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

misc: pci_endpoint_test: Fix array underflow in pci_endpoint_test_ioctl()

Commit eefb83790a0d ("misc: pci_endpoint_test: Add doorbell test case")
added NO_BAR (-1) to the pci_barno enum which, in practical terms,
changes the enum from an unsigned int to a signed int.  If the user
passes a negative number in pci_endpoint_test_ioctl() then it results in
an array underflow in pci_endpoint_test_bar().