rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5821/1:b..l P7072/1:b..l rcu: (detected by 1, t=10502 jiffies, g=11081, q=332 ncpus=2) task:syz.0.203 state:R running task stack:25560 pid:7072 tgid:7065 ppid:5819 task_flags:0x40044c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6765 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6944 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] zap_pte_range mm/memory.c:1772 [inline] zap_pmd_range mm/memory.c:1834 [inline] zap_pud_range mm/memory.c:1863 [inline] zap_p4d_range mm/memory.c:1884 [inline] unmap_page_range+0xee3/0x4350 mm/memory.c:1905 unmap_single_vma+0x194/0x2b0 mm/memory.c:1951 unmap_vmas+0x22f/0x490 mm/memory.c:1995 exit_mmap+0x1c1/0xba0 mm/mmap.c:1284 __mmput+0x12a/0x410 kernel/fork.c:1356 mmput+0x62/0x70 kernel/fork.c:1378 exit_mm kernel/exit.c:570 [inline] do_exit+0x9ba/0x2d70 kernel/exit.c:925 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087 get_signal+0x24ed/0x26c0 kernel/signal.c:3036 arch_do_signal_or_restart+0x90/0x7e0 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:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbcd2d8d169 RSP: 002b:00007fbcd3c9e038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007fbcd2fa6080 RCX: 00007fbcd2d8d169 RDX: 0000000000010106 RSI: 00004000000000c0 RDI: 0000000000000004 RBP: 00007fbcd2e0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fbcd2fa6080 R15: 00007fff73bc9228 task:syz-executor state:R running task stack:22672 pid:5821 tgid:5821 ppid:5814 task_flags:0x400140 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6765 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7087 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:write_comp_data+0x0/0x90 kernel/kcov.c:240 Code: 48 8b 05 43 ef 49 7e 48 8b 80 20 16 00 00 c3 cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <49> 89 d2 49 89 f8 49 89 f1 65 48 8b 15 0f ef 49 7e 65 8b 05 10 ef RSP: 0018:ffffc9000301f8b0 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffffea0000cd1c40 RCX: ffffffff822896ea RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000000 R09: fffffbfff2dd8b98 R10: ffffffff96ec5cc7 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_read_lock include/linux/rcupdate.h:850 [inline] page_ext_get+0x4a/0x310 mm/page_ext.c:525 __page_table_check_zero+0xbf/0x360 mm/page_table_check.c:148 page_table_check_free include/linux/page_table_check.h:41 [inline] free_pages_prepare mm/page_alloc.c:1128 [inline] free_frozen_pages+0x6c2/0xfb0 mm/page_alloc.c:2660 vfree+0x174/0x950 mm/vmalloc.c:3383 __do_replace+0x7bf/0x9d0 net/ipv4/netfilter/ip_tables.c:1090 do_replace net/ipv4/netfilter/ip_tables.c:1141 [inline] do_ipt_set_ctl+0x956/0xbe0 net/ipv4/netfilter/ip_tables.c:1635 nf_setsockopt+0x8a/0xf0 net/netfilter/nf_sockopt.c:101 ip_setsockopt+0xcb/0xf0 net/ipv4/ip_sockglue.c:1424 tcp_setsockopt+0xa4/0x100 net/ipv4/tcp.c:4043 do_sock_setsockopt+0x222/0x480 net/socket.c:2303 __sys_setsockopt+0x1a0/0x230 net/socket.c:2328 __do_sys_setsockopt net/socket.c:2334 [inline] __se_sys_setsockopt net/socket.c:2331 [inline] __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2331 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f177258f05a RSP: 002b:00007ffeb574d9d8 EFLAGS: 00000206 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007ffeb574da60 RCX: 00007f177258f05a RDX: 0000000000000040 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000240 R09: 00007ffeb574de17 R10: 00007f177277b2e0 R11: 0000000000000206 R12: 00007f177277b280 R13: 00007ffeb574d9fc R14: 0000000000000000 R15: 00007f177277c000 rcu: rcu_preempt kthread timer wakeup didn't happen for 10557 jiffies! g11081 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=9659 rcu: rcu_preempt kthread starved for 10558 jiffies! g11081 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27552 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6857 schedule_timeout+0x124/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2024 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2226 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 1293 Comm: aoe_tx0 Not tainted 6.14.0-rc6-syzkaller-00145-g695caca9345a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:task_wait_context kernel/locking/lockdep.c:4788 [inline] RIP: 0010:check_wait_context kernel/locking/lockdep.c:4873 [inline] RIP: 0010:__lock_acquire+0x10b2/0x3c40 kernel/locking/lockdep.c:5178 Code: fc ff df 48 8b 7c 24 40 48 89 fe 83 e7 07 48 c1 ee 03 0f b6 34 16 48 89 fa 83 c2 03 40 38 f2 7c 09 40 84 f6 0f 85 af 2a 00 00 <45> 8b a5 d4 0a 00 00 45 85 e4 0f 85 48 02 00 00 41 be 05 00 00 00 RSP: 0018:ffffc90004887738 EFLAGS: 00000046 RAX: 0000000000000003 RBX: 0000000000000000 RCX: ffff888028792f30 RDX: 0000000000000007 RSI: 0000000000000000 RDI: 0000000000000004 RBP: dffffc0000000000 R08: 0000000000000002 R09: fffffbfff2dd8b99 R10: ffffffff96ec5ccf R11: 0000000000000002 R12: ffff888028792f29 R13: ffff888028792440 R14: 0000000000000000 R15: ffff888028792f80 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb4827785e8 CR3: 000000007e42a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:715 [inline] uart_write_room+0x126/0x940 drivers/tty/serial/serial_core.c:647 tty_write_room+0x63/0x90 drivers/tty/tty_ioctl.c:69 handle_tx+0x151/0x630 drivers/net/caif/caif_serial.c:226 __netdev_start_xmit include/linux/netdevice.h:5151 [inline] netdev_start_xmit include/linux/netdevice.h:5160 [inline] xmit_one net/core/dev.c:3800 [inline] dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3816 __dev_queue_xmit+0x7f0/0x43e0 net/core/dev.c:4652 dev_queue_xmit include/linux/netdevice.h:3313 [inline] tx+0xcc/0x190 drivers/block/aoe/aoenet.c:62 kthread+0x1e7/0x3c0 drivers/block/aoe/aoecmd.c:1237 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244