syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P16343/3:b..l
	(detected by 0, t=10502 jiffies, g=101213, q=122 ncpus=2)
task:syz.1.2972      state:R  running task     stack:24480 pid:16343 ppid:7676   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_acquire+0x20f/0x490 kernel/locking/lockdep.c:5666
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc900034b6ae0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: d1ca05e152598a00
RDX: 0000000000000000 RSI: ffffffff8a6c1180 RDI: ffffffff8abf1260
RBP: ffffc900034b6bf8 R08: dffffc0000000000 R09: fffffbfff2117049
R10: fffffbfff2117049 R11: 1ffffffff2117048 R12: 0000000000000000
R13: 1ffff92000696d68 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 sk_filter_trim_cap+0x178/0x900 net/core/filter.c:149
 sk_filter include/linux/filter.h:881 [inline]
 do_one_broadcast net/netlink/af_netlink.c:1458 [inline]
 netlink_broadcast+0x6c8/0x10f0 net/netlink/af_netlink.c:1506
 nlmsg_multicast include/net/netlink.h:1071 [inline]
 xfrm_nlmsg_multicast+0x17c/0x1e0 net/xfrm/xfrm_user.c:1332
 xfrm_send_acquire+0x946/0xf60 net/xfrm/xfrm_user.c:3427
 km_query+0x10e/0x200 net/xfrm/xfrm_state.c:2248
 xfrm_state_find+0x1fd2/0x2bd0 net/xfrm/xfrm_state.c:1165
 xfrm_tmpl_resolve_one net/xfrm/xfrm_policy.c:2421 [inline]
 xfrm_tmpl_resolve net/xfrm/xfrm_policy.c:2466 [inline]
 xfrm_resolve_and_create_bundle+0x731/0x2c40 net/xfrm/xfrm_policy.c:2759
 xfrm_lookup_with_ifid+0x26a/0x1ff0 net/xfrm/xfrm_policy.c:3093
 xfrm_lookup net/xfrm/xfrm_policy.c:3222 [inline]
 xfrm_lookup_route+0x38/0x1b0 net/xfrm/xfrm_policy.c:3233
 rawv6_sendmsg+0xc55/0x1730 net/ipv6/raw.c:896
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x59b/0x970 net/socket.c:2519
 ___sys_sendmsg+0x21c/0x290 net/socket.c:2573
 __sys_sendmmsg+0x272/0x490 net/socket.c:2659
 __do_sys_sendmmsg net/socket.c:2688 [inline]
 __se_sys_sendmmsg net/socket.c:2685 [inline]
 __x64_sys_sendmmsg+0x9c/0xb0 net/socket.c:2685
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f389698e969
RSP: 002b:00007f38978b3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f3896bb6080 RCX: 00007f389698e969
RDX: 00000000000002e9 RSI: 0000200000000480 RDI: 0000000000000008
RBP: 00007f3896a10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f3896bb6080 R15: 00007ffd3ea995c8
 </TASK>
rcu: rcu_preempt kthread starved for 10522 jiffies! g101213 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26144 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730
 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock_irqrestore+0xf6/0x100 kernel/locking/spinlock.c:194
 __mod_timer+0x8ee/0xd20 kernel/time/timer.c:1118
 schedule_timeout+0x157/0x280 kernel/time/timer.c:1964
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.140-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:736
Code: 48 89 df e8 e7 30 b9 f7 e9 4c ff ff ff e8 4d 14 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d d7 82 4d 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8c607d88 EFLAGS: 000002c6
RAX: a63e62f244431f00 RBX: ffffffff8a1920b7 RCX: a63e62f244431f00
RDX: 0000000000000001 RSI: ffffffff8a6c0000 RDI: ffffffff8abf1260
RBP: ffffffff8c607ec0 R08: dffffc0000000000 R09: ffffed10171c6aee
R10: ffffed10171c6aee R11: 1ffff110171c6aed R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff8c6bc680 R15: 1ffffffff1bfd046
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f91eff8 CR3: 0000000061fec000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x1fc/0x570 kernel/sched/idle.c:303
 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:401
 rest_init+0x2dc/0x300 init/main.c:733
 arch_call_rest_init+0xa/0xa init/main.c:893
 start_kernel+0x490/0x539 init/main.c:1140
 secondary_startup_64_no_verify+0xcf/0xdb
 </TASK>