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

[Andrew Turner]

> On 27 Sep 2021, at 09:16, Kristof Provost <kp at freebsd.org> wrote:
> 
> 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 <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.
> 
I hit what looks to be the same issue on arm64. In my case it was a NULL pointer dereference on cpu_softc because acpi_cpu_probe never called malloc as I’m booting using FDT.

I’ve pushed a fix for this in 4e50efb1.

Andrew