rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4408/1:b..l
	(detected by 1, t=10502 jiffies, g=10241, q=114 ncpus=2)
task:syz.0.1         state:R  running task     stack:24320 pid:4408  ppid:4265   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 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_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696
RIP: 0010:__sanitizer_cov_trace_switch+0x4/0xe0 kernel/kcov.c:332
Code: 77 1e 49 ff c0 4c 89 02 48 c7 44 0a 08 07 00 00 00 48 89 7c 0a 10 48 89 74 0a 18 48 89 44 0a 20 c3 0f 1f 44 00 00 48 8b 4e 08 <48> 83 c1 f8 48 c1 c1 3d 48 83 f9 07 0f 87 c1 00 00 00 b8 8b 00 00
RSP: 0018:ffffc90004c5f368 EFLAGS: 00000282
RAX: 0000000000000001 RBX: ffff888074e11c10 RCX: 0000000000000008
RDX: ffffc9000eaca000 RSI: ffffffff8dda5d00 RDI: 0000000000000001
RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff215ba49
R10: fffffbfff215ba49 R11: 1ffffffff215ba48 R12: 0000000000000000
R13: ffff888074e11c08 R14: 0000000000000001 R15: ffffc90004c5f420
 nf_hook_slow+0xce/0x200 net/netfilter/core.c:615
 nf_hook+0x211/0x370 include/linux/netfilter.h:257
 __ip_local_out+0x49c/0x5d0 net/ipv4/ip_output.c:115
 ip_local_out net/ipv4/ip_output.c:124 [inline]
 ip_send_skb+0x48/0x1c0 net/ipv4/ip_output.c:1600
 udp_send_skb+0xa88/0x1580 net/ipv4/udp.c:993
 udp_sendmsg+0x1b0c/0x2390 net/ipv4/udp.c:1281
 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: 0033:0x7f284398ebe9
RSP: 002b:00007f2844898038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f2843bb6090 RCX: 00007f284398ebe9
RDX: 0000000000000300 RSI: 0000200000004d00 RDI: 0000000000000005
RBP: 00007f2843a11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000f00 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2843bb6128 R14: 00007f2843bb6090 R15: 00007ffc9b503268
 </TASK>
rcu: rcu_preempt kthread starved for 10527 jiffies! g10241 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:27040 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
 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: 1 PID: 0 Comm: swapper/1 Not tainted 6.1.147-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:742
Code: 48 89 df e8 c7 c9 b0 f7 e9 4c ff ff ff e8 ed 07 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d 67 85 66 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:ffffc90000177de8 EFLAGS: 000002c6
RAX: c77a2d19aafb3a00 RBX: ffffffff8a201e87 RCX: c77a2d19aafb3a00
RDX: 0000000000000001 RSI: ffffffff8a8c0460 RDI: ffffffff8adef320
RBP: ffffc90000177f20 R08: dffffc0000000000 R09: ffffed10171e6af6
R10: ffffed10171e6af6 R11: 1ffff110171e6af5 R12: 0000000000000001
R13: dffffc0000000000 R14: ffff888017739dc0 R15: 1ffffffff1c3e9b6
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000001d000 CR3: 000000007c782000 CR4: 00000000003506e0
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
 start_secondary+0xe4/0xf0 arch/x86/kernel/smpboot.c:281
 secondary_startup_64_no_verify+0xcf/0xdb
 </TASK>