 0f 1f 44 00 00 65 8b 05 f1 bb 97 7e a9 00 ff ff 00 0f 95 c0 c3 55 <48> 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec 20 01 00 RSP: 0018:ffffc90003267748 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffff88802808eeb0 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8d32e6c0 RBP: ffffc900032678d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: dffffc0000000001 R12: ffffc90003267850 R13: ffffc90003267b00 R14: ffffffff81f71387 R15: ffff888075905be8 rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock include/linux/rcupdate.h:791 [inline] dput+0x54/0x1d0 fs/dcache.c:904 step_into+0x351/0x1070 fs/namei.c:1851 walk_component fs/namei.c:2004 [inline] link_path_walk+0x72c/0xee0 fs/namei.c:2325 path_lookupat+0xa9/0x450 fs/namei.c:2478 filename_lookup+0x251/0x600 fs/namei.c:2508 vfs_statx+0x10c/0x480 fs/stat.c:229 vfs_fstatat fs/stat.c:267 [inline] __do_sys_newfstatat fs/stat.c:437 [inline] __se_sys_newfstatat fs/stat.c:431 [inline] __x64_sys_newfstatat+0x151/0x1e0 fs/stat.c:431 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fbbf73585f4 RSP: 002b:00007ffe4bd3ee58 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 00005605371f09a0 RCX: 00007fbbf73585f4 RDX: 00007ffe4bd3ee68 RSI: 00007ffe4bd3f2f8 RDI: 00000000ffffff9c RBP: 00007ffe4bd3eef8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe4bd3f2f8 R13: 00007ffe4bd3ee68 R14: 00005605371ce910 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10500 jiffies! g11693 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:25080 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5243 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6560 schedule+0xbf/0x180 kernel/sched/core.c:6636 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 46 Comm: kworker/u4:3 Not tainted 6.1.131-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:424 [inline] RIP: 0010:smp_call_function_many_cond+0x1fae/0x3460 kernel/smp.c:998 Code: 2f 44 89 ee 83 e6 01 31 ff e8 2e 4b 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 0a e8 b9 47 0b 00 e9 1b ff ff ff f3 90 <42> 0f b6 04 2b 84 c0 75 14 41 f7 07 01 00 00 00 0f 84 fe fe ff ff RSP: 0018:ffffc90000b775a0 EFLAGS: 00000293 RAX: ffffffff817f6229 RBX: 1ffff110171c8595 RCX: ffff88801eee1dc0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000b77980 R08: ffffffff817f61f2 R09: fffffbfff225724d R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000800000000 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8e42ca8 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f716a817238 CR3: 000000000d08e000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1166 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1334 [inline] text_poke_bp_batch+0x2bb/0x940 arch/x86/kernel/alternative.c:1534 text_poke_flush arch/x86/kernel/alternative.c:1725 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1732 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x12e/0x250 kernel/jump_label.c:207 static_key_enable+0x16/0x20 kernel/jump_label.c:220 toggle_allocation_gate+0xbf/0x480 mm/kfence/core.c:805 process_one_work+0x917/0x1260 kernel/workqueue.c:2292 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295