Date: Sat, 4 Aug 2018 09:58:43 -0500 From: Kyle Evans <kevans@freebsd.org> To: Ian Lepore <ian@freebsd.org> Cc: Konstantin Belousov <kostikbel@gmail.com>, freebsd-current Current <freebsd-current@freebsd.org>, Eitan Adler <eadler@freebsd.org> Subject: Re: panic: mutex pmap not owned at ... efirt_machdep.c:255 Message-ID: <CACNAnaF9vqxrKsOUDTjMhHOyTX==0irDbrHrmLbHUZ_kqH1MSg@mail.gmail.com> In-Reply-To: <1533394281.9860.5.camel@freebsd.org> References: <CAF6rxg=4OnHEJa1OnJerMeEKD66nZg3j-H-XZ-9YAA1TE_NoDQ@mail.gmail.com> <CACNAnaFv9Gj%2BM2Gb8FbwY5q56dnTR6OgjZ5qth9gjr8LreHeow@mail.gmail.com> <20180804083720.GJ6049@kib.kiev.ua> <CACNAnaGZJxm=_oM_f0xinUe2NZ=tZn3w%2BnLTE62_r9EAm0UuTA@mail.gmail.com> <20180804131352.GL6049@kib.kiev.ua> <CACNAnaFUto6gSaDx3vrgnSykRfBhV_Mgx4OLaXJgENvgqjgSHg@mail.gmail.com> <1533394281.9860.5.camel@freebsd.org>
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On Sat, Aug 4, 2018 at 9:51 AM, Ian Lepore <ian@freebsd.org> wrote: > On Sat, 2018-08-04 at 08:56 -0500, Kyle Evans wrote: >> On Sat, Aug 4, 2018 at 8:13 AM, Konstantin Belousov <kostikbel@gmail. >> com> wrote: >> > >> > On Sat, Aug 04, 2018 at 08:05:24AM -0500, Kyle Evans wrote: >> > > >> > > On Sat, Aug 4, 2018 at 3:37 AM, Konstantin Belousov <kostikbel@gm >> > > ail.com> wrote: >> > > > >> > > > On Fri, Aug 03, 2018 at 11:27:02PM -0500, Kyle Evans wrote: >> > > > > >> > > > > >> > > > > This seems odd- pmap lock is acquired at [1], then asserted >> > > > > shortly >> > > > > later at [2]... I avoid some of this stuff as well as I can, >> > > > > but is it >> > > > > actually possible for PCPU_GET(...) acquired curpmap to not >> > > > > match >> > > > > curthread->td_proc->p_vmspace->vm_pmap in this context? >> > > > > >> > > > > [1] https://svnweb.freebsd.org/base/head/sys/dev/efidev/efirt >> > > > > .c?view=markup#l260 >> > > > > [2] https://svnweb.freebsd.org/base/head/sys/amd64/amd64/efir >> > > > > t_machdep.c?view=markup#l254 >> > > > There could be that curpcpu not yet synced with proc0 pmap. It >> > > > could be >> > > > fixed. >> > > > >> > > > But it is not clear to me why efi_arch_enter() is called >> > > > there. I see >> > > > the check for GetTime belonging to the range described by a map >> > > > descriptor. >> > > > I do not see why do you need an enter into the EFI context for >> > > > comparing >> > > > integers. >> > > This probably could have been documented better, but efi_runtime >> > > pointer may (always?) point into runtime service memory that >> > > isn't >> > > valid/available at that point, so we get a fault and panic when >> > > dereferencing it to grab rt_gettime address. We ran into this >> > > wall >> > > when adding the check originally. >> > Wouldn't it be enough to access it by translating physical address >> > into >> > DMAP ? >> Ah, sure, sure. [1] is proper form, yeah? >> >> [1] https://people.freebsd.org/~kevans/efi-dmap.diff > > What do we do on 32-bit arm that has no dmap but may have efi runtime > support? > This should probably just be compiled out for !arm64 && !x86 - its sole purpose was to compensate for outdated loader.efi that hasn't done the SetVirtualAddressMap. EFI on 32-bit ARM is "new" enough that it shouldn't have this problem.
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