rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P23244/1:b..l P23236/1:b..l rcu: (detected by 0, t=10506 jiffies, g=134193, q=583 ncpus=2) task:syz.2.4322 state:R running task stack:26584 pid:23236 tgid:23235 ppid:16586 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7228 preempt_schedule_notrace+0x5f/0xd0 kernel/sched/core.c:7502 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:753 rcu_read_lock_held_common kernel/rcu/update.c:109 [inline] rcu_read_lock_held+0x1e/0x50 kernel/rcu/update.c:349 lookup_page_ext+0x6e/0x100 mm/page_ext.c:258 page_ext_get+0x58/0x1a0 mm/page_ext.c:532 __folio_copy_owner+0x4d/0x660 mm/page_owner.c:390 folio_copy_owner include/linux/page_owner.h:44 [inline] folio_migrate_flags+0xedd/0x13f0 mm/migrate.c:846 __migrate_folio.isra.0+0x38d/0x4c0 mm/migrate.c:878 move_to_new_folio+0x29b/0x4e0 mm/migrate.c:1102 migrate_folio_move mm/migrate.c:1382 [inline] migrate_folios_move mm/migrate.c:1738 [inline] migrate_pages_batch+0x28e8/0x45c0 mm/migrate.c:1994 migrate_pages_sync+0x12c/0x880 mm/migrate.c:2024 migrate_pages+0x1a83/0x2850 mm/migrate.c:2133 migrate_to_node mm/mempolicy.c:1319 [inline] do_migrate_pages+0x488/0x740 mm/mempolicy.c:1418 kernel_migrate_pages+0x560/0x700 mm/mempolicy.c:1932 __do_sys_migrate_pages mm/mempolicy.c:1950 [inline] __se_sys_migrate_pages mm/mempolicy.c:1946 [inline] __x64_sys_migrate_pages+0x96/0x100 mm/mempolicy.c:1946 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f67ceb9ce59 RSP: 002b:00007f67cfad9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000100 RAX: ffffffffffffffda RBX: 00007f67cee15fa0 RCX: 00007f67ceb9ce59 RDX: 0000200000000000 RSI: 0000000000000005 RDI: 0000000000000000 RBP: 00007f67cec32e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000200000000040 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f67cee16038 R14: 00007f67cee15fa0 R15: 00007fff661f8148 task:syz.9.4324 state:R running task stack:27912 pid:23244 tgid:23244 ppid:14406 task_flags:0x40004c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7228 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7552 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa00 kernel/entry/common.c:167 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:679 RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 7b 80 2e 12 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 c6 74 f6 0e 0f 82 ac 02 00 00 8b 35 8e a8 f6 0e 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 1d 80 2e 12 0f 85 ec 02 00 00 48 83 c4 RSP: 0018:ffffc9000657f500 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8df33a44 RDI: ffffffff8c1e7180 RBP: ffffffff8e7e60c0 R08: 000000002cf0a6e3 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:840 [inline] class_rcu_constructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2705 [inline] slab_free mm/slub.c:6405 [inline] kmem_cache_free+0x127/0x6b0 mm/slub.c:6532 anon_vma_chain_free mm/rmap.c:147 [inline] unlink_anon_vmas+0x228/0x8e0 mm/rmap.c:514 free_pgtables+0x299/0xd80 mm/memory.c:401 exit_mmap+0x44c/0xa00 mm/mmap.c:1312 __mmput+0x12a/0x410 kernel/fork.c:1182 mmput+0x67/0x80 kernel/fork.c:1205 exit_mm kernel/exit.c:610 [inline] do_exit+0x8b1/0x2ae0 kernel/exit.c:992 __do_sys_exit kernel/exit.c:1114 [inline] __se_sys_exit kernel/exit.c:1112 [inline] __x64_sys_exit+0x42/0x50 kernel/exit.c:1112 x64_sys_call+0x152e/0x1530 arch/x86/include/generated/asm/syscalls_64.h:61 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f38c059ce59 RSP: 002b:00007f38c14c0ef8 EFLAGS: 00000246 ORIG_RAX: 000000000000003c RAX: ffffffffffffffda RBX: 0000000000000058 RCX: 00007f38c059ce59 RDX: 00007f38c14c19c8 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f38c0632e6f R08: 0000000000000000 R09: 0000000000000058 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f38c0816038 R14: 00007f38c0815fa0 R15: 00007ffe38d0e698 rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g134193 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=93211 rcu: rcu_preempt kthread starved for 10506 jiffies! g134193 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28840 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7322 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 23250 Comm: syz.3.4325 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:mark_usage kernel/locking/lockdep.c:4674 [inline] RIP: 0010:__lock_acquire+0x48f/0x1a40 kernel/locking/lockdep.c:5191 Code: 03 00 00 00 48 89 de 48 89 ef e8 1c ef ff ff 85 c0 0f 84 14 ff ff ff 8b 85 80 0b 00 00 ba 07 00 00 00 85 c0 0f 85 72 03 00 00 08 00 00 00 48 89 de 48 89 ef e8 f1 ee ff ff 85 c0 0f 84 e9 fe RSP: 0018:ffffc90000a08ca8 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff88805323b0e0 RCX: 0000000000000000 RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000040 RBP: ffff88805323a540 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000007 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001 FS: 00007f91ce1b16c0(0000) GS:ffff8881243e7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000131000 CR3: 00000000566bd000 CR4: 00000000003526f0 Call Trace: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:840 [inline] advance_sched+0x718/0xd20 net/sched/sch_taprio.c:992 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 96 bd 46 f6 48 89 df e8 1e 0d 47 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 a5 1e 36 f6 65 8b 05 ae 38 75 08 85 c0 74 16 5b RSP: 0018:ffffc9000d3bfb28 EFLAGS: 00000246 RAX: 0000000000000006 RBX: ffffffff9b2333d8 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8df596ca RDI: ffffffff8c1e7180 RBP: 0000000000000286 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: ffffffffffffffff R12: ffffffff9b233140 R13: 0000000000000001 R14: ffffc9000d3bfc80 R15: ffffffff9b23331c class_raw_spinlock_irqsave_destructor include/linux/spinlock.h:571 [inline] __do_adjtimex+0x892/0xe70 kernel/time/timekeeping.c:2953 do_adjtimex+0xa0/0x370 kernel/time/timekeeping.c:2996 do_clock_adjtime kernel/time/posix-timers.c:1169 [inline] __do_sys_clock_adjtime+0x177/0x290 kernel/time/posix-timers.c:1181 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f91cd39ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f91ce1b1028 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00007f91cd616090 RCX: 00007f91cd39ce59 RDX: 0000000000000000 RSI: 0000200000000340 RDI: 0000000000000000 RBP: 00007f91cd432e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f91cd616128 R14: 00007f91cd616090 R15: 00007ffdc23a2508