Date: Fri, 18 May 2018 18:14:12 -0700 From: Mark Millard <marklmi26-fbsd@yahoo.com> To: Mark Johnston <markj@FreeBSD.org> Cc: freebsd-arch@freebsd.org, FreeBSD PowerPC ML <freebsd-ppc@freebsd.org> Subject: Re: enabling kernel dump options in GENERIC Message-ID: <7F24144E-62CC-480F-A605-D06D2A4C7142@yahoo.com> In-Reply-To: <20180518151120.GE5515@raichu> References: <A133EC52-A05A-49DE-8FCB-63D949CC9A94@yahoo.com> <20180518061739.GC5515@raichu> <F296C61B-467E-48A8-8207-227CE38CF762@yahoo.com> <20180518151120.GE5515@raichu>
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On 2018-May-18, at 8:11 AM, Mark Johnston <markj at reeBSD.org> wrote: > On Fri, May 18, 2018 at 06:14:50AM -0700, Mark Millard wrote: >> On 2018-May-17, at 11:17 PM, Mark Johnston <markj at FreeBSD.org> = wrote: >>=20 >>> On Thu, May 17, 2018 at 08:58:16PM -0700, Mark Millard wrote: >>>> . . . >>>> Bugzilla 214598 (from late 2016) was about >>>> dump for TARGET_ARCH=3Dpowerpc64 builds getting >>>> failures like: >>>>=20 >>>> KDB: enter: manual escape to debugger >>>> [ thread pid 12 tid 10018 ] >>>> Stopped at .kdb_enter+0x70: ori r0, r0, 0x0 >>>> db> dump >>>> Dumping 9 MB (3 chunks) >>>> chunk 0: 10MB (2510 pages) ... ok >>>> chunk 1: 1MB (24 pages) ... ok >>>> chunk 2: 1MB (2 pages)panic: vm_fault: fault on nofault entry, = addr: c000000000022000 >>>>=20 >>>> (A 32-bit powerpc build on the same machine worked >>>> fine for dumping.) >>>>=20 >>>> I just tried it with head -r333594 and I got something >>>> similar. (Old and new mention routines with _bus_dma_map_ >>>> in the names near the trap in the call stack. I've not >>>> done a detailed comparison.) >>>=20 >>> What is the call stack? >>=20 >> I'll have to induce the failure, take a picture of >> the screen that results, and hand type in the >> material for the fairly modern backtrace (-r333594). >> I will not be able to do this until later today. >>=20 >> The bugzilla report has the old backtrace. I did not >> quote all the material from that report in the above. >> So there is something to compare against once I >> supply a modern one. >=20 > My apologies, I missed the fact that the backtrace was included in = that > PR. Since the problem still occurs and apparently manifests with a > similar backtrace, it wouldn't be useful to retest. I'm afraid I don't > have any suggestions on how to make progress here. Given that the new > options give only a small increase in the kernel size, I'm still > inclined to enable them on powerpc64 for consistency with other > architectures. Seems reasonable. May be there are other powerpc64 contexts that can test the updates. Useful or not, I've updated bugzilla 214598 with a backtrace from head -r333594 and have updated its one-line summary to reference -r333594 . Looks like I missed a 0 in: 0xe7ced0: at 0xc00000006ab17fc it should be: 0xe7ced0: at 0xc000000006ab17fc I've no clue why this address has no symbol. I showed more of the stack this time. At least now the old and new can be compared. That is better than forcing folks to rely on my earlier quick look. >> Also: in about a week I'll lose access to the PowerMacs >> for an unknown period of time (weeks? months?). >>=20 =3D=3D=3D Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)
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