CVE-2025-40032

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 dma_chan_tx and dma_chan_rx of the struct pci_epf_test 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 pci_epf_test_clean_dma_chan().

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:
dma_release_channel+0x2c/0x120 (P)
pci_epf_test_epc_deinit+0x94/0xc0 [pci_epf_test]
pci_epc_deinit_notify+0x74/0xc0
tegra_pcie_ep_pex_rst_irq+0x250/0x5d8
irq_thread_fn+0x34/0xb8
irq_thread+0x18c/0x2e8
kthread+0x14c/0x210
ret_from_fork+0x10/0x20

[mani: trimmed the stack trace]

More information : https://git.kernel.org/stable/c/0c5ce6b6ccc22d486cc7239ed908cb0ae5363a7b