rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7869/1:b..l P7837/1:b..l rcu: (detected by 0, t=10502 jiffies, g=31177, q=854 ncpus=2) task:syz.3.502 state:R running task stack:25592 pid:7837 tgid:7837 ppid:5819 task_flags:0x40004c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7188 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7512 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x14f/0x730 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 a1 67 14 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 8b f2 9d 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 5b 83 6e ff cc 48 8d 3d 58 d2 94 RSP: 0018:ffffc90004e66f78 EFLAGS: 00000286 RAX: c0abfbe20923b100 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 000000005a44979c RSI: ffffffff8e247e65 RDI: ffffffff8c2892e0 RBP: ffffffff81770256 R08: ffffffff81770256 R09: ffffffff8e95cce0 R10: dffffc0000000000 R11: ffffffff81b0f560 R12: 0000000000000002 R13: ffffffff8e95cce0 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] class_rcu_constructor include/linux/rcupdate.h:1181 [inline] unwind_next_frame+0xc3/0x2550 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1394 [inline] free_unref_folios+0xcec/0x1480 mm/page_alloc.c:2996 folios_put_refs+0x789/0x8d0 mm/swap.c:1002 folio_batch_release include/linux/folio_batch.h:101 [inline] shmem_undo_range+0x52c/0x1660 mm/shmem.c:1149 shmem_truncate_range mm/shmem.c:1277 [inline] shmem_evict_inode+0x289/0xae0 mm/shmem.c:1407 evict+0x61e/0xb10 fs/inode.c:841 __dentry_kill+0x1a2/0x5e0 fs/dcache.c:670 finish_dput+0xc9/0x480 fs/dcache.c:879 __fput+0x691/0xa60 fs/file_table.c:518 task_work_run+0x1d9/0x270 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x70f/0x22c0 kernel/exit.c:975 do_group_exit+0x21b/0x2d0 kernel/exit.c:1117 __do_sys_exit_group kernel/exit.c:1128 [inline] __se_sys_exit_group kernel/exit.c:1126 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1126 x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe04819c819 RSP: 002b:00007fff798d5398 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe04819c819 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fff798d53fc R08: 0000000000000000 R09: 000000000000001f R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000054 R13: 000000000000001f R14: 00000000000469b6 R15: 00007fff798d5450 task:syz.4.511 state:R running task stack:26008 pid:7869 tgid:7864 ppid:5833 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7188 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7512 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x14f/0x730 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x2d7/0x3c0 kernel/locking/lockdep.c:5893 Code: 06 9e 11 00 00 00 00 eb b5 e8 05 36 14 0a f7 c3 00 02 00 00 74 b9 65 48 8b 05 f5 c0 9d 11 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 c5 51 6e ff cc 48 8d 3d 32 a4 94 RSP: 0018:ffffc90003407438 EFLAGS: 00000282 RAX: f2224dc7656e3e00 RBX: 0000000000000202 RCX: 0000000000000046 RDX: 0000000000000001 RSI: ffffffff8e247e65 RDI: ffffffff8c2892e0 RBP: ffff88803178aa78 R08: ffffffff82396a49 R09: ffffffff8e95cce0 R10: dffffc0000000000 R11: fffffbfff206671f R12: 0000000000000001 R13: 0000000000000001 R14: ffffffff8e95cce0 R15: ffff888031789ec0 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:869 [inline] percpu_ref_put_many include/linux/percpu-refcount.h:337 [inline] percpu_ref_put+0xf9/0x180 include/linux/percpu-refcount.h:351 css_put include/linux/cgroup_refcnt.h:79 [inline] __mem_cgroup_charge+0x149/0x1e0 mm/memcontrol.c:4822 mem_cgroup_charge include/linux/memcontrol.h:664 [inline] shmem_alloc_and_add_folio+0x7cd/0xf80 mm/shmem.c:1985 shmem_get_folio_gfp+0x5a9/0x1670 mm/shmem.c:2564 shmem_fault+0x179/0x390 mm/shmem.c:2765 __do_fault+0x138/0x2a0 mm/memory.c:5458 do_read_fault mm/memory.c:5893 [inline] do_fault mm/memory.c:6027 [inline] do_pte_missing+0x2093/0x33f0 mm/memory.c:4550 handle_pte_fault mm/memory.c:6411 [inline] __handle_mm_fault mm/memory.c:6549 [inline] handle_mm_fault+0x1bd7/0x3170 mm/memory.c:6718 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x1683/0x2720 mm/gup.c:1428 populate_vma_page_range+0x2be/0x3c0 mm/gup.c:1860 __mm_populate+0x25f/0x390 mm/gup.c:1963 mm_populate include/linux/mm.h:4132 [inline] vm_mmap_pgoff+0x3aa/0x4f0 mm/util.c:586 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa91d99c819 RSP: 002b:00007fa91e7fd028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fa91dc16180 RCX: 00007fa91d99c819 RDX: 000000000000000f RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007fa91da32c91 R08: ffffffffffffffff R09: 0000000000001000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa91dc16218 R14: 00007fa91dc16180 R15: 00007ffc93905118 rcu: rcu_preempt kthread starved for 825 jiffies! g31177 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:27736 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5387 [inline] __schedule+0x17b4/0x5680 kernel/sched/core.c:7188 __schedule_loop kernel/sched/core.c:7267 [inline] schedule+0x164/0x360 kernel/sched/core.c:7282 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 2b 73 02 e9 fe 1f 5a f5 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 93 40 13 00 fb f4 d7 1f 5a f5 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffc90000197e20 EFLAGS: 00000246 RAX: 0000000000b73d3f RBX: ffffffff819a9e9a RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8dfd1e21 RDI: ffffffff8c2892e0 RBP: ffffc90000197f10 R08: ffff8880b87339db R09: 1ffff110170e673b R10: dffffc0000000000 R11: ffffed10170e673c R12: 0000000000000001 R13: 1ffff11003b5f000 R14: 0000000000000001 R15: 1ffff11003b5f000 FS: 0000000000000000(0000) GS:ffff888125325000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000140 CR3: 000000005c6e2000 CR4: 0000000000350ef0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x36a/0x5f0 kernel/sched/idle.c:352 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147