Date: Tue, 17 Feb 2009 22:21:52 -0700 (MST) From: "M. Warner Losh" <imp@bsdimp.com> To: tinderbox@FreeBSD.org Cc: mips@FreeBSD.org, current@FreeBSD.org Subject: Re: [head tinderbox] failure on mips/mips Message-ID: <20090217.222152.-109416210.imp@bsdimp.com> In-Reply-To: <20090217.203647.-1518647466.imp@bsdimp.com> References: <20090218023328.227617302F@freebsd-current.sentex.ca> <20090217.203647.-1518647466.imp@bsdimp.com>
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In message: <20090217.203647.-1518647466.imp@bsdimp.com> "M. Warner Losh" <imp@bsdimp.com> writes: : In message: <20090218023328.227617302F@freebsd-current.sentex.ca> : FreeBSD Tinderbox <tinderbox@freebsd.org> writes: : : /src/usr.sbin/bsnmpd/modules/snmp_mibII/../../../../contrib/bsnmp/snmp_mibII/mibII.c:1016: warning: cast increases required alignment of target type : : there's still 3 or 4 of these in the tree that I'm trying to track : back to root cause. A simple (void *) fixes the problem, but I want : to understand the issues before I slap that bad-boy in there... The first one is: case RTM_IFINFO: ifm = (struct if_msghdr *)rtm; mib_extract_addrs(ifm->ifm_addrs, (u_char *)(ifm + 1), addrs); if ((ifp = mib_find_if_sys(ifm->ifm_index)) == NULL) break; rtm is of type struct rt_msghdr. This has an alignment requirement of 4 on mips, at least on 32-bit mips (the biggest data element is a u_long). struct if_msghdr has an alignment requirement of 8, because time_t is int64_t on MIPS, which is 8-bytes in size. One way to fix this is to add __aligned(8) to struct rt_msghdr to compensate for this. Otherwise, if the time_t element is referenced in ifm_data we'll core dump. But that doesn't seem very portable and seems like a hack. Adding (void *) to "fix" the warning would be even worse... Anybody else have any ideas? Warner
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