• Steven Rostedt (VMware)'s avatar
    ftrace: Have init/main.c call ftrace directly to free init memory · b80f0f6c
    Steven Rostedt (VMware) authored
    Relying on free_reserved_area() to call ftrace to free init memory proved to
    not be sufficient. The issue is that on x86, when debug_pagealloc is
    enabled, the init memory is not freed, but simply set as not present. Since
    ftrace was uninformed of this, starting function tracing still tries to
    update pages that are not present according to the page tables, causing
    ftrace to bug, as well as killing the kernel itself.
    Instead of relying on free_reserved_area(), have init/main.c call ftrace
    directly just before it frees the init memory. Then it needs to use
    __init_begin and __init_end to know where the init memory location is.
    Looking at all archs (and testing what I can), it appears that this should
    work for each of them.
    Reported-by: default avatarkernel test robot <xiaolong.ye@intel.com>
    Reported-by: default avatarFengguang Wu <fengguang.wu@intel.com>
    Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
main.c 25.5 KB