[BUG] GPF on reboot of box

From: Steven Rostedt
Date: Fri Oct 06 2017 - 21:40:04 EST

Starting with v4.14-rc1 my box crashes during a reboot. All I get is
the following:

[ 250.615793] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[ 250.635639] reboot: Restarting system
[ 250.639671] reboot: machine restart
[ 250.643842] general protection fault: 0000 [#1] PREEMPT SMP KASAN

Then nothing. No reboot, it just hangs there.

I bisected it down to this commit:

660da7c9228f ("x86/mm: Enable CR4.PCIDE on supported systems")

If I comment out the setting of X86_CR4_PCIDE in that commit, it boots
fine. But...

I noticed that commit c7ad5ad29 ("x86/mm/64: Initialize CR4.PCIDE
early") moved the problem code from arch/x86/kernel/cpu/common.c to

If I comment it out in v4.14-rc1, it crashes on boot up.

It appears that my box doesn't like having X86_CR4_PCIDE set. it causes
reboot to fail. But it also appears that setting that is required for
some other code to work.


-- Steve