rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5187/1:b..l P12636/1:b..l rcu: (detected by 0, t=10502 jiffies, g=89449, q=336 ncpus=2) task:syz-executor state:R running task stack:23704 pid:12636 tgid:12636 ppid:12616 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:217 [inline] RIP: 0010:unwind_next_frame+0x19b/0x20b0 arch/x86/kernel/unwind_orc.c:510 Code: ba 00 00 00 00 00 fc ff df 48 c1 e9 03 80 3c 11 00 0f 85 5f 17 00 00 4d 8b 7d 48 3c 01 49 83 df 00 4d 85 ff 0f 84 31 09 00 00 <49> 81 ff 00 00 00 81 0f 82 5b 02 00 00 49 81 ff f0 23 7c 8b 0f 83 RSP: 0018:ffffc90003126e30 EFLAGS: 00000286 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 1ffff92000624ddd RDX: dffffc0000000000 RSI: ffffffff8bf2b300 RDI: ffffffff8dd7bf20 RBP: ffffc90003126ee8 R08: 000000009ecfde30 R09: 0000000009ecfde3 R10: 0000000000000002 R11: ffff888022b954b0 R12: ffffc90003126ef0 R13: ffffc90003126ea0 R14: ffffc90003126ed5 R15: ffffffff817b7dde arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:165 __set_page_owner+0x91/0x560 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1857 prep_new_page mm/page_alloc.c:1865 [inline] get_page_from_freelist+0xd0b/0x31a0 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x25f/0x2430 mm/page_alloc.c:5210 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486 alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline] alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2577 pagetable_alloc_noprof include/linux/mm.h:3190 [inline] pmd_alloc_one_noprof include/asm-generic/pgalloc.h:143 [inline] __pmd_alloc+0x3b/0x9c0 mm/memory.c:6666 pmd_alloc include/linux/mm.h:3106 [inline] copy_pmd_range mm/memory.c:1372 [inline] copy_pud_range mm/memory.c:1429 [inline] copy_p4d_range mm/memory.c:1453 [inline] copy_page_range+0x4620/0x6780 mm/memory.c:1535 dup_mmap+0xbea/0x20e0 mm/mmap.c:1827 dup_mm kernel/fork.c:1529 [inline] copy_mm kernel/fork.c:1581 [inline] copy_process+0x3b9f/0x7430 kernel/fork.c:2221 kernel_clone+0xfc/0x910 kernel/fork.c:2651 __do_sys_clone+0xce/0x120 kernel/fork.c:2792 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc379d85e93 RSP: 002b:00007ffd6acc1468 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc379d85e93 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 00005555833937d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 00000000000e257f R15: 00007ffd6acc1600 task:udevd state:R running task stack:24728 pid:5187 tgid:5187 ppid:1 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x183/0x2d0 kernel/locking/lockdep.c:5893 Code: 0f c1 05 f8 00 19 12 83 f8 01 0f 85 03 01 00 00 9c 58 f6 c4 02 0f 85 ee 00 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 8d b9 18 12 0f 85 32 01 00 00 48 83 c4 18 5b 41 5c 41 RSP: 0018:ffffc9000472f590 EFLAGS: 00000206 RAX: ee650b20a5666e00 RBX: ffffffff8e3c96a0 RCX: ffffc9000472f59c RDX: 0000000000000000 RSI: ffffffff8daa7f9d RDI: ffffffff8bf2b380 RBP: 0000000000000001 R08: 0000000000000001 R09: 00000000ffffffff R10: 0000000000000002 R11: 0000000000035d4e R12: ffffffff816cb9a4 R13: 0000000000000206 R14: ffff88807bec4980 R15: 0000000000000001 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x3f9/0x20b0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5263 [inline] kmem_cache_alloc_noprof+0x25e/0x770 mm/slub.c:5270 lsm_file_alloc security/security.c:169 [inline] security_file_alloc+0x34/0x2b0 security/security.c:2380 init_file+0x93/0x4c0 fs/file_table.c:159 alloc_empty_file+0x73/0x1e0 fs/file_table.c:241 path_openat+0xde/0x3140 fs/namei.c:4773 do_filp_open+0x20b/0x470 fs/namei.c:4814 do_sys_openat2+0x121/0x290 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1447 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f255dea7407 RSP: 002b:00007ffe7b894ce0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f255e699880 RCX: 00007f255dea7407 RDX: 0000000000080141 RSI: 000055913c74202e RDI: ffffffffffffff9c RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000001a4 R11: 0000000000000202 R12: 00000000ffffffff R13: 00000000ffffffff R14: ffffffffffffffff R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10587 jiffies! g89449 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:28432 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 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 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: b6 5f 02 c3 cc cc cc cc 0f 1f 00 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 13 39 12 00 fb f4 cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6 RAX: 000000000241fb31 RBX: 0000000000000001 RCX: ffffffff8b7826d9 RDX: 0000000000000000 RSI: ffffffff8dace031 RDI: ffffffff8bf2b380 RBP: ffffed1003b56498 R08: 0000000000000001 R09: ffffed10170a673d R10: ffff8880b85339eb R11: ffff88801dab2ff0 R12: 0000000000000001 R13: ffff88801dab24c0 R14: ffffffff9088b8d0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881249f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffffffffffe70 CR3: 00000000687e3000 CR4: 00000000003526f0 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+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x38d/0x510 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x148