Hi Dave, If you look into start_kernel() the call to parse_early_param() precedes mm_init(). parse_early_param() eventually calls do_early_param(). do_early_param() parses for "earlycon" in kernel commandline and then calls the setup_function associated with earlycon. I have in my commandline: earlycon=uart8250,mmio32,0x10000000,9600 Call flow starting from drivers/tty/serial/8250_early.c will lead to kmalloc early_param("early_con", setup_early_serial8250_console) setup_early_serial8250_console() early_serial8250_setup() parse_options() ioremap_nocache() ... arch-specific-ioremap -- some form of arch specific __ioremap_caller --- get_vm_area_caller() __get_vm_area_node kzalloc_node kmalloc_node kmalloc Regards, Sukanto On Jan 29, 2012 12:28 PM, "Dave Hylands" <dhylands@gmail.com> wrote:
Hi Sukanto
On Sat, Jan 28, 2012 at 10:02 PM, Sukanto Ghosh <sukanto.cse.iitb@gmail.com> wrote:
I am kind of lost trying to figure out how can kmallocs work if they are called before kmem_cache_init
(e.g. such a case occurs when in start_kernel() we call parse_early_param() (which in turn might call early_serial8250_setup() if earlycon= is used in kernel command-line) before mm_init() (which later calls kmem_cache_init() )
I don't think that you're allowed to call kmalloc during early_setup. I don't see where early_serial8250_setup calls kmalloc.
-- Dave Hylands Shuswap, BC, Canada http://www.davehylands.com