rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P15118/1:b..l (detected by 0, t=10503 jiffies, g=97869, q=55 ncpus=2) task:syz-executor state:R running task stack:21072 pid:15118 ppid:15110 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:__nr_to_section include/linux/mmzone.h:1695 [inline] RIP: 0010:__pfn_to_section include/linux/mmzone.h:1803 [inline] RIP: 0010:lookup_page_ext mm/page_ext.c:274 [inline] RIP: 0010:page_ext_get+0x12a/0x2a0 mm/page_ext.c:158 Code: 20 00 74 0c 48 c7 c7 e0 2f c4 96 e8 c0 e1 f5 ff 48 8b 05 39 0c e9 14 48 85 c0 74 42 4c 89 f1 48 c1 e9 16 4c 8d 3c c8 4c 89 f8 <48> c1 e8 03 42 80 3c 20 00 74 08 4c 89 ff e8 93 e1 f5 ff 4d 8b 3f RSP: 0018:ffffc90006c07528 EFLAGS: 00000246 RAX: ffff88823ffef000 RBX: ffffffff81db22ae RCX: 0000000000000000 RDX: 0000000000000000 RSI: 000000000007202f RDI: 00000003ffffffff RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff215c449 R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: dffffc0000000000 R13: 0000000000000000 R14: 000000000007202f R15: ffff88823ffef000 __page_table_check_zero+0x134/0x4b0 mm/page_table_check.c:146 page_table_check_free include/linux/page_table_check.h:46 [inline] free_pages_prepare mm/page_alloc.c:1460 [inline] free_pcp_prepare mm/page_alloc.c:1509 [inline] free_unref_page_prepare+0x8c4/0x9a0 mm/page_alloc.c:3384 free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3525 release_pages+0x1f92/0x2200 mm/swap.c:1035 __pagevec_release+0x6d/0xe0 mm/swap.c:1055 pagevec_release include/linux/pagevec.h:71 [inline] folio_batch_release include/linux/pagevec.h:135 [inline] shmem_undo_range+0x75b/0x2050 mm/shmem.c:946 shmem_truncate_range mm/shmem.c:1062 [inline] shmem_evict_inode+0x248/0xa40 mm/shmem.c:1171 evict+0x485/0x870 fs/inode.c:705 __dentry_kill+0x431/0x650 fs/dcache.c:611 dentry_kill+0xb8/0x290 fs/dcache.c:-1 dput+0xfa/0x1d0 fs/dcache.c:918 __fput+0x5e0/0x920 fs/file_table.c:328 task_work_run+0x1ca/0x250 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f6a777909f7 RSP: 002b:00007ffc17261828 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f6a77811d7d RCX: 00007f6a777909f7 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc172618e0 RBP: 00007ffc172618e0 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc17262970 R13: 00007f6a77811d7d R14: 000000000012b542 R15: 00007ffc172629b0 rcu: rcu_preempt kthread starved for 10543 jiffies! g97869 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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:26880 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:742 Code: 48 89 df e8 b7 3b af f7 e9 4c ff ff ff e8 dd 07 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d 97 d4 64 00 fb f4 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48 RSP: 0000:ffffffff8c807d88 EFLAGS: 000002c6 RAX: da1795ee7f2c0000 RBX: ffffffff8a21ce97 RCX: da1795ee7f2c0000 RDX: 0000000000000001 RSI: ffffffff8a8c0580 RDI: ffffffff8adef760 RBP: ffffffff8c807ec0 R08: dffffc0000000000 R09: ffffed10171c6afa R10: ffffed10171c6afa R11: 1ffff110171c6af9 R12: 0000000000000000 R13: dffffc0000000000 R14: ffffffff8c8bc740 R15: 1ffffffff1c3ed96 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c4326ec CR3: 0000000033e13000 CR4: 00000000003506f0 Call Trace: default_idle_call+0x84/0xc0 kernel/sched/idle.c:109 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1fc/0x570 kernel/sched/idle.c:303 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:401 rest_init+0x2dc/0x300 init/main.c:745 arch_call_rest_init+0xa/0xa init/main.c:905 start_kernel+0x490/0x539 init/main.c:1152 secondary_startup_64_no_verify+0xcf/0xdb