In the Linux kernel, the following vulnerability has been resolved: PCI: endpoint: pci-epf-test: Add NULL check for DMA channels before release The fields dmachantx and dmachanrx of the struct pciepftest can be NULL even after EPF initialization. Then it is prudent to check that they have non-NULL values before releasing the channels. Add the checks in pciepftestcleandmachan(). Without the checks, NULL pointer dereferences happen and they can lead to a kernel panic in some cases: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000050 Call trace: dmareleasechannel+0x2c/0x120 (P) pciepftestepcdeinit+0x94/0xc0 [pciepftest] pciepcdeinitnotify+0x74/0xc0 tegrapcieeppexrstirq+0x250/0x5d8 irqthreadfn+0x34/0xb8 irqthread+0x18c/0x2e8 kthread+0x14c/0x210 retfromfork+0x10/0x20 [mani: trimmed the stack trace]