Port setup goes over stack size on debug illumos bits

[FelixMcFelix]

As in the title. This appears to be occurring on v0.37.402. This corresponds to 6a5d3f3, which just predates rustc v1.89.

[citrus-it]

Here's a stack trace annotated to the left with stack size changes per frame.

BRM15250001 # mdb 1
Loading modules: [ unix genunix specfs dtrace mac cpu.generic apix cpc crypto mm random smbios zfs sata ip hook neti sockfs lofs vmm scsi_vhci arp ufs ipcc logindmux nsmb ptm ]
> $G
C++ symbol demangling enabled
> $C -s
       fffffe015558f080 tr_pftrap+0x12()
[  80] fffffe015558f100 vmem_alloc+0x1b6(fffffffffc520940, 9000, 400)
[  50] fffffe015558f150 kmem_firewall_va_alloc+0x43(fffffffffc520940, 8000, 0)
[ 120] fffffe015558f270 vmem_xalloc+0x569(fffffef40dc07000, 8000, 1000, 0, 0, 0)
[  80] fffffe015558f2f0 vmem_alloc+0x151(fffffef40dc07000, 8000, 0)
[  a0] fffffe015558f390 segkmem_xalloc+0x1aa(fffffef40dc07000, 0, 8000, 0, 0, fffffffffbcf43f0)
[  70] fffffe015558f400 segkmem_alloc_vn+0x4e(fffffef40dc07000, 8000, 0, fffffffffc50b500)
[  30] fffffe015558f430 segkmem_alloc+0x20(fffffef40dc07000, 8000, 0)
[ 120] fffffe015558f550 vmem_xalloc+0x569(fffffef40dc08000, 8000, 1000, 0, 0, 0)
[  80] fffffe015558f5d0 vmem_alloc+0x151(fffffef40dc08000, 8000, 0)
[  90] fffffe015558f660 kmem_slab_create+0x8f(fffffef40dd25008, 0)
[  70] fffffe015558f6d0 kmem_slab_alloc+0x18a(fffffef40dd25008, 0)
[  50] fffffe015558f720 kmem_cache_alloc+0x163(fffffef40dd25008, 0)
[  40] fffffe015558f760 kmem_alloc+0x4a(8000, 0)
[  60] fffffe015558f7c0 <xde::KmemAlloc as core::alloc::global::GlobalAlloc>::alloc::hcf3074bd2d9a650f+0x38()
[  20] fffffe015558f7e0 __rustc::__rust_alloc+0x2b()
[  30] fffffe015558f810 alloc::alloc::alloc::he9640af779642b97+0x37()
[  70] fffffe015558f880 alloc::alloc::Global::alloc_impl::h2e3fdf43edfe7b4b+0x7a()
[  30] fffffe015558f8b0 <alloc::alloc::Global as core::alloc::Allocator>::allocate::hbd07ca0a97d29c0a+0x1b()
[  f0] fffffe015558f9a0 alloc::raw_vec::RawVecInner<A>::try_allocate_in::h9a66dec5be6b41c8+0x1c7()
[  a0] fffffe015558fa40 alloc::raw_vec::RawVecInner<A>::with_capacity_in::hf2273b464df13e49+0x49()
[  20] fffffe015558fa60 alloc::raw_vec::RawVec<T,A>::with_capacity_in::hb6d92e2e71e09879+0x1c()
[  40] fffffe015558faa0 alloc::vec::Vec<T,A>::with_capacity_in::h61ba1aa84b31af1f+0x2f()
[  20] fffffe015558fac0 alloc::vec::Vec<T>::with_capacity::h38eb56467fb736ef+0x18()
[  b0] fffffe015558fb70 <alloc::vec::Vec<T> as alloc::vec::spec_from_iter_nested::SpecFromIterNested<T,I>>::from_iter::hf3a6dd9aa2d7b80f+0x7a()
[  30] fffffe015558fba0 <alloc::vec::Vec<T> as alloc::vec::spec_from_iter::SpecFromIter<T,I>>::from_iter::h04520d94268d4734+0x4f()
[  60] fffffe015558fc00 <alloc::vec::Vec<T> as core::iter::traits::collect::FromIterator<T>>::from_iter::h4e8cdb632fb3433d+0x99()
[  b0] fffffe015558fcb0 core::iter::traits::iterator::Iterator::collect::h191a8af0a673077a+0xe7()
[  d0] fffffe015558fd80 opte::engine::snat::NatPool<T>::add::h2bf41502f848b192+0xba()
[ 100] fffffe015558fe80 opte::engine::snat::SNat<T>::add::h2045021f3b8bb584+0x1a4()
[10c0] fffffe0155590f40 oxide_vpc::engine::nat::setup_ipv4_nat::h46394ceaf8655984+0xfb3()
[ 3c0] fffffe0155591300 oxide_vpc::engine::nat::create_nat_rules::hb55f34e46e0dfead+0xb6()
[ 570] fffffe0155591870 oxide_vpc::engine::nat::setup::he679f6a4604c9fa5+0xf5()
[ c60] fffffe01555924d0 new_port+0x50d()
[ a00] fffffe0155592ed0 create_xde+0x9bd()
[ 6d0] fffffe01555935a0 xde::xde::create_xde_hdlr::hd04a5befa575345d+0x11d()
[ 680] fffffe0155593c20 xde_ioc_opte_cmd+0x472()
[  90] fffffe0155593cb0 xde_ioctl+0x12d()
[  40] fffffe0155593cf0 cdev_ioctl+0x3f(b500020000, de777701, fffffc7fc11face8, 202003, fffffef9a3d1f390, fffffe0155593e08)
[  50] fffffe0155593d40 spec_ioctl+0x55(fffffef975875200, de777701, fffffc7fc11face8, 202003, fffffef9a3d1f390, fffffe0155593e08)
[  90] fffffe0155593dd0 fop_ioctl+0x40(fffffef975875200, de777701, fffffc7fc11face8, 202003, fffffef9a3d1f390, fffffe0155593e08)
[ 120] fffffe0155593ef0 ioctl+0x144(22, de777701, fffffc7fc11face8)
[  10] fffffe0155593f00 sys_syscall+0x283()

The total used stack is

> fffffe0155593f00-fffffe015558f080=X
                4e80

plus the initial frame. Awfully close to the default LWP limit of 0x5000

I'll grab the same stack from non-debug bits for comparison.