rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5908/1:b..l rcu: (detected by 0, t=10503 jiffies, g=10661, q=664 ncpus=2) task:syz-executor state:R running task stack:21352 pid:5908 ppid:5904 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_notrace+0xce/0x110 kernel/sched/core.c:6959 preempt_schedule_notrace_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:46 rcu_is_watching+0x7a/0xb0 kernel/rcu/tree.c:701 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0xcb/0x410 kernel/locking/lockdep.c:5725 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] is_bpf_text_address+0x47/0x2a0 kernel/bpf/core.c:741 kernel_text_address+0xa0/0xd0 kernel/extable.c:125 __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:52 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3519 leaf_new net/ipv4/fib_trie.c:358 [inline] fib_insert_node net/ipv4/fib_trie.c:1114 [inline] fib_insert_alias+0x13b/0x1210 net/ipv4/fib_trie.c:1164 fib_table_insert+0x67d/0x1b50 net/ipv4/fib_trie.c:1359 fib_magic+0x2c5/0x390 net/ipv4/fib_frontend.c:1118 fib_add_ifaddr+0x144/0x5e0 net/ipv4/fib_frontend.c:1140 fib_inetaddr_event+0x140/0x1d0 net/ipv4/fib_frontend.c:1454 notifier_call_chain+0x197/0x390 kernel/notifier.c:93 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:388 __inet_insert_ifa+0x9ae/0xbb0 net/ipv4/devinet.c:570 inet_rtm_newaddr+0x1014/0x1a00 net/ipv4/devinet.c:986 rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6472 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2545 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x751/0x8d0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] __sys_sendto+0x46a/0x620 net/socket.c:2201 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0xf0 net/socket.c:2209 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f6d111915dc RSP: 002b:00007ffdd72b1570 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f6d11f14620 RCX: 00007f6d111915dc RDX: 0000000000000028 RSI: 00007f6d11f14670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffdd72b15c4 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f6d11f14670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10566 jiffies! g10661 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:27088 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_timeout+0x160/0x280 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 6191 Comm: syz.1.104 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00 RSP: 0018:ffffc900051b7780 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 3391c21126a5a500 RDX: 0000000000000000 RSI: ffffffff8aaace60 RDI: ffffffff8afc6f80 RBP: ffffc900051b7890 R08: dffffc0000000000 R09: 1ffffffff21b52a6 R10: dffffc0000000000 R11: fffffbfff21b52a7 R12: 1ffff92000a36efc R13: ffff8880303ab120 R14: 0000000000000246 R15: dffffc0000000000 FS: 00007f5848f986c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000007bf9e000 CR4: 00000000003506f0 Call Trace: __might_fault+0xc6/0x120 mm/memory.c:5968 __clear_user arch/x86/include/asm/uaccess_64.h:167 [inline] copy_fpstate_to_sigframe+0x13c/0xbe0 arch/x86/kernel/fpu/signal.c:216 get_sigframe+0x5ce/0x7c0 arch/x86/kernel/signal.c:142 x64_setup_rt_frame+0x158/0xcd0 arch/x86/kernel/signal_64.c:175 setup_rt_frame arch/x86/kernel/signal.c:223 [inline] handle_signal arch/x86/kernel/signal.c:267 [inline] arch_do_signal_or_restart+0x3fa/0x7b0 arch/x86/kernel/signal.c:312 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f584818f749 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f5848f980e8 EFLAGS: 00000246 RAX: 0000000000000001 RBX: 00007f58483e5fa8 RCX: 00007f584818f749 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f58483e5fac RBP: 00007f58483e5fa0 R08: 0000000000745a85 R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f58483e6038 R14: 00007ffe5f67a820 R15: 00007ffe5f67a908 sched: RT throttling activated