Date: Tue, 27 Aug 2013 07:24:13 -0600 From: Warner Losh <imp@bsdimp.com> To: Andre Oppermann <andre@freebsd.org> Cc: freebsd-arm <freebsd-arm@FreeBSD.org> Subject: Re: ARM network trouble after recent mbuf changes Message-ID: <40769440-B167-4817-9855-1CAB09081AF8@bsdimp.com> In-Reply-To: <521C4CD9.4050308@freebsd.org> References: <1377550636.1111.156.camel@revolution.hippie.lan> <521BC472.7040804@freebsd.org> <521BD531.4090104@sbcglobal.net> <521C4CD9.4050308@freebsd.org>
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On Aug 27, 2013, at 12:53 AM, Andre Oppermann wrote: > On 27.08.2013 00:22, Thomas Skibo wrote: >> On 8/26/13 2:11 PM, Andre Oppermann wrote: >>> >>> Can you try this patch see check if it makes a difference on the bitfield? >> >> Actually, this works for me. But, I'm worried that somewhere else something is going to trip over a >> struct pkthdr not being 64-bit aligned. There are several 64-bit fields in there. > > The problem is the disconnect between the definition of MLEN and MHLEN and > the effective size/padding of struct mbuf. That's the true bug. > > On LP64 all is fine. On i386 it turns out to be fine too because doesn't > care. > > MLEN and MHLEN are incorrectly derived. In fact they should be derived from > stuct mbuf where this padding would be taking into account. However the way > it is structured right now it that would create a circular dependency. > > Please try the patch below to confirm. If it fixes your problem for now > I'm going to commit as an immediate fix while searching for a better long > term stable solution. > > -- > Andre > > Index: sys/mbuf.h > =================================================================== > --- sys/mbuf.h (revision 254953) > +++ sys/mbuf.h (working copy) > @@ -94,6 +94,9 @@ > int32_t mh_len; /* amount of data in this mbuf */ > uint32_t mh_type:8, /* type of data in this mbuf */ > mh_flags:24; /* flags; see below */ > +#if defined(__ILP32__) > + uint32_t mh_pad; /* pad to 64 bit alignment */ > +#endif > }; > > /* There should be a CTASSERT() here to make sure there's no mismatch... Warnerhelp
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