On Sun, Aug 25, 2019 at 11:38:50AM -0700, Linus Torvalds wrote: > On Sun, Aug 25, 2019 at 11:29 AM Borislav Petkov <b...@suse.de> wrote: > > > > My lazy, sticky Sunday brain could come up only with this: > > Looks reasonable, except I think this only runs at boot, right? > > I _think_ the boot CPU is magical during suspend/resume, and doesn't > do the full CPU bringup. > > Although I guess this would still report it for the other CPU's? I > didn't check if this gets done during CPU bringup of secondary CPU's.
So after adding a dump_stack() at the beginning of this function (yap, I'm lazy) I see during boot: [ 0.230044] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc5+ #9 [ 0.230759] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.1-1 04/01/2014 [ 0.231690] Call Trace: [ 0.232097] dump_stack+0x46/0x60 [ 0.232496] x86_init_rdrand+0xf/0xa1 [ 0.232496] identify_cpu+0x352/0x540 [ 0.232496] identify_boot_cpu+0xc/0x8f [ 0.232496] check_bugs+0x28/0x8e4 [ 0.232496] ? __get_locked_pte+0x13e/0x1f0 [ 0.232496] start_kernel+0x4ae/0x4ca and also on all the remaining 15 CPUs of the guest. Then, suspending to RAM and resuming right afterwards says: [ 51.620230] Disabling non-boot CPUs ... [ 51.622745] smpboot: CPU 1 is now offline [ 51.627264] smpboot: CPU 2 is now offline [ 51.630581] smpboot: CPU 3 is now offline [ 51.634533] smpboot: CPU 4 is now offline [ 51.638715] smpboot: CPU 5 is now offline [ 51.642590] smpboot: CPU 6 is now offline [ 51.645890] smpboot: CPU 7 is now offline [ 51.649076] smpboot: CPU 8 is now offline [ 51.652362] smpboot: CPU 9 is now offline [ 51.655647] smpboot: CPU 10 is now offline [ 51.659061] smpboot: CPU 11 is now offline [ 51.662772] smpboot: CPU 12 is now offline [ 51.665863] smpboot: CPU 13 is now offline [ 51.667980] smpboot: CPU 14 is now offline [ 51.671644] smpboot: CPU 15 is now offline [ 51.675640] ACPI: Low-level resume complete [ 51.675640] PM: Restoring platform NVS memory [ 51.675640] Enabling non-boot CPUs ... [ 51.728674] x86: Booting SMP configuration: [ 51.729015] smpboot: Booting Node 0 Processor 1 APIC 0x1 [ 51.625362] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.3.0-rc5+ #9 [ 51.625362] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.1-1 04/01/2014 [ 51.625362] Call Trace: [ 51.625362] dump_stack+0x46/0x60 [ 51.625362] x86_init_rdrand+0xf/0xa1 [ 51.625362] identify_cpu+0x352/0x540 [ 51.625362] identify_secondary_cpu+0x13/0x80 [ 51.625362] smp_store_cpu_info+0x45/0x50 [ 51.625362] start_secondary+0x4f/0x180 [ 51.625362] secondary_startup_64+0xa4/0xb0 [ 51.740833] CPU1 is up ... and the remaining 14(!). Yes, this doesn't run on the BSP during resume. I think the better thing to do would be to stick this in a CPUHP notifier... Btw: Subject: Undelivered Mail Returned to Sender ... <pu...@hygon.cn>: Host or domain name not found. Name service error for name=spam01.hygon.cn type=AAAA: Host found but no data record of requested type hygon.cn domain doesn't even resolve from here. Oh boy. -- Regards/Gruss, Boris. SUSE Software Solutions Germany GmbH, GF: Felix Imendörffer, HRB 247165, AG München