On Thu, Jan 19, 2017 at 10:00 AM, Arvind Yadav <arvind.yadav.cs@xxxxxxxxx> wrote: > Here, If ioremap_nocache will fail. It will return NULL. > Kernel can run into a NULL-pointer dereference. > This error check will avoid NULL pointer dereference. > uart.port.mapbase = address; > uart.port.membase = ioremap_nocache(address, 16); > + if (!uart.port.membase) { > + dev_warn(&dev->dev, "Failed to map memory\n"); > + return -ENOMEM; > + } You also may do something like void __iomem *base; ... base = ioremap_nocache(...); if (!base) return -ENOMEM; // I doubt the message is useful, up to you memset(&uart, 0, sizeof(uart)); ... uart.port.membase = base; -- With Best Regards, Andy Shevchenko -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html