rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5375/1:b..l rcu: (detected by 1, t=10503 jiffies, g=8341, q=1562098 ncpus=2) task:syz.3.18 state:R running task stack:25104 pid:5375 tgid:5365 ppid:5225 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0x185a/0x4b70 kernel/sched/core.c:6690 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7012 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:unwind_next_frame+0x0/0x22d0 arch/x86/kernel/unwind_orc.c:469 Code: cc cc 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 91 4c 89 f7 e8 83 22 ba 00 eb 87 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 55 41 57 41 56 41 55 41 54 53 48 81 ec 98 00 00 00 49 RSP: 0018:ffffc900045fed78 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffc900045fed80 RCX: ffffffff9179d000 RDX: dffffc0000000000 RSI: ffffffff81809fa8 RDI: ffffc900045fed80 RBP: ffffc900045fee10 R08: 0000000000000000 R09: ffffc900045fee70 R10: ffffc900045fedd0 R11: ffffffff8180a070 R12: ffff888025501e00 R13: ffffffff8180a070 R14: ffffc900045fee60 R15: 0000000000000000 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122 save_stack+0xfb/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x76/0x430 mm/page_owner.c:297 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1108 [inline] free_unref_folios+0xee2/0x18a0 mm/page_alloc.c:2686 folios_put_refs+0x76c/0x860 mm/swap.c:1007 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x64c/0x1cf0 mm/shmem.c:1032 shmem_truncate_range mm/shmem.c:1144 [inline] shmem_evict_inode+0x29b/0xa80 mm/shmem.c:1272 evict+0x4e8/0x9b0 fs/inode.c:725 __dentry_kill+0x20d/0x630 fs/dcache.c:615 dput+0x19f/0x2b0 fs/dcache.c:857 __fput+0x5d2/0x880 fs/file_table.c:439 task_work_run+0x24f/0x310 kernel/task_work.c:239 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0xa2f/0x28e0 kernel/exit.c:939 do_group_exit+0x207/0x2c0 kernel/exit.c:1088 get_signal+0x16a3/0x1740 kernel/signal.c:2917 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0xc9/0x370 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe87ff7dff9 RSP: 002b:00007fe880d91038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007fe880136058 RCX: 00007fe87ff7dff9 RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000005 RBP: 00007fe87fff0296 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fe880136058 R15: 00007ffcb1bc0aa8 rcu: rcu_preempt kthread starved for 10478 jiffies! g8341 f0x2 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:25328 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0x185a/0x4b70 kernel/sched/core.c:6690 __schedule_loop kernel/sched/core.c:6767 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6782 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 24 Comm: ksoftirqd/1 Not tainted 6.12.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__sanitizer_cov_trace_switch+0x6f/0x120 Code: 48 83 f8 07 0f 85 ba 00 00 00 41 b8 07 00 00 00 4d 85 d2 75 24 e9 aa 00 00 00 41 b8 01 00 00 00 4d 85 d2 75 14 e9 9a 00 00 00 <41> b8 05 00 00 00 4d 85 d2 0f 84 8b 00 00 00 4c 8b 4c 24 20 65 4c RSP: 0018:ffffc900001e73f8 EFLAGS: 00000246 RAX: 0000000000000003 RBX: ffff8881f3f82ce8 RCX: ffff88801da88000 RDX: 0000000000000100 RSI: ffffffff8fd475f0 RDI: 0000000000000003 RBP: ffff8881f3f82c98 R08: ffffffff89df0da7 R09: ffffffff89d27367 R10: 0000000000000002 R11: ffffffff89df0ca0 R12: 0000000000000003 R13: ffff88801b75ef00 R14: ffff8881f562f000 R15: 0000000000000140 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffcff8fb75c CR3: 00000000770c6000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: nf_nat_ipv4_fn net/netfilter/nf_nat_proto.c:635 [inline] nf_nat_ipv4_local_in+0x123/0x770 net/netfilter/nf_nat_proto.c:733 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5666 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5779 process_backlog+0x662/0x15b0 net/core/dev.c:6111 __napi_poll+0xcb/0x490 net/core/dev.c:6775 napi_poll net/core/dev.c:6844 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:6966 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 run_ksoftirqd+0xca/0x130 kernel/softirq.c:927 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244