Date: Wed, 8 Aug 2018 01:42:07 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Doug Ambrisko <ambrisko@ambrisko.com> Cc: Kyle Evans <kevans@freebsd.org>, Eitan Adler <eadler@freebsd.org>, freebsd-current Current <freebsd-current@freebsd.org> Subject: Re: panic: mutex pmap not owned at ... efirt_machdep.c:255 Message-ID: <20180807224207.GF1884@kib.kiev.ua> In-Reply-To: <20180807214910.GA53911@ambrisko.com> References: <CAF6rxg=4OnHEJa1OnJerMeEKD66nZg3j-H-XZ-9YAA1TE_NoDQ@mail.gmail.com> <CACNAnaFv9Gj%2BM2Gb8FbwY5q56dnTR6OgjZ5qth9gjr8LreHeow@mail.gmail.com> <20180804083720.GJ6049@kib.kiev.ua> <CACNAnaF1anCXzjivX0jqur%2Bomy_%2B6Xv4D%2BDttzLQY9g6qaxYbw@mail.gmail.com> <20180805104341.GX6049@kib.kiev.ua> <CACNAnaHAoVE57aw7UUPO=psOXz0nnUaCSXtJSFhpBo%2BBhp_qnw@mail.gmail.com> <CAF6rxgmGLbLnMacc_Bb7_RKEAb6vazBjXwcECzsuVqJWKMrBvQ@mail.gmail.com> <CACNAnaHdgbe%2BVDZC-gV-oU7=DgNZhEfg1Uanrs0Lh4MgkLXsOQ@mail.gmail.com> <20180807172949.GD1884@kib.kiev.ua> <20180807214910.GA53911@ambrisko.com>
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On Tue, Aug 07, 2018 at 02:49:10PM -0700, Doug Ambrisko wrote:
> 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@freebsd.org> wrote:
> | > > On Mon, 6 Aug 2018 at 11:27, Kyle Evans <kevans@freebsd.org> wrote:
> | > >>
> | > >> On Sun, Aug 5, 2018 at 5:43 AM, Konstantin Belousov <kostikbel@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.
The pcpu curpmap and curproc vmspace pmap should be synced. Esp. since
there is code relying on this early. I do not want to paper it over.
In fact, try this please. Ignore my previous change.
diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 572b2197453..4bce36cc0e5 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -7536,7 +7536,8 @@ pmap_activate_sw(struct thread *td)
PCPU_SET(kcr3, pmap->pm_cr3);
PCPU_SET(ucr3, pmap->pm_ucr3);
}
- }
+ } else
+ PCPU_SET(curpmap, pmap);
if (pmap->pm_ucr3 != PMAP_NO_CR3) {
rsp0 = ((vm_offset_t)PCPU_PTR(pti_stack) +
PC_PTI_STACK_SZ * sizeof(uint64_t)) & ~0xful;
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