> On Dec 1, 2017, at 9:06 AM, Dave Hansen <dave.han...@linux.intel.com> wrote: > >> On 11/27/2017 02:45 AM, Ingo Molnar wrote: >> --- a/arch/x86/kernel/cpu/common.c >> +++ b/arch/x86/kernel/cpu/common.c >> @@ -1645,11 +1645,13 @@ void cpu_init(void) >> setup_cpu_entry_area(cpu); >> >> /* >> - * Initialize the TSS. Don't bother initializing sp0, as the initial >> - * task never enters user mode. >> + * Initialize the TSS. sp0 points to the entry trampoline stack >> + * regardless of what task is running. >> */ >> set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss); >> load_TR_desc(); >> + load_sp0((unsigned long)&get_cpu_entry_area(cpu)->tss + >> + offsetofend(struct tss_struct, SYSENTER_stack)); >> >> load_mm_ldt(&init_mm); > > Does this also mean that our stack dumps will say "<SYSENTER>" in oopses?
Only if we oops while we're on the trampoline stack. If the oops is due to a bug that isn't in the entry code, then we won't see it. > >> [ 30.811750] CR2: fffffffffdeb2f98 CR3: 0000000423fae001 CR4: >> 00000000001607e0 >> [ 30.819712] Call Trace: >> [ 30.822442] <SYSENTER> >> [ 30.825170] trace_hardirqs_on_thunk+0x1c/0x1c > ... >> [ 31.000571] R13: 0000000000000050 R14: 0000000000000076 R15: >> 00007f59f76f2d60 >> [ 31.008533] </SYSENTER> > > Should we change that string to something more descriptive? I suppose we could rename it to "ENTRY_TRAMPOLINE" or something like that.
