On Sat, Oct 7, 2017 at 6:36 AM, Steven Rostedt <rost...@goodmis.org> wrote: > > [ Replying from an actual computer this time ] > > On Fri, 6 Oct 2017 19:21:26 -0700 > Nadav Amit <nadav.a...@gmail.com> wrote: > >> IIRC, there was a problem in rc1, which should be resolved in newer rcs. >> If you need to run rc1, you can try to use the kernel parameter “nopcid". > > I noticed the bug when I rebased my work on top of rc3 and started > testing that. I only mentioned rc1 because that's the first tagged > release that had the bug in it. If it is fixed in a later release, then > great! But I don't see that as the case (I haven't tested work on top > of rc3). > > I'd like to have this fixed without having to do workarounds like > adding nopcid to the kernel command line. If it is a bug for me, I'm > sure it's going to be a bug for many others that wont know how to > complain about it. >
Howdy, batman! Can you try the attached patch?
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index 54180fa6f66f..add33f600531 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -105,6 +105,10 @@ void __noreturn machine_real_restart(unsigned int type) load_cr3(initial_page_table); #else write_cr3(real_mode_header->trampoline_pgd); + + /* Exiting long mode will fail if CR4.PCIDE is set. */ + if (static_cpu_has(X86_FEATURE_PCID)) + cr4_clear_bits(X86_CR4_PCIDE); #endif /* Jump to the identity-mapped low memory code */
