Bug 2406753 (CVE-2025-40032)

Summary: CVE-2025-40032 kernel: PCI: endpoint: pci-epf-test: Add NULL check for DMA channels before release
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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OS: Linux   
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Description OSIDB Bzimport 2025-10-28 12:03:38 UTC 
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]
Comment 1 Jon Moroney 2025-10-28 18:38:02 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025102810-CVE-2025-40032-a2fd@gregkh/T