6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Shin'ichiro Kawasaki shinichiro.kawasaki@wdc.com
[ 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: 8353813c88ef ("PCI: endpoint: Enable DMA tests for endpoints with DMA capabilities") Fixes: 5ebf3fc59bd2 ("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 --- drivers/pci/endpoint/functions/pci-epf-test.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-)
--- a/drivers/pci/endpoint/functions/pci-epf-test.c +++ b/drivers/pci/endpoint/functions/pci-epf-test.c @@ -282,15 +282,20 @@ static void pci_epf_test_clean_dma_chan( if (!epf_test->dma_supported) return;
- dma_release_channel(epf_test->dma_chan_tx); - if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) { + if (epf_test->dma_chan_tx) { + dma_release_channel(epf_test->dma_chan_tx); + if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) { + epf_test->dma_chan_tx = NULL; + epf_test->dma_chan_rx = NULL; + return; + } epf_test->dma_chan_tx = NULL; - epf_test->dma_chan_rx = NULL; - return; }
- dma_release_channel(epf_test->dma_chan_rx); - epf_test->dma_chan_rx = NULL; + if (epf_test->dma_chan_rx) { + dma_release_channel(epf_test->dma_chan_rx); + epf_test->dma_chan_rx = NULL; + } }
static void pci_epf_test_print_rate(struct pci_epf_test *epf_test,