In the Linux kernel, the following vulnerability has been resolved:
powerpc/xive: fix kmemleak caused by incorrect chip_data lookup
The kmemleak reports the following memory leak:
Unreferenced object 0xc0000002a7fbc640 (size 64): comm "kworker/8:1", pid 540, jiffies 4294937872 hex dump (first 32 bytes): 01 00 00 00 00 00 00 00 00 00 09 04 00 04 00 00 ................ 00 00 a7 81 00 00 0a c0 00 00 08 04 00 04 00 00 ................ backtrace (crc 177d48f6): __kmalloc_cache_noprof+0x520/0x730 xive_irq_alloc_data.constprop.0+0x40/0xe0 xive_irq_domain_alloc+0xd0/0x1b0 irq_domain_alloc_irqs_parent+0x44/0x6c pseries_irq_domain_alloc+0x1cc/0x354 irq_domain_alloc_irqs_parent+0x44/0x6c msi_domain_alloc+0xb0/0x220 irq_domain_alloc_irqs_locked+0x138/0x4d0 __irq_domain_alloc_irqs+0x8c/0xfc __msi_domain_alloc_irqs+0x214/0x4d8 msi_domain_alloc_irqs_all_locked+0x70/0xf8 pci_msi_setup_msi_irqs+0x60/0x78 __pci_enable_msix_range+0x54c/0x98c pci_alloc_irq_vectors_affinity+0x16c/0x1d4 nvme_pci_enable+0xac/0x9c0 [nvme] nvme_probe+0x340/0x764 [nvme]
This occurs when allocating MSI-X vectors for an NVMe device. During allocation the XIVE code creates a struct xive_irq_data and stores it in irq_data->chip_data.
When the MSI-X irqdomain is later freed, xive_irq_free_data() is responsible for retrieving this structure and freeing it. However, after commit cc0cc23babc9 ("powerpc/xive: Untangle xive from child interrupt controller drivers"), xive_irq_free_data() retrieves the chip_data using irq_get_chip_data(), which looks up the data through the child domain.
This is incorrect because the XIVE-specific irq data is associated with the XIVE (parent) domain. As a result the lookup fails and the allocated struct xive_irq_data is never freed, leading to the kmemleak report shown above.
Fix this by retrieving the irq_data from the correct domain using irq_domain_get_irq_data() and then accessing the chip_data via irq_data_get_irq_chip_data().