On Thu, Jun 04, 2020 at 10:03:59AM -0400, Brian Gerst wrote:
> The idle tasks created for each secondary CPU already have a random stack
> canary generated by fork().  Copy the canary to the percpu variable before
> starting the secondary CPU which removes the need to call
> boot_init_stack_canary().
> 
> Signed-off-by: Brian Gerst <brgerst@gmail.com>
> ---
>  arch/x86/include/asm/stackprotector.h | 12 ++++++++++++
>  arch/x86/kernel/smpboot.c             | 12 +-----------
>  arch/x86/xen/smp_pv.c                 |  2 --
>  3 files changed, 13 insertions(+), 13 deletions(-)

arch/x86/kernel/smpboot.c: In function ‘common_cpu_up’:
arch/x86/kernel/smpboot.c:1003:2: error: implicit declaration of function ‘cpu_init_stack_canary’; did you mean ‘boot_init_stack_canary’? [-Werror=implicit-function-declaration]
  cpu_init_stack_canary(cpu, idle);
make[2]: *** [scripts/Makefile.build:281: arch/x86/kernel/smpboot.o] Error 1
make[1]: *** [scripts/Makefile.build:497: arch/x86/kernel] Error 2
make: *** [Makefile:1764: arch/x86] Error 2

.config attached.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette