| Message ID | 20230614153226.117768-1-cymi20@fudan.edu.cn |
|---|---|
| State | New |
| Headers | show |
| Series | serial: 8250_lpss: Fix missing check for return value of pci_get_slot() | expand |
On Wed, Jun 14, 2023 at 08:32:26AM -0700, Chenyuan Mi wrote: > The pci_get_slot() function may return NULL, which may > cause null pointer deference, and most other callsites of > pci_get_slot() do Null check. Add Null check for return > value of pci_get_slot(). > > Found by our static analysis tool. ... > dma_dev = pci_get_slot(pdev->bus, PCI_DEVFN(PCI_SLOT(pdev->devfn), 0)); > + if (!dma_dev) > + return -ENODEV; This adds (almost) a dead code. The function 0 must be present in accordance with the PCI specification (even earliest version of it state that). If pci_get_slot() returns a NULL, in this case it means that something, much bigger issue, happens and this check won't help us to do anything anyway.
On Wed, Jun 14, 2023 at 08:32:26AM -0700, Chenyuan Mi wrote: > The pci_get_slot() function may return NULL, which may > cause null pointer deference, and most other callsites of > pci_get_slot() do Null check. Add Null check for return > value of pci_get_slot(). > > Found by our static analysis tool. Please read Documentation/process/researcher-guidelines.rst for how to do this properly. Until then, we obviously can not take these types of patches. greg k-h
diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c index 0e43bdfb7459..05af5865ee1b 100644 --- a/drivers/tty/serial/8250/8250_lpss.c +++ b/drivers/tty/serial/8250/8250_lpss.c @@ -137,6 +137,8 @@ static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port) } dma_dev = pci_get_slot(pdev->bus, PCI_DEVFN(PCI_SLOT(pdev->devfn), 0)); + if (!dma_dev) + return -ENODEV; param->dma_dev = &dma_dev->dev; param->m_master = 0;
The pci_get_slot() function may return NULL, which may cause null pointer deference, and most other callsites of pci_get_slot() do Null check. Add Null check for return value of pci_get_slot(). Found by our static analysis tool. Signed-off-by: Chenyuan Mi <cymi20@fudan.edu.cn> --- drivers/tty/serial/8250/8250_lpss.c | 2 ++ 1 file changed, 2 insertions(+)