panic: mutex pmap not owned at ... efirt_machdep.c:255

[Doug Ambrisko]

On Tue, Aug 07, 2018 at 08:29:49PM +0300, Konstantin Belousov wrote:
| On Tue, Aug 07, 2018 at 11:50:44AM -0500, Kyle Evans wrote:
| > On Tue, Aug 7, 2018 at 12:09 AM, Eitan Adler <eadler at freebsd.org> wrote:
| > > On Mon, 6 Aug 2018 at 11:27, Kyle Evans <kevans at freebsd.org> wrote:
| > >>
| > >> On Sun, Aug 5, 2018 at 5:43 AM, Konstantin Belousov <kostikbel at gmail.com> wrote:
| > >> > On Sat, Aug 04, 2018 at 09:46:39PM -0500, Kyle Evans wrote:
| > >> >>
| > >> >> He now gets a little further, but ends up with the same panic due to
| > >> >> efirtc_probe trying to get time to verify the rtc's actually
| > >> >> implemented. What kind of approach must we take to ensure curcpu is
| > >> >> synced?
| > >> >
| > >> > It does not panic for me, when I load efirt.ko from the loader prompt.
| > >> > Anyway, try this
| > >>
| > >> Right, I also don't get a panic on any of my machines from this.
| > >> Hopefully he'll have a chance to try this soon.
| > >
| > > This change has no impact: it still panics in the same way as without the patch.
| > >
| > 
| > That seems indicative of a bigger problem, since we use proc0
| > throughout all these bits so we should still be dealing with the same
| > pmap that got passed to pmap_pinit0 when we grab
| > curthread->td_proc->p_vmspace->vm_pmap.
| 
| Can you confirm that you get the early efi_enter() call from rtc code,
| when you preload the module or compile it into the kernel ?

When I ran into this, I did this change:

Index: dev/efidev/efirt.c
===================================================================
--- dev/efidev/efirt.c	(revision 337264)
+++ dev/efidev/efirt.c	(working copy)
@@ -257,7 +257,8 @@
 	if (efi_runtime == NULL)
 		return (ENXIO);
 	td = curthread;
-	curpmap = &td->td_proc->p_vmspace->vm_pmap;
+//	curpmap = &td->td_proc->p_vmspace->vm_pmap;
+	curpmap = PCPU_GET(curpmap);
 	PMAP_LOCK(curpmap);
 	mtx_lock(&efi_lock);
 	fpu_kern_enter(td, NULL, FPU_KERN_NOCTX);
@@ -272,7 +273,8 @@
 
 	efi_arch_leave();
 
-	curpmap = &curproc->p_vmspace->vm_pmap;
+//	curpmap = &curproc->p_vmspace->vm_pmap;
+	curpmap = PCPU_GET(curpmap);
 	td = curthread;
 	fpu_kern_leave(td, NULL);
 	mtx_unlock(&efi_lock);

Don't know if it is right.  Some previous code used both
	curpmap = PCPU_GET(curpmap);
and
	curpmap = &td->td_proc->p_vmspace->vm_pmap;
recently it was changes to only use
	curpmap = &td->td_proc->p_vmspace->vm_pmap;

Things seem to work after that.  I was able to repro. it with 
qemu-system-x86_64 in UEFI mode.  I think it also failed in
bhyve UEFI mode.

Thanks,

Doug A.