rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=4d94/1/0x4000000000000000 softirq=87312/87313 fqs=4
rcu: 	(detected by 0, t=10506 jiffies, g=63245, q=451 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 19226 Comm: syz.0.3363 Not tainted 6.16.0-rc3-syzkaller-00072-gee88bddf7f2f #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:hlock_class+0x4/0x70 kernel/locking/lockdep.c:229
Code: 0f 0b 90 e9 01 ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f b7 47 20 <66> 25 ff 1f 0f b7 c0 48 0f a3 05 3d 9b 3b 14 73 15 48 8d 04 80 48
RSP: 0018:ffffc90000a08c38 EFLAGS: 00000046
RAX: 0000000000004c9b RBX: 61c8864680b583eb RCX: 00000000fcd41028
RDX: a8d35bb04e02924a RSI: 0000000005e22bf8 RDI: ffff88801c7c5398
RBP: ffff88801c7c4880 R08: a8d35bb04e02924a R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88801c7c5370
R13: ffff88801c7c5398 R14: 00000000b4b0719a R15: 0000000000000003
FS:  00007f3f8fe3c6c0(0000) GS:ffff888124852000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000200030 CR3: 0000000034003000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 lookup_chain_cache_add kernel/locking/lockdep.c:3823 [inline]
 validate_chain kernel/locking/lockdep.c:3879 [inline]
 __lock_acquire+0xb8a/0x1c90 kernel/locking/lockdep.c:5240
 lock_acquire kernel/locking/lockdep.c:5871 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 advance_sched+0xd9/0xc80 net/sched/sch_taprio.c:924
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x202/0xad0 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 36 50 15 f6 48 89 df e8 1e a4 15 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 <bf> 01 00 00 00 e8 55 c4 05 f6 65 8b 05 4e ba 49 08 85 c0 74 16 5b
RSP: 0018:ffffc900043ef770 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffff88807e192a40 RCX: 0000000000000006
RDX: 0000000000000000 RSI: ffffffff8de19fc6 RDI: ffffffff8c157ba0
RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90a81257 R11: 0000000000000001 R12: ffff8880565ba140
R13: 0000000000000246 R14: ffff88807e192a28 R15: ffffc900043ef8f8
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 __skb_try_recv_datagram+0x172/0x4f0 net/core/datagram.c:267
 __unix_dgram_recvmsg+0x1bd/0xc50 net/unix/af_unix.c:2503
 unix_dgram_recvmsg+0xd0/0x110 net/unix/af_unix.c:2605
 sock_recvmsg_nosec net/socket.c:1017 [inline]
 ____sys_recvmsg+0x5f6/0x6b0 net/socket.c:2784
 ___sys_recvmsg+0x114/0x1a0 net/socket.c:2828
 do_recvmmsg+0x2fe/0x750 net/socket.c:2923
 __sys_recvmmsg net/socket.c:2997 [inline]
 __do_sys_recvmmsg net/socket.c:3020 [inline]
 __se_sys_recvmmsg net/socket.c:3013 [inline]
 __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3013
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3f8ef8e929
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:00007f3f8fe3c038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f3f8f1b6080 RCX: 00007f3f8ef8e929
RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004
RBP: 00007f3f8f010b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f3f8f1b6080 R15: 00007ffe09f055b8
 </TASK>
rcu: rcu_preempt kthread starved for 7655 jiffies! g63245 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:27784 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6878
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 5479 Comm: dhcpcd Not tainted 6.16.0-rc3-syzkaller-00072-gee88bddf7f2f #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:write_comp_data+0x8b/0x90 kernel/kcov.c:272
Code: 00 00 4a 8d 34 dd 28 00 00 00 48 39 f2 72 1b 48 83 c7 01 48 89 38 4c 89 44 30 e0 4c 89 4c 30 e8 4c 89 54 30 f0 4a 89 4c d8 20 <c3> cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3
RSP: 0018:ffffc90003247748 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b853fe20 RCX: ffffffff81b001cd
RDX: ffff8880326f0000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000
R13: 0000000000000003 R14: ffffed10170a7fc5 R15: ffff8880b843b580
FS:  00007f357c113740(0000) GS:ffff888124752000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31e1cff8 CR3: 000000007b5aa000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 csd_lock_wait kernel/smp.c:340 [inline]
 smp_call_function_many_cond+0xd9d/0x1510 kernel/smp.c:885
 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
 flush_tlb_mm_range+0x4a0/0x1790 arch/x86/mm/tlb.c:1451
 dup_mmap+0xfa2/0x21d0 mm/mmap.c:1877
 dup_mm kernel/fork.c:1477 [inline]
 copy_mm kernel/fork.c:1529 [inline]
 copy_process+0x4081/0x76a0 kernel/fork.c:2169
 kernel_clone+0xfc/0x960 kernel/fork.c:2599
 __do_sys_clone+0xce/0x120 kernel/fork.c:2742
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f357c1e7636
Code: 89 df e8 6d e8 f6 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 52 89 c5 85 c0 75 31 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffc441cd730 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffc441cd738 RCX: 00007f357c1e7636
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007ffc441edc80 R08: 0000000000000000 R09: 0000000000000001
R10: 00007f357c113a10 R11: 0000000000000246 R12: 00007ffc441cd870
R13: 0000000000000000 R14: 0000000000000000 R15: 0000561397ee2ac0
 </TASK>