ACPI sleep issues (trap 4)

[coypu%sdf.org@localhost]

hi maxv, port-amd64,

Riccardo has problems with suspend (which has always been problematic
for various driver reasons, too, so the cause may be something else
entirely).

On Tue, Sep 19, 2017 at 01:17:32AM +0200, Riccardo Mottola wrote:
> --- trap (number 4) ---
> acpi_md_sleep_prepare(3,c387f908,3,39,0,bfba1760,c353712c,dc33be80,dc33be90,c03c743a)
> at acpi_md_sleep_prepare+0x37
> acpi_enter_sleep_state(3,dc33bf04,dc33bf00,bfba1764,dc33bf14,3,1000272,42f,74617473,65)
> at acpi_enter_sleep_state+0x15c
> sysctl_hw_acpi_sleepstate(dc33bf14,0,bfba1764,dc33bf00,bfba1760,4,dc33bf04,c46932c0,c35370cc,4)
> at sysctl_hw_acpi_sleepstate+0xba

trap 4 seems to be:
#define	T_PROTFLT	 4	/* protection fault */

it's possible ddb is wrong about the next function because there's
assembly/maybe inlining and it is failing at:
acpi_md_sleep_prepare-> acpi_md_sleep_enter -> acpi_md_sleep_patch

The last function sounds like it may violate W^X unless it's
careful, but I'm not sure what is going on with ACPI and suspend.

What do you think?

Thanks.