In the Linux kernel, the following vulnerability has been resolved:
iommu/amd: Fix undefined behavior in devid_write debugfs function
When for_each_pci_segment() loop completes without finding a matching
segment, the pci_seg pointer is not NULL but points to an invalid memory
location (the list head). Accessing pci_seg->id after the loop causes
undefined behavior.
Fix this by handling the successful case inside the loop and returning
-EINVAL after the loop if no matching segment is found.
References 3
https://git.kernel.org/stable/c/843e149989665f8309ad2efe6048dc76591e1f94
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/8aabe0fba01486b5d893e708b05a8fa7f1b7efbb
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/99d42aef089a07cfb1d404a7227ac9dc7628b497
416baaa9-dc9f-4396-8d5f-8c081fb06d67