rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (5418 ticks this GP) idle=a324/1/0x4000000000000000 softirq=11382/11390 fqs=43
rcu: 	(t=10500 jiffies g=10833 q=703 ncpus=2)
rcu: rcu_preempt kthread starved for 5381 jiffies! g10833 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:26968 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 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
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 5980 Comm: syz.1.34 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa9/0x110 kernel/locking/spinlock.c:194
Code: 74 05 e8 0a d9 1a f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> e2 53 ea f6 65 8b 05 d3 9a 92 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900001f0640 EFLAGS: 00000206
RAX: 4381c08ff7cf9900 RBX: 0000000000000a02 RCX: 4381c08ff7cf9900
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: 0000000000000001
RBP: ffffc900001f06d8 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: dffffc0000000000
R13: ffff888076f5cd00 R14: ffffffff970c4c18 R15: 1ffff9200003e0c8
FS:  00007f11646d26c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d320ff8 CR3: 000000005d8c4000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 __debug_check_no_obj_freed lib/debugobjects.c:999 [inline]
 debug_check_no_obj_freed+0x51f/0x540 lib/debugobjects.c:1020
 slab_free_hook mm/slub.c:1786 [inline]
 slab_free_freelist_hook+0xd2/0x1b0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 kmem_cache_free+0xf8/0x280 mm/slub.c:3852
 skb_kfree_head net/core/skbuff.c:947 [inline]
 skb_free_head net/core/skbuff.c:961 [inline]
 skb_release_data+0x60a/0x800 net/core/skbuff.c:991
 skb_release_all net/core/skbuff.c:1057 [inline]
 __kfree_skb net/core/skbuff.c:1071 [inline]
 kfree_skb_reason+0x10e/0x170 net/core/skbuff.c:1107
 kfree_skb include/linux/skbuff.h:1232 [inline]
 ip6_mc_input+0xa7e/0xc70 net/ipv6/ip6_input.c:589
 NF_HOOK+0x303/0x390 include/linux/netfilter.h:304
 __netif_receive_skb_one_core net/core/dev.c:5608 [inline]
 __netif_receive_skb+0xcc/0x290 net/core/dev.c:5722
 process_backlog+0x380/0x6e0 net/core/dev.c:6050
 __napi_poll+0xc0/0x460 net/core/dev.c:6612
 napi_poll net/core/dev.c:6679 [inline]
 net_rx_action+0x5ea/0xbf0 net/core/dev.c:6815
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:preempt_schedule_irq+0xb0/0x140 kernel/sched/core.c:7009
Code: 44 24 20 f6 44 24 21 02 74 0b 0f 0b 48 f7 03 08 00 00 00 74 63 bf 01 00 00 00 e8 8b b3 eb f6 e8 26 3a 1c f7 fb bf 01 00 00 00 <e8> db b5 ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24
RSP: 0018:ffffc90004f07c60 EFLAGS: 00000286
RAX: 4381c08ff7cf9900 RBX: 0000000000000000 RCX: 4381c08ff7cf9900
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: 0000000000000001
RBP: ffffc90004f07d10 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff920009e0f8c
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:udp_init_sock+0x0/0x1d0 net/ipv4/udp.c:1601
Code: ff ff 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c 1d ff ff ff 4c 89 e7 e8 4f 11 e8 f8 e9 10 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 <f3> 0f 1e fa 55 41 57 41 56 41 55 41 54 53 48 89 fb 49 bf 00 00 00
RSP: 0018:ffffc90004f07dd0 EFLAGS: 00000286
RAX: ffffffff88f4ed50 RBX: ffffffff8e0820d0 RCX: dffffc0000000000
RDX: ffffc9000d3cb000 RSI: 0000000000009082 RDI: ffff88814dec5e40
RBP: ffff88814dec5e40 R08: ffff88814dec6367 R09: 1ffff11029bd8c6c
R10: dffffc0000000000 R11: ffffed1029bd8c6d R12: 1ffff11029bd8bcd
R13: ffff88814dec5e40 R14: ffff88814dec5e68 R15: ffff888077e20600
 inet_create+0xcf7/0xfe0 net/ipv4/af_inet.c:383
 __sock_create+0x4a6/0x940 net/socket.c:1571
 sock_create net/socket.c:1627 [inline]
 __sys_socket_create net/socket.c:1664 [inline]
 __sys_socket+0xd7/0x1a0 net/socket.c:1715
 __do_sys_socket net/socket.c:1729 [inline]
 __se_sys_socket net/socket.c:1727 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1727
 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: 0033:0x7f116378f749
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:00007f11646d2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007f11639e5fa0 RCX: 00007f116378f749
