syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P141/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=12541, q=791 ncpus=2)
task:kworker/u8:5    state:R  running task     stack:21888 pid:141   tgid:141   ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 <TASK>
 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:lock_release+0x2a6/0x3b0 kernel/locking/lockdep.c:5893
Code: 4d 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 52 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 2a 0f 01 11 <48> 3b 44 24 28 75 75 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d e9
RSP: 0018:ffffc90002ef6f50 EFLAGS: 00000206
RAX: 1c444a3076aa2400 RBX: 0000000000000202 RCX: 1c444a3076aa2400
RDX: 0000000000000003 RSI: ffffffff8db7ed49 RDI: ffffffff8be07960
RBP: ffff88801db0e728 R08: ffffc90002ef7850 R09: 0000000000000000
R10: ffffc90002ef70d8 R11: fffff520005dee1d R12: 0000000000000003
R13: 0000000000000003 R14: ffffffff8e13f2e0 R15: ffff88801db0db80
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:897 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0x1ab1/0x23d0 arch/x86/kernel/unwind_orc.c:695
 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
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6674 [inline]
 kmem_cache_free+0x197/0x620 mm/slub.c:6785
 netlink_broadcast_filtered+0xec7/0x1000 net/netlink/af_netlink.c:1535
 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
 nlmsg_multicast include/net/netlink.h:1184 [inline]
 nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2593
 inet6_ifa_notify net/ipv6/addrconf.c:5621 [inline]
 __ipv6_ifa_notify+0x226/0xaa0 net/ipv6/addrconf.c:6270
 ipv6_ifa_notify net/ipv6/addrconf.c:6322 [inline]
 addrconf_dad_completed+0x180/0xd60 net/ipv6/addrconf.c:4320
 addrconf_dad_work+0xc36/0x14b0 net/ipv6/addrconf.c:-1
 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279
 process_scheduled_works kernel/workqueue.c:3362 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443
 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
 </TASK>
rcu: rcu_preempt kthread starved for 10553 jiffies! g12541 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:27728 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 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
 </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: 6152 Comm: syz-executor886 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:entry_SYSCALL_64+0xf/0x2b arch/x86/entry/entry_64.S:95
Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc f3 0f 1e fa 0f 01 f8 65 48 89 25 85 3f 9e 11 <66> 90 0f 20 dc 0f 1f 44 00 00 48 81 e4 ff e7 ff ff 0f 22 dc 65 48
RSP: 0018:00007f2e3e0aeb88 EFLAGS: 00000002
RAX: 0000000000000027 RBX: 00007f2e3e0aecf0 RCX: 00007f2e3e102077
RDX: 00007f2e3e0aebc0 RSI: 00007f2e3e0aecf0 RDI: 0000000000000021
RBP: 0000000000000000 R08: 00007f2e3e0af6c0 R09: 00007f2e3e0af6c0
R10: 0000000000000000 R11: 0000000000000206 R12: 00007f2e3e1893ec
R13: 000000000000000b R14: 00007ffe2c5fdaa0 R15: 00007ffe2c5fdb88
FS:  00007f2e3e0af6c0(0000) GS:ffff888125c25000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 0000000077946000 CR4: 00000000003526f0
Call Trace: