git: 695323ae88c7 - main - acpi_cpu: Fix panic if some CPU devices are disabled.

[Kristof Provost]

On 25 Sep 2021, at 23:01, Alexander Motin wrote:
> The branch main has been updated by mav:
>
> URL: 
> https://cgit.FreeBSD.org/src/commit/?id=695323ae88c71776e131940ed7dedd25365e932f
>
> commit 695323ae88c71776e131940ed7dedd25365e932f
> Author:     Alexander Motin <mav at FreeBSD.org>
> AuthorDate: 2021-09-25 20:54:28 +0000
> Commit:     Alexander Motin <mav at FreeBSD.org>
> CommitDate: 2021-09-25 21:01:28 +0000
>
>     acpi_cpu: Fix panic if some CPU devices are disabled.
>
>     While there, remove couple unneeded global variables.
> ---
>  sys/dev/acpica/acpi_cpu.c | 66 
> +++++++++++++++++++++--------------------------
>  1 file changed, 29 insertions(+), 37 deletions(-)
>
> diff --git a/sys/dev/acpica/acpi_cpu.c b/sys/dev/acpica/acpi_cpu.c
> index ab4ffda7a02e..0577b6eac8b7 100644
> --- a/sys/dev/acpica/acpi_cpu.c
> +++ b/sys/dev/acpica/acpi_cpu.c
> @@ -154,8 +154,6 @@ static struct sysctl_oid *cpu_sysctl_tree;
>  static int		 cpu_cx_generic;
>  static int		 cpu_cx_lowest_lim;
>
> -static device_t		*cpu_devices;
> -static int		 cpu_ndevices;
>  static struct acpi_cpu_softc **cpu_softc;
>  ACPI_SERIAL_DECL(cpu, "ACPI CPU");
>
> @@ -443,26 +441,21 @@ acpi_cpu_attach(device_t dev)
>  static void
>  acpi_cpu_postattach(void *unused __unused)
>  {

I’m seeing this panic on a bhyve VM running an up-to-date main kernel:

	Fatal trap 12: page fault while in kernel mode
	cpuid = 2; apic id = 02
	fault virtual address   = 0x0
	fault code              = supervisor read data, page not present
	instruction pointer     = 0x20:0xffffffff804f643c
	stack pointer           = 0x28:0xffffffff8358bf20
	frame pointer           = 0x28:0xffffffff8358bfa0
	code segment            = base 0x0, limit 0xfffff, type 0x1b
	                        = DPL 0, pres 1, long 1, def32 0, gran 1
	processor eflags        = interrupt enabled, resume, IOPL = 0
	current process         = 0 (swapper)
	trap number             = 12
	panic: page fault
	cpuid = 2
	time = 1
	KDB: stack backtrace:
	db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 
0xffffffff8358bbc0
	vpanic() at vpanic+0x187/frame 0xffffffff8358bc20
	panic() at panic+0x43/frame 0xffffffff8358bc80
	trap_fatal() at trap_fatal+0x387/frame 0xffffffff8358bce0
	trap_pfault() at trap_pfault+0x99/frame 0xffffffff8358bd40
	trap() at trap+0x2a7/frame 0xffffffff8358be50
	calltrap() at calltrap+0x8/frame 0xffffffff8358be50
	--- trap 0xc, rip = 0xffffffff804f643c, rsp = 0xffffffff8358bf20, rbp = 
0xffffffff8358bfa0 ---
	acpi_cpu_postattach() at acpi_cpu_postattach+0x5c/frame 
0xffffffff8358bfa0
	mi_startup() at mi_startup+0x1f0/frame 0xffffffff8358bff0
	btext() at btext+0x22
	KDB: enter: panic
	[ thread pid 0 tid 100000 ]
	Stopped at      kdb_enter+0x37: movq    $0,0x1274f0e(%rip)
	db>

I’ve not done any digging, but given that it seems to die in 
acpi_cpu_postattach() and you touched that last …, well you know how 
that goes.

Best regards,
Kristof