rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16963/3:b..l P16880/1:b..l rcu: (detected by 0, t=10502 jiffies, g=87065, q=197 ncpus=2) task:syz-executor state:R running task stack:22568 pid:16880 tgid:16880 ppid:16854 task_flags:0x400140 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:702 RIP: 0010:unwind_next_frame+0xa74/0x2390 arch/x86/kernel/unwind_orc.c:581 Code: 17 00 00 48 89 d8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 99 17 00 00 48 0f bf 02 49 01 c4 48 8d 5e 01 48 8b 44 24 40 0f b6 04 28 <84> c0 0f 85 78 13 00 00 49 89 df 49 c1 ef 03 41 0f b6 04 2f 84 c0 RSP: 0018:ffffc900044264d8 EFLAGS: 00000286 RAX: 0000000000000000 RBX: ffffffff90b1b671 RCX: ffffffff900a69d0 RDX: ffffffff90b1b66c RSI: ffffffff90b1b670 RDI: ffffffff8bc07780 RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff81731d25 R10: dffffc0000000000 R11: ffffffff81abbce0 R12: ffffc90004426d60 R13: ffffc900044265f8 R14: ffffc900044265a8 R15: ffffc900044265e0 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:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __kmalloc_cache_noprof+0x3d5/0x6f0 mm/slub.c:5725 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] ref_tracker_alloc+0x133/0x460 lib/ref_tracker.c:271 __netdev_tracker_alloc include/linux/netdevice.h:4375 [inline] netdev_hold include/linux/netdevice.h:4404 [inline] batadv_hardif_add_interface net/batman-adv/hard-interface.c:878 [inline] batadv_hard_if_event+0xf0f/0x1730 net/batman-adv/hard-interface.c:958 notifier_call_chain+0x1b6/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline] call_netdevice_notifiers net/core/dev.c:2281 [inline] register_netdevice+0x1608/0x1ae0 net/core/dev.c:11332 veth_newlink+0x5d4/0xa60 drivers/net/veth.c:1884 rtnl_newlink_create+0x310/0xb00 net/core/rtnetlink.c:3833 __rtnl_newlink net/core/rtnetlink.c:3950 [inline] rtnl_newlink+0x16e4/0x1c80 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6954 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 __sys_sendto+0x3bd/0x520 net/socket.c:2244 __do_sys_sendto net/socket.c:2251 [inline] __se_sys_sendto net/socket.c:2247 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2247 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: 0033:0x7f44ca390d5c RSP: 002b:00007ffe611c39d0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f44cb114620 RCX: 00007f44ca390d5c RDX: 0000000000000068 RSI: 00007f44cb114670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffe611c3a24 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f44cb114670 R15: 0000000000000000 task:syz.9.2826 state:R running task stack:24168 pid:16963 tgid:16962 ppid:11025 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7113 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7137 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] filemap_map_pages+0x1621/0x1c60 mm/filemap.c:3858 do_fault_around mm/memory.c:5656 [inline] do_read_fault mm/memory.c:5689 [inline] do_fault mm/memory.c:5832 [inline] do_pte_missing mm/memory.c:4361 [inline] handle_pte_fault mm/memory.c:6177 [inline] __handle_mm_fault+0x347e/0x5400 mm/memory.c:6318 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6487 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x165c/0x2a00 mm/gup.c:1428 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1860 __mm_populate+0x24c/0x380 mm/gup.c:1963 mm_populate include/linux/mm.h:3471 [inline] vm_mmap_pgoff+0x387/0x4d0 mm/util.c:585 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: 0033:0x7f550198eec9 RSP: 002b:00007f550285c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f5501be5fa0 RCX: 00007f550198eec9 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007f5501a11f91 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5501be6038 R14: 00007f5501be5fa0 R15: 00007ffdfbb902a8 rcu: rcu_preempt kthread starved for 10399 jiffies! g87065 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:27096 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: 0 UID: 0 PID: 0 Comm: swapper/0 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: 2e e3 c4 f5 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 e3 d0 1c 00 f3 0f 1e fa fb f4 03 e3 c4 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8de07d80 EFLAGS: 000002c6 RAX: de7a2fd1c9883200 RBX: ffffffff81960c17 RCX: de7a2fd1c9883200 RDX: 0000000000000001 RSI: ffffffff8d7e8a1b RDI: ffffffff8bc077e0 RBP: ffffffff8de07ea8 R08: ffff8880b8632fdb R09: 1ffff110170c65fb R10: dffffc0000000000 R11: ffffed10170c65fc R12: ffffffff8f9e1170 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a40 FS: 0000000000000000(0000) GS:ffff888125d0f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f509f0d6000 CR3: 000000005b100000 CR4: 0000000000350ef0 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 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3ae/0x410 init/main.c:1111 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147