rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6204/1:b..l rcu: (detected by 1, t=10502 jiffies, g=14445, q=690 ncpus=2) task:syz-executor state:R running task stack:21376 pid:6204 tgid:6204 ppid:6197 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:memset_orig+0x15/0xb0 arch/x86/lib/memset_64.S:57 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01 48 0f af c1 <41> 89 f9 41 83 e1 07 75 74 48 89 d1 48 c1 e9 06 74 39 66 0f 1f 84 RSP: 0018:ffffc9000bb6e430 EFLAGS: 00000206 RAX: 0000000000000000 RBX: ffffc9000bb6e540 RCX: 0000000000000000 RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc9000bb6e558 RBP: dffffc0000000000 R08: ffffc9000bb6e567 R09: 1ffff9200176dcac R10: ffffc9000bb6e558 R11: fffff5200176dcad R12: ffffc9000bb6e558 R13: 1ffff9200176dca3 R14: ffffc9000bb6e508 R15: ffffc9000bb6e550 unwind_next_frame+0xeae/0x23d0 arch/x86/kernel/unwind_orc.c:607 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4953 [inline] slab_alloc_node mm/slub.c:5267 [inline] kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5274 __kernfs_new_node+0xdc/0x880 fs/kernfs/dir.c:637 kernfs_new_node+0x102/0x210 fs/kernfs/dir.c:716 kernfs_create_link+0xa7/0x200 fs/kernfs/symlink.c:39 sysfs_do_create_link_sd+0x83/0x110 fs/sysfs/symlink.c:44 device_add_class_symlinks+0xb6/0x240 drivers/base/core.c:3436 device_add+0x475/0xb80 drivers/base/core.c:3640 netdev_register_kobject+0x178/0x310 net/core/net-sysfs.c:2358 register_netdevice+0x1246/0x1a70 net/core/dev.c:11392 veth_newlink+0x5d4/0xa60 drivers/net/veth.c:1885 rtnl_newlink_create+0x310/0xb00 net/core/rtnetlink.c:3840 __rtnl_newlink net/core/rtnetlink.c:3957 [inline] rtnl_newlink+0x16e7/0x1c90 net/core/rtnetlink.c:4072 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737 __sock_sendmsg net/socket.c:752 [inline] __sys_sendto+0x3ce/0x540 net/socket.c:2221 __do_sys_sendto net/socket.c:2228 [inline] __se_sys_sendto net/socket.c:2224 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2224 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f30983915dc RSP: 002b:00007ffc819de010 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f3099114620 RCX: 00007f30983915dc RDX: 0000000000000064 RSI: 00007f3099114670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffc819de064 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f3099114670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10563 jiffies! g14445 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:27576 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 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+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 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 10/25/2025 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 9e 2a 00 f3 0f 1e fa fb f4 48 ee 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: be9062fa95450200 RBX: ffffffff819786ba RCX: be9062fa95450200 RDX: 0000000000000001 RSI: ffffffff8d997e54 RDI: ffffffff8be07960 RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8fa22f70 R13: 1ffff11003ad4b70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000007640e000 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:191 [inline] do_idle+0x1ea/0x520 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147