Date: Sat, 04 Aug 2018 08:51:21 -0600 From: Ian Lepore <ian@freebsd.org> To: Kyle Evans <kevans@freebsd.org>, Konstantin Belousov <kostikbel@gmail.com> Cc: 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: <1533394281.9860.5.camel@freebsd.org> In-Reply-To: <CACNAnaFUto6gSaDx3vrgnSykRfBhV_Mgx4OLaXJgENvgqjgSHg@mail.gmail.com> 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>
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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? -- Ian
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