rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13526/3:b..l rcu: (detected by 1, t=10502 jiffies, g=85517, q=167 ncpus=2) task:syz.1.2190 state:R running task stack:25544 pid:13526 tgid:13518 ppid:5847 task_flags:0x400040 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_is_held_type+0x137/0x190 kernel/locking/lockdep.c:5945 Code: 01 75 44 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 4c 41 f7 c4 00 02 00 00 74 01 fb 65 48 8b 05 09 2a 45 07 <48> 3b 44 24 08 75 43 89 d8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc9000451eb38 EFLAGS: 00000206 RAX: 85de207f971b1300 RBX: 0000000000000001 RCX: 85de207f971b1300 RDX: ffff888027cb3c80 RSI: ffffffff8d9d1546 RDI: ffffffff8bc076e0 RBP: 00000000ffffffff R08: ffffc9000451ee80 R09: ffffc9000451ee90 R10: ffffc9000451ece0 R11: fffff520008a3d9e R12: 0000000000000246 R13: ffff888027cb3c80 R14: ffffffff8e13d2e0 R15: 0000000000000001 __in6_dev_get include/net/addrconf.h:347 [inline] ip6_ignore_linkdown include/net/addrconf.h:443 [inline] find_match+0xf1/0xc90 net/ipv6/route.c:780 __find_rr_leaf+0x23a/0x6d0 net/ipv6/route.c:868 find_rr_leaf net/ipv6/route.c:889 [inline] rt6_select net/ipv6/route.c:933 [inline] fib6_table_lookup+0x39f/0xa80 net/ipv6/route.c:2233 ip6_pol_route+0x222/0x1180 net/ipv6/route.c:2269 pol_lookup_func include/net/ip6_fib.h:617 [inline] fib6_rule_lookup+0x348/0x6f0 net/ipv6/fib6_rules.c:125 ip6_route_output_flags_noref net/ipv6/route.c:2684 [inline] ip6_route_output_flags+0x364/0x5d0 net/ipv6/route.c:2696 ip6_dst_lookup_tail+0x299/0x1510 net/ipv6/ip6_output.c:1169 ip6_dst_lookup_flow+0x47/0xe0 net/ipv6/ip6_output.c:1272 sctp_v6_get_dst+0xffa/0x1bc0 net/sctp/ipv6.c:385 sctp_transport_route+0x118/0x2f0 net/sctp/transport.c:457 sctp_packet_config+0x478/0xd90 net/sctp/output.c:103 sctp_packet_singleton+0x158/0x330 net/sctp/outqueue.c:777 sctp_outq_flush_ctrl net/sctp/outqueue.c:914 [inline] sctp_outq_flush+0x4f0/0x3140 net/sctp/outqueue.c:1212 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:-1 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1204 [inline] sctp_do_sm+0x5332/0x5a20 net/sctp/sm_sideeffect.c:1175 sctp_primitive_ASSOCIATE+0x95/0xc0 net/sctp/primitive.c:73 __sctp_connect+0x947/0xd50 net/sctp/socket.c:1234 sctp_connect net/sctp/socket.c:4819 [inline] sctp_inet_connect+0x12e/0x1e0 net/sctp/socket.c:4834 __sys_connect_file net/socket.c:2102 [inline] __sys_connect+0x316/0x440 net/socket.c:2121 __do_sys_connect net/socket.c:2127 [inline] __se_sys_connect net/socket.c:2124 [inline] __x64_sys_connect+0x7a/0x90 net/socket.c:2124 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb1be78eec9 RSP: 002b:00007fb1bf685038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 00007fb1be9e6180 RCX: 00007fb1be78eec9 RDX: 000000000000001c RSI: 0000200000000240 RDI: 0000000000000005 RBP: 00007fb1be811f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb1be9e6218 R14: 00007fb1be9e6180 R15: 00007fb1beb0fa28 rcu: rcu_preempt kthread starved for 10416 jiffies! g85517 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:27224 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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 33 21 1c 00 f3 0f 1e fa fb f4 c8 e6 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: 5f01a882fe666d00 RBX: ffffffff8196bc07 RCX: 5f01a882fe666d00 RDX: 0000000000000001 RSI: ffffffff8d7e8390 RDI: ffffffff8bc076e0 RBP: ffffc90000197f10 R08: ffff8880b8732fdb R09: 1ffff110170e65fb R10: dffffc0000000000 R11: ffffed10170e65fc R12: ffffffff8f9e1170 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff1100385ab58 FS: 0000000000000000(0000) GS:ffff888125e0c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f17f2a4f720 CR3: 00000000334b0000 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:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147