In the Linux kernel, the following vulnerability has been resolved:

iommu/vt-d: Don't issue ATS Invalidation request when device is disconnected

For those endpoint devices connect to system via hotplug capable ports,
users could request a hot reset to the device by flapping device's link
through setting the slot's link control register, as pciehp_ist() DLLSC
interrupt sequence response, pciehp will unload the device driver and
then power it off. thus cause an IOMMU device-TLB invalidation (Intel
VT-d spec, or ATS Invalidation in PCIe spec r6.1) request for non-existence
target device to be sent and deadly loop to retry that request after ITE
fault triggered in interrupt context.

That would cause following continuous hard lockup warning and system hang

[ 4211.433662] pcieport 0000:17:01.0: pciehp: Slot(108): Link Down
[ 4211.433664] pcieport 0000:17:01.0: pciehp: Slot(108): Card not present
[ 4223.822591] NMI watchdog: Watchdog detected hard LOCKUP on cpu 144
[ 4223.822622] CPU: 144 PID: 1422 Comm: irq/57-pciehp Kdump: loaded Tainted: G S
         OE    kernel version xxxx
[ 4223.822623] Hardware name: vendorname xxxx 666-106,
BIOS 01.01.02.03.01 05/15/2023
[ 4223.822623] RIP: 0010:qi_submit_sync+0x2c0/0x490
[ 4223.822624] Code: 48 be 00 00 00 00 00 08 00 00 49 85 74 24 20 0f 95 c1 48 8b
 57 10 83 c1 04 83 3c 1a 03 0f 84 a2 01 00 00 49 8b 04 24 8b 70 34 <40> f6 c6 1
0 74 17 49 8b 04 24 8b 80 80 00 00 00 89 c2 d3 fa 41 39
[ 4223.822624] RSP: 0018:ffffc4f074f0bbb8 EFLAGS: 00000093
[ 4223.822625] RAX: ffffc4f040059000 RBX: 0000000000000014 RCX: 0000000000000005
[ 4223.822625] RDX: ffff9f3841315800 RSI: 0000000000000000 RDI: ffff9f38401a8340
[ 4223.822625] RBP: ffff9f38401a8340 R08: ffffc4f074f0bc00 R09: 0000000000000000
[ 4223.822626] R10: 0000000000000010 R11: 0000000000000018 R12: ffff9f384005e200
[ 4223.822626] R13: 0000000000000004 R14: 0000000000000046 R15: 0000000000000004
[ 4223.822626] FS:  0000000000000000(0000) GS:ffffa237ae400000(0000)
knlGS:0000000000000000
[ 4223.822627] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4223.822627] CR2: 00007ffe86515d80 CR3: 000002fd3000a001 CR4: 0000000000770ee0
[ 4223.822627] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 4223.822628] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
[ 4223.822628] PKRU: 55555554
[ 4223.822628] Call Trace:
[ 4223.822628]  qi_flush_dev_iotlb+0xb1/0xd0
[ 4223.822628]  __dmar_remove_one_dev_info+0x224/0x250
[ 4223.822629]  dmar_remove_one_dev_info+0x3e/0x50
[ 4223.822629]  intel_iommu_release_device+0x1f/0x30
[ 4223.822629]  iommu_release_device+0x33/0x60
[ 4223.822629]  iommu_bus_notifier+0x7f/0x90
[ 4223.822630]  blocking_notifier_call_chain+0x60/0x90
[ 4223.822630]  device_del+0x2e5/0x420
[ 4223.822630]  pci_remove_bus_device+0x70/0x110
[ 4223.822630]  pciehp_unconfigure_device+0x7c/0x130
[ 4223.822631]  pciehp_disable_slot+0x6b/0x100
[ 4223.822631]  pciehp_handle_presence_or_link_change+0xd8/0x320
[ 4223.822631]  pciehp_ist+0x176/0x180
[ 4223.822631]  ? irq_finalize_oneshot.part.50+0x110/0x110
[ 4223.822632]  irq_thread_fn+0x19/0x50
[ 4223.822632]  irq_thread+0x104/0x190
[ 4223.822632]  ? irq_forced_thread_fn+0x90/0x90
[ 4223.822632]  ? irq_thread_check_affinity+0xe0/0xe0
[ 4223.822633]  kthread+0x114/0x130
[ 4223.822633]  ? __kthread_cancel_work+0x40/0x40
[ 4223.822633]  ret_from_fork+0x1f/0x30
[ 4223.822633] Kernel panic - not syncing: Hard LOCKUP
[ 4223.822634] CPU: 144 PID: 1422 Comm: irq/57-pciehp Kdump: loaded Tainted: G S
         OE     kernel version xxxx
[ 4223.822634] Hardware name: vendorname xxxx 666-106,
BIOS 01.01.02.03.01 05/15/2023
[ 4223.822634] Call Trace:
[ 4223.822634]  <NMI>
[ 4223.822635]  dump_stack+0x6d/0x88
[ 4223.822635]  panic+0x101/0x2d0
[ 4223.822635]  ? ret_from_fork+0x11/0x30
[ 4223.822635]  nmi_panic.cold.14+0xc/0xc
[ 4223.822636]  watchdog_overflow_callback.cold.8+0x6d/0x81
[ 4223.822636]  __perf_event_overflow+0x4f/0xf0
[ 4223.822636]  handle_pmi_common
---truncated---

kernel.org https://git.kernel.org/stable/c/025bc6b41e020aeb1e71f84ae3ffce945026de05 [No types assigned]

kernel.org https://git.kernel.org/stable/c/2b74b2a92e524d7c8dec8e02e95ecf18b667c062 [No types assigned]

kernel.org https://git.kernel.org/stable/c/34a7b30f56d30114bf4d436e4dc793afe326fbcf [No types assigned]

kernel.org https://git.kernel.org/stable/c/4fc82cd907ac075648789cc3a00877778aa1838b [No types assigned]

kernel.org https://git.kernel.org/stable/c/c04f2780919f20e2cc4846764221f5e802555868 [No types assigned]

kernel.org https://git.kernel.org/stable/c/d70f1c85113cd8c2aa8373f491ca5d1b22ec0554 [No types assigned]

kernel.org https://git.kernel.org/stable/c/f873b85ec762c5a6abe94a7ddb31df5d3ba07d85 [No types assigned]