rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8918/1:b..l P8944/1:b..l P5835/1:b..l rcu: (detected by 0, t=10502 jiffies, g=30325, q=451 ncpus=2) task:syz-executor state:R running task stack:21720 pid:5835 tgid:5835 ppid:5814 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:-1 [inline] RIP: 0010:unwind_next_frame+0xe55/0x23d0 arch/x86/kernel/unwind_orc.c:600 Code: 85 eb 0b 00 00 48 8d 43 08 4c 39 f8 0f 97 c1 4c 39 e0 0f 96 c0 20 c8 3c 01 0f 85 d1 0b 00 00 48 89 df e8 ae 21 00 00 48 89 c3 <48> bd 00 00 00 00 00 fc ff df 48 8b 44 24 30 80 3c 28 00 4c 8b 7c RSP: 0018:ffffc9000401f818 EFLAGS: 00000202 RAX: ffffffff892e7964 RBX: ffffffff892e7964 RCX: 1ffff92000803f01 RDX: ffffffff9022ce92 RSI: 0000000000000002 RDI: ffffc9000401fcc8 RBP: 1ffff92000803f1e R08: 0000000000000001 R09: ffffffff8df41aa0 R10: dffffc0000000000 R11: ffffffff81acf3a0 R12: ffffc90004020000 R13: 1ffff92000803f1f R14: ffffc9000401f8e8 R15: ffffc90004018000 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 slab_free_hook mm/slub.c:2501 [inline] slab_free mm/slub.c:6670 [inline] kmem_cache_free+0x475/0x620 mm/slub.c:6781 sk_prot_free net/core/sock.c:2282 [inline] __sk_destruct+0x614/0x880 net/core/sock.c:2384 inet_release+0x144/0x190 net/ipv4/af_inet.c:437 __sock_release net/socket.c:662 [inline] sock_close+0xc3/0x240 net/socket.c:1455 __fput+0x44c/0xa70 fs/file_table.c:468 fput_close_sync+0x113/0x220 fs/file_table.c:573 __do_sys_close fs/open.c:1573 [inline] __se_sys_close fs/open.c:1558 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1558 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0a5898e3aa RSP: 002b:00007fffb6a5b7d0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f0a5898e3aa RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007fffb6a5b82c R08: 00007fffb6a5b11c R09: 0079746972756365 R10: 00007fffb6a5b180 R11: 0000000000000293 R12: 00000000000000aa R13: 00000000000927c0 R14: 000000000003f70f R15: 00007fffb6a5b880 task:dhcpcd-run-hook state:R running task stack:28088 pid:8944 tgid:8944 ppid:8943 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x2d8/0x3b0 kernel/locking/lockdep.c:5893 Code: 34 e2 10 00 00 00 00 eb b5 e8 94 6f bb 09 f7 c3 00 02 00 00 74 b9 65 48 8b 05 a4 ee e1 10 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 74 1f 72 ff cc 48 8d 3d 31 48 e7 RSP: 0000:ffffc90003387540 EFLAGS: 00000282 RAX: c567a77b448d4a00 RBX: 0000000000000202 RCX: 0000000000000046 RDX: 0000000000000001 RSI: ffffffff8d975e98 RDI: ffffffff8bc083e0 RBP: ffff88802471e6d8 R08: ffff88801c034cff R09: 1ffff1100380699f R10: dffffc0000000000 R11: ffffed10038069a0 R12: 0000000000000001 R13: 0000000000000001 R14: ffffffff8df41aa0 R15: ffff88802471db80 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] __page_table_check_zero+0x397/0x3e0 mm/page_table_check.c:145 page_table_check_alloc include/linux/page_table_check.h:35 [inline] post_alloc_hook+0x247/0x290 mm/page_alloc.c:1847 prep_new_page mm/page_alloc.c:1854 [inline] get_page_from_freelist+0x24e0/0x2580 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 folio_alloc_mpol_noprof mm/mempolicy.c:2505 [inline] vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2540 folio_prealloc+0x30/0x180 mm/memory.c:-1 wp_page_copy mm/memory.c:3719 [inline] do_wp_page+0x1231/0x5810 mm/memory.c:4180 handle_pte_fault mm/memory.c:6289 [inline] __handle_mm_fault mm/memory.c:6411 [inline] handle_mm_fault+0x14c5/0x32b0 mm/memory.c:6580 do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x71/0xd0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f6ce7b222cd RSP: 002b:00007ffe62af8960 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 00007f6ce7d2d000 RCX: 00007f6ce7a8bf07 RDX: 0000000000000000 RSI: 00007ffe62af8938 RDI: 0000000000000002 RBP: 0000563ff694ae60 R08: 00007f6ce7c1eb60 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000246 R12: 0000563ff694d060 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 task:syz.6.913 state:R running task stack:25752 pid:8918 tgid:8918 ppid:7657 task_flags:0x40004c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:422 [inline] RIP: 0010:unwind_next_frame+0xe64/0x23d0 arch/x86/kernel/unwind_orc.c:600 Code: 4c 39 e0 0f 96 c0 20 c8 3c 01 0f 85 d1 0b 00 00 48 89 df e8 ae 21 00 00 48 89 c3 48 bd 00 00 00 00 00 fc ff df 48 8b 44 24 30 <80> 3c 28 00 4c 8b 7c 24 10 74 08 4c 89 ff e8 a9 0b b3 00 49 89 1f RSP: 0018:ffffc900032f77b8 EFLAGS: 00000202 RAX: 1ffff9200065ef1a RBX: ffffffff8184abac RCX: 1ffff9200065ef01 RDX: ffffffff901680a4 RSI: 0000000000000002 RDI: ffffc900032f7e80 RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff8df41aa0 R10: dffffc0000000000 R11: ffffffff81acf3a0 R12: ffffc900032f8000 R13: 1ffff9200065ef13 R14: ffffc900032f7888 R15: ffffc900032f0000 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 slab_free_hook mm/slub.c:2501 [inline] slab_free mm/slub.c:6670 [inline] kmem_cache_free+0x475/0x620 mm/slub.c:6781 task_work_run+0x1d4/0x260 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x694/0x22f0 kernel/exit.c:971 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 __do_sys_exit_group kernel/exit.c:1123 [inline] __se_sys_exit_group kernel/exit.c:1121 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121 x64_sys_call+0x2210/0x2210 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2e9d98f749 RSP: 002b:00007ffd39d8d368 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2e9d98f749 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffd39d8d3cc R08: 0000000739d8d45f R09: 00000000000927c0 R10: 0000000000001834 R11: 0000000000000246 R12: 0000000000000022 R13: 00000000000927c0 R14: 000000000003f36c R15: 00007ffd39d8d420 rcu: rcu_preempt kthread starved for 10617 jiffies! g30325 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:27480 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 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 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 3e b4 b6 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 73 c1 0e 00 f3 0f 1e fa fb f4 13 b4 b6 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197e20 EFLAGS: 000002c2 RAX: 00000000004b2101 RBX: ffffffff819713be RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d792008 RDI: ffffffff8bc083e0 RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8f822170 R13: 1ffff1100385fb70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007febef372100 CR3: 0000000075d4b000 CR4: 0000000000350ef0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1be/0x4d0 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147