rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16348/1:b..l rcu: (detected by 1, t=10503 jiffies, g=86097, q=1580 ncpus=2) task:syz.7.1753 state:R running task stack:25656 pid:16348 tgid:16338 ppid:8165 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5282 [inline] __schedule+0x14ed/0x5040 kernel/sched/core.c:6894 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7221 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:unwind_next_frame+0x479/0x23d0 arch/x86/kernel/unwind_orc.c:520 Code: e9 5b 00 48 c7 c1 60 bf fa 8d 31 d2 84 c0 48 0f 45 d1 48 89 15 a8 b0 33 11 48 85 d2 0f 84 40 02 00 00 4c 8d 62 04 4c 8d 6a 05 <4c> 89 e0 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 6d 18 00 00 4c 89 e8 RSP: 0018:ffffc90004a370d8 EFLAGS: 00000286 RAX: 0000000000000000 RBX: ffffffff8fc3dbdc RCX: ffffffff8fc3dbe0 RDX: ffffffff9044e028 RSI: ffffffff9044e028 RDI: ffffffff8be08580 RBP: dffffc0000000000 R08: 0000000000000003 R09: ffffffff8e13efa0 R10: ffffc90004a371f8 R11: ffffffff81acb3b0 R12: ffffffff9044e02c R13: ffffffff9044e02d R14: ffffc90004a371a8 R15: ffffffff8fc3dbdc arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:165 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x23d/0x2a0 mm/page_alloc.c:1887 prep_new_page mm/page_alloc.c:1895 [inline] get_page_from_freelist+0x23a5/0x2440 mm/page_alloc.c:3955 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5264 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2505 shmem_alloc_folio mm/shmem.c:1902 [inline] shmem_alloc_and_add_folio+0x423/0xf40 mm/shmem.c:1944 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2539 shmem_get_folio mm/shmem.c:2645 [inline] shmem_write_begin+0x16c/0x330 mm/shmem.c:3298 generic_perform_write+0x2c5/0x900 mm/filemap.c:4314 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3473 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 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: 0033:0x7f02c658e1ff RSP: 002b:00007f02c7413df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000200000 RCX: 00007f02c658e1ff RDX: 0000000000200000 RSI: 00007f02bc200000 RDI: 0000000000000006 RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000001f71f R10: 0000000000003ffc R11: 0000000000000293 R12: 0000000000000006 R13: 00007f02c7413ef0 R14: 00007f02c7413eb0 R15: 00007f02bc200000 rcu: rcu_preempt kthread starved for 10548 jiffies! g86097 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:27904 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5282 [inline] __schedule+0x14ed/0x5040 kernel/sched/core.c:6894 __schedule_loop kernel/sched/core.c:6976 [inline] schedule+0x165/0x360 kernel/sched/core.c:6991 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x11b0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9b/0x2d0 kernel/rcu/tree.c:2297 kthread+0x389/0x480 kernel/kthread.c:467 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: 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+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc 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 43 5e 2b 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197e20 EFLAGS: 000002c2 RAX: 0000000001743143 RBX: ffffffff8197171e RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d99f7ca RDI: ffffffff8be085e0 RBP: ffffc90000197f10 R08: ffff8880b873375b R09: 1ffff110170e66eb R10: dffffc0000000000 R11: ffffed10170e66ec R12: ffffffff8fa24670 R13: 1ffff11003ad4b58 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125d0a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000040 CR3: 000000007b81e000 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+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