Currently, the secondary vCPUs in Hyper-V VTL context lack support for parallel startup. Therefore, relying on the single initial_stack fetched from the current task structure suffices for all vCPUs. However, common initial_stack risks stack corruption when parallel startup is enabled. In order to facilitate parallel startup, use the initial_stack from the per CPU idle thread instead of the current task. Fixes: 18415f33e2ac ("cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE") Signed-off-by: Saurabh Sengar <ssengar@xxxxxxxxxxxxxxxxxxx> --- arch/x86/hyperv/hv_vtl.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c index 96e6c51515f5..a54b46b673de 100644 --- a/arch/x86/hyperv/hv_vtl.c +++ b/arch/x86/hyperv/hv_vtl.c @@ -12,6 +12,7 @@ #include <asm/i8259.h> #include <asm/mshyperv.h> #include <asm/realmode.h> +#include <../kernel/smpboot.h> extern struct boot_params boot_params; static struct real_mode_header hv_vtl_real_mode_header; @@ -71,7 +72,8 @@ static int hv_vtl_bringup_vcpu(u32 target_vp_index, u64 eip_ignored) struct ldttss_desc *ldt; struct desc_struct *gdt; - u64 rsp = current->thread.sp; + struct task_struct *idle = idle_thread_get(target_vp_index); + u64 rsp = (unsigned long)idle->thread.sp; u64 rip = (u64)&hv_vtl_ap_entry; native_store_gdt(&gdt_ptr); -- 2.34.1