[PATCH 16/18] x86/boot/32: Fix cpu_current_top_of_stack initialization at boot

Andy Lutomirski
2017-10-26T08:28:00Z

cpu_current_top_of_stack's initialization forgot about
TOP_OF_KERNEL_STACK_PADDING. This bug didn't matter because the
idle threads never enter user mode.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/kernel/smpboot.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index ad59edd84de7..06c18fe1c09e 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -961,8 +961,7 @@ void common_cpu_up(unsigned int cpu, struct task_struct *idle)
#ifdef CONFIG_X86_32
/* Stack for startup_32 can be just as for start_secondary onwards */
irq_ctx_init(cpu);
- per_cpu(cpu_current_top_of_stack, cpu) =
- (unsigned long)task_stack_page(idle) + THREAD_SIZE;
+ per_cpu(cpu_current_top_of_stack, cpu) = task_top_of_stack(idle);
#else
initial_gs = per_cpu_offset(cpu);
#endif
--
2.13.6