RDX: 0000000000000000 RSI: 1000000000000002 RDI: 0000000000000002
RBP: 00007f1163813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f11639e6038 R14: 00007f11639e5fa0 R15: 00007ffe641d07b8
 </TASK>
CPU: 1 PID: 5980 Comm: syz.1.34 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa9/0x110 kernel/locking/spinlock.c:194
Code: 74 05 e8 0a d9 1a f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> e2 53 ea f6 65 8b 05 d3 9a 92 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900001f0640 EFLAGS: 00000206
RAX: 4381c08ff7cf9900 RBX: 0000000000000a02 RCX: 4381c08ff7cf9900
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: 0000000000000001
RBP: ffffc900001f06d8 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: dffffc0000000000
R13: ffff888076f5cd00 R14: ffffffff970c4c18 R15: 1ffff9200003e0c8
FS:  00007f11646d26c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d320ff8 CR3: 000000005d8c4000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 __debug_check_no_obj_freed lib/debugobjects.c:999 [inline]
 debug_check_no_obj_freed+0x51f/0x540 lib/debugobjects.c:1020
 slab_free_hook mm/slub.c:1786 [inline]
 slab_free_freelist_hook+0xd2/0x1b0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 kmem_cache_free+0xf8/0x280 mm/slub.c:3852
 skb_kfree_head net/core/skbuff.c:947 [inline]
 skb_free_head net/core/skbuff.c:961 [inline]
 skb_release_data+0x60a/0x800 net/core/skbuff.c:991
 skb_release_all net/core/skbuff.c:1057 [inline]
 __kfree_skb net/core/skbuff.c:1071 [inline]
 kfree_skb_reason+0x10e/0x170 net/core/skbuff.c:1107
 kfree_skb include/linux/skbuff.h:1232 [inline]
 ip6_mc_input+0xa7e/0xc70 net/ipv6/ip6_input.c:589
 NF_HOOK+0x303/0x390 include/linux/netfilter.h:304
 __netif_receive_skb_one_core net/core/dev.c:5608 [inline]
 __netif_receive_skb+0xcc/0x290 net/core/dev.c:5722
 process_backlog+0x380/0x6e0 net/core/dev.c:6050
 __napi_poll+0xc0/0x460 net/core/dev.c:6612
 napi_poll net/core/dev.c:6679 [inline]
 net_rx_action+0x5ea/0xbf0 net/core/dev.c:6815
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:preempt_schedule_irq+0xb0/0x140 kernel/sched/core.c:7009
Code: 44 24 20 f6 44 24 21 02 74 0b 0f 0b 48 f7 03 08 00 00 00 74 63 bf 01 00 00 00 e8 8b b3 eb f6 e8 26 3a 1c f7 fb bf 01 00 00 00 <e8> db b5 ff ff 48 c7 44 24 40 00 00 00 00 9c 8f 44 24 40 8b 44 24
RSP: 0018:ffffc90004f07c60 EFLAGS: 00000286
RAX: 4381c08ff7cf9900 RBX: 0000000000000000 RCX: 4381c08ff7cf9900
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: 0000000000000001
RBP: ffffc90004f07d10 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff920009e0f8c
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:udp_init_sock+0x0/0x1d0 net/ipv4/udp.c:1601
Code: ff ff 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c 1d ff ff ff 4c 89 e7 e8 4f 11 e8 f8 e9 10 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 <f3> 0f 1e fa 55 41 57 41 56 41 55 41 54 53 48 89 fb 49 bf 00 00 00
RSP: 0018:ffffc90004f07dd0 EFLAGS: 00000286
RAX: ffffffff88f4ed50 RBX: ffffffff8e0820d0 RCX: dffffc0000000000
RDX: ffffc9000d3cb000 RSI: 0000000000009082 RDI: ffff88814dec5e40
RBP: ffff88814dec5e40 R08: ffff88814dec6367 R09: 1ffff11029bd8c6c
R10: dffffc0000000000 R11: ffffed1029bd8c6d R12: 1ffff11029bd8bcd
R13: ffff88814dec5e40 R14: ffff88814dec5e68 R15: ffff888077e20600
 inet_create+0xcf7/0xfe0 net/ipv4/af_inet.c:383
 __sock_create+0x4a6/0x940 net/socket.c:1571
 sock_create net/socket.c:1627 [inline]
 __sys_socket_create net/socket.c:1664 [inline]
 __sys_socket+0xd7/0x1a0 net/socket.c:1715
 __do_sys_socket net/socket.c:1729 [inline]
 __se_sys_socket net/socket.c:1727 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1727
 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: 0033:0x7f116378f749
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:00007f11646d2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007f11639e5fa0 RCX: 00007f116378f749
RDX: 0000000000000000 RSI: 1000000000000002 RDI: 0000000000000002
RBP: 00007f1163813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f11639e6038 R14: 00007f11639e5fa0 R15: 00007ffe641d07b8
 </TASK>