fb54ffd600
[ Upstream commit 85afa9ea122dd9d4a2ead104a951d318975dcd25 ] 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 Fixes:8353813c88("PCI: endpoint: Enable DMA tests for endpoints with DMA capabilities") Fixes:5ebf3fc59b("PCI: endpoint: functions/pci-epf-test: Add DMA support to transfer data") Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> [mani: trimmed the stack trace] Signed-off-by: Manivannan Sadhasivam <mani@kernel.org> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Krzysztof Wilczyński <kwilczynski@kernel.org> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20250916025756.34807-1-shinichiro.kawasaki@wdc.com Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>