rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5826/1:b..l P5825/1:b..l P6010/1:b..l rcu: (detected by 0, t=10503 jiffies, g=7549, q=2737788 ncpus=2) task:syz.3.42 state:R running task stack:23680 pid:6010 tgid:6009 ppid:5828 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x1850/0x4c30 kernel/sched/core.c:6756 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6935 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6959 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0x179/0x200 kernel/softirq.c:389 tun_rx_batched+0x732/0x8f0 tun_get_user+0x30d6/0x4890 drivers/net/tun.c:2007 tun_chr_write_iter+0x10d/0x1f0 drivers/net/tun.c:2053 new_sync_write fs/read_write.c:586 [inline] vfs_write+0xaeb/0xd30 fs/read_write.c:679 ksys_write+0x18f/0x2b0 fs/read_write.c:731 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2a2437d2ff RSP: 002b:00007f2a251c6000 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f2a24535fa0 RCX: 00007f2a2437d2ff RDX: 0000000000000036 RSI: 0000000020000000 RDI: 00000000000000c8 RBP: 00007f2a243f175e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000036 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f2a24535fa0 R15: 00007ffe5a705b48 task:syz-executor state:R running task stack:19936 pid:5825 tgid:5825 ppid:5822 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x1850/0x4c30 kernel/sched/core.c:6756 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6935 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6959 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1200 [inline] copy_pmd_range+0x74aa/0x7eb0 mm/memory.c:1261 copy_pud_range mm/memory.c:1298 [inline] copy_p4d_range mm/memory.c:1322 [inline] copy_page_range+0x99f/0xe90 mm/memory.c:1420 dup_mmap kernel/fork.c:745 [inline] dup_mm kernel/fork.c:1672 [inline] copy_mm+0x122b/0x1f60 kernel/fork.c:1721 copy_process+0x1845/0x3d50 kernel/fork.c:2372 kernel_clone+0x226/0x8f0 kernel/fork.c:2784 __do_sys_clone kernel/fork.c:2927 [inline] __se_sys_clone kernel/fork.c:2911 [inline] __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2911 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3c0db75093 RSP: 002b:00007fff7eb13788 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f3c0db75093 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 000055555f3a97d0 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000011b4f R14: 0000000000011adf R15: 00007fff7eb13910 task:syz-executor state:R running task stack:20544 pid:5826 tgid:5826 ppid:5824 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x1850/0x4c30 kernel/sched/core.c:6756 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6935 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6959 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1200 [inline] copy_pmd_range+0x74aa/0x7eb0 mm/memory.c:1261 copy_pud_range mm/memory.c:1298 [inline] copy_p4d_range mm/memory.c:1322 [inline] copy_page_range+0x99f/0xe90 mm/memory.c:1420 dup_mmap kernel/fork.c:745 [inline] dup_mm kernel/fork.c:1672 [inline] copy_mm+0x122b/0x1f60 kernel/fork.c:1721 copy_process+0x1845/0x3d50 kernel/fork.c:2372 kernel_clone+0x226/0x8f0 kernel/fork.c:2784 __do_sys_clone kernel/fork.c:2927 [inline] __se_sys_clone kernel/fork.c:2911 [inline] __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2911 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdfdad75093 RSP: 002b:00007ffd128a7d88 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdfdad75093 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 00005555649fd7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000011b70 R14: 0000000000011a6c R15: 00007ffd128a7f10 rcu: rcu_preempt kthread starved for 2625 jiffies! g7549 f0x2 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:25848 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x1850/0x4c30 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 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: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.12.0-next-20241122-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: 89 fb e8 23 00 00 00 48 8b 3d 94 28 8d 0c 48 89 de 5b e9 03 d4 5e 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 00 d6 03 00 65 8b 15 e0 5b RSP: 0018:ffffc90000157550 EFLAGS: 00000246 RAX: 0000000000000100 RBX: 0000000000000000 RCX: ffff88801cebda00 RDX: ffff88801cebda00 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 1ffff11035962f23 R08: ffffffff8a234625 R09: 1ffffffff2030be6 R10: dffffc0000000000 R11: ffffffff8a232920 R12: dffffc0000000000 R13: ffff8881af1cc140 R14: ffff8881acb17918 R15: ffff8881acb178c0 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b3001fffc CR3: 0000000060952000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ip_rcv_finish_core+0x692/0x1b50 net/ipv4/ip_input.c:377 ip_rcv_finish+0x14a/0x560 net/ipv4/ip_input.c:445 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5672 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5785 process_backlog+0x662/0x15b0 net/core/dev.c:6117 __napi_poll+0xcb/0x490 net/core/dev.c:6877 napi_poll net/core/dev.c:6946 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:7068 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 run_ksoftirqd+0xca/0x130 kernel/softirq.c:943 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