Date: Wed, 1 Mar 2017 00:26:20 +0100 From: Michael Gmelin <freebsd@grem.de> To: Eric van Gyzen <vangyzen@FreeBSD.org> Cc: cem@freebsd.org, "freebsd-current@freebsd.org" <freebsd-current@freebsd.org> Subject: Re: panic: invalid bcd xxx Message-ID: <20170301002620.6a5e35ce@bsd64.grem.de> In-Reply-To: <b753effa-aa7f-ff20-d127-28e1e827f304@FreeBSD.org> References: <20170228224739.167f2273@bsd64.grem.de> <226a00fa-5d04-0aa7-e0cc-6078edde6639@FreeBSD.org> <CAG6CVpXGQds1NYOOd1trYBTE8KNm=VYA3mq9yK3gjjVMt3NNpA@mail.gmail.com> <b753effa-aa7f-ff20-d127-28e1e827f304@FreeBSD.org>
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On Tue, 28 Feb 2017 17:16:02 -0600 Eric van Gyzen <vangyzen@FreeBSD.org> wrote: > On 02/28/2017 16:57, Conrad Meyer wrote: > > On Tue, Feb 28, 2017 at 2:31 PM, Eric van Gyzen > > <vangyzen@freebsd.org> wrote: > >> Your system's real-time clock is returning garbage. r312702 added > >> some input validation a few weeks ago. Previously, the kernel was > >> reading beyond the end of an array and either complaining about > >> the clock or setting it to the wrong time based on whatever was in > >> the memory beyond the array. > >> > >> The added validation shouldn't be an assertion because it operates > >> on data beyond the kernel's control. Try this: > >> > >> --- sys/libkern.h (revision 314424) > >> +++ sys/libkern.h (working copy) > >> @@ -57,8 +57,10 @@ > >> bcd2bin(int bcd) > >> { > >> > >> - KASSERT(bcd >= 0 && bcd < LIBKERN_LEN_BCD2BIN, > >> - ("invalid bcd %d", bcd)); > >> + if (bcd < 0 || bcd >= LIBKERN_LEN_BCD2BIN) { > >> + printf("invalid bcd %d\n", bcd); > >> + return (0); > >> + } > >> return (bcd2bin_data[bcd]); > >> } > > > > I don't think removing this assertion and truncating to zero is the > > right thing to do. Adding an error return to this routine is a > > little much, though. I think probably the caller should perform > > input validation between the broken device and this routine. > > Either of those would be a much better solution. This was just a > quick hack to get the memstick to boot. > Thanks for your response. I'm not in a hurry, so I can wait for a proper solution. Let me know if I should test anything or can help in some other way. -m -- Michael Gmelin
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