syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P12741
rcu: 	(detected by 1, t=10502 jiffies, g=49569, q=1101 ncpus=2)
task:syz.1.1784      state:R  running task     stack:26856 pid:12741 tgid:12735 ppid:5810   task_flags:0x400140 flags:0x00080000
Call Trace:
 <IRQ>
 sched_show_task kernel/sched/core.c:7819 [inline]
 sched_show_task+0x423/0x630 kernel/sched/core.c:7794
 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:292 [inline]
 print_other_cpu_stall kernel/rcu/tree_stall.h:681 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:856 [inline]
 rcu_pending kernel/rcu/tree.c:3667 [inline]
 rcu_sched_clock_irq+0x2634/0x31f0 kernel/rcu/tree.c:2704
 update_process_times+0x178/0x2d0 kernel/time/timer.c:2474
 tick_sched_handle kernel/time/tick-sched.c:298 [inline]
 tick_nohz_handler+0x506/0x720 kernel/time/tick-sched.c:319
 __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
 __hrtimer_run_queues+0x64e/0xc40 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x3c0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0x66d/0x20b0 arch/x86/kernel/unwind_orc.c:596
Code: 0f 95 c6 40 84 f7 0f 85 fc 14 00 00 83 e0 07 38 c2 40 0f 9e c6 84 d2 0f 95 c0 40 84 c6 0f 85 e5 14 00 00 4c 0f bf 31 4d 01 fe <0f> b6 41 05 83 e0 07 3c 03 0f 84 bd 08 00 00 3c 04 0f 84 f6 07 00
RSP: 0018:ffffc90004876cc0 EFLAGS: 00000282
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff91b61a56
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffffc90004876d78 R08: ffffffff91b61a5a R09: 00000000f501fefe
R10: 0000000000000002 R11: 00000000000889b3 R12: ffffc90004876d80
R13: ffffc90004876d30 R14: ffffc90004877ac8 R15: ffffc90004877ab8
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6668 [inline]
 kmem_cache_free+0x2d8/0x770 mm/slub.c:6779
 kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1130
 __kfree_skb net/core/skbuff.c:1197 [inline]
 sk_skb_reason_drop+0x136/0x1a0 net/core/skbuff.c:1234
 kfree_skb_reason include/linux/skbuff.h:1322 [inline]
 __netif_receive_skb_core.constprop.0+0x56a/0x35b0 net/core/dev.c:6111
 __netif_receive_skb_list_core+0x355/0x950 net/core/dev.c:6212
 __netif_receive_skb_list net/core/dev.c:6279 [inline]
 netif_receive_skb_list_internal+0x75f/0xdc0 net/core/dev.c:6370
 netif_receive_skb_list net/core/dev.c:6422 [inline]
 netif_receive_skb_list+0x4d/0x460 net/core/dev.c:6412
 xdp_recv_frames net/bpf/test_run.c:269 [inline]
 xdp_test_run_batch.constprop.0+0x17cf/0x1f20 net/bpf/test_run.c:350
 bpf_test_run_xdp_live+0x365/0x770 net/bpf/test_run.c:379
 bpf_prog_test_run_xdp+0xd3d/0x1660 net/bpf/test_run.c:1388
 bpf_prog_test_run kernel/bpf/syscall.c:4703 [inline]
 __sys_bpf+0x1035/0x4980 kernel/bpf/syscall.c:6182
 __do_sys_bpf kernel/bpf/syscall.c:6274 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6272 [inline]
 __x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:6272
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7169d8f749
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:00007f716ac21038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f7169fe6180 RCX: 00007f7169d8f749
RDX: 0000000000000050 RSI: 0000200000000600 RDI: 000000000000000a
RBP: 00007f7169e13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7169fe6218 R14: 00007f7169fe6180 R15: 00007fffde808bc8
 </TASK>
rcu: rcu_preempt kthread starved for 10448 jiffies! g49569 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:28064 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6960
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
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: 0 Comm: swapper/0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: c6 5f 02 c3 cc cc cc cc 0f 1f 00 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 13 49 12 00 fb f4 <e9> cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6
RAX: 0000000002bd7b03 RBX: 0000000000000000 RCX: ffffffff8b7816d9
RDX: 0000000000000000 RSI: ffffffff8dacde18 RDI: ffffffff8bf2b380
RBP: fffffbfff1c12f68 R08: 0000000000000001 R09: ffffed101708673d
R10: ffff8880b84339eb R11: ffffffff8e098670 R12: 0000000000000000
R13: ffffffff8e097b40 R14: ffffffff9088b3d0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3c1867 CR3: 000000002c172000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: fffffffffffffffc DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x38d/0x510 kernel/sched/idle.c:332
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
 rest_init+0x16b/0x2b0 init/main.c:757
 start_kernel+0x3ef/0x4d0 init/main.c:1206
 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x148
 </TASK>