On Mon, Aug 01, 2016 at 03:51:05PM -0700, Paul Rogers wrote: > > Ken, I thought an invalid instruction of itself was pretty clear. Either > 1) a misconfiguration of the compiler to generate code for a CPU with > more instructions than a Pentium /// has, or > 2) trying to execute arbitrary garbage. >
Yes, but also no: googling suggests a number of specific matches, of which the only one for x86 seemed to be related to x86_64 - but it had some extra words rather than just a plain 'Invalid Instruction'. > > When I'm building a new version I follow the book, using that kernel, > i.e. 3.19. I always keep that around, though later I may patch up. I > did patch this up to 3.19.8, i.e. not beyond the bug-fix territory, > and that's what I was trying to recompile. > I know you think that your firewalling, coupled with the absence of what I regard as modern desktop applications, will keep you safe. But you need to understand that kernels which are not long-term stable (officially, i.e. those initially maintained by Greg K-H at kernel.org - I distrust those maintained by ubuntu which are not official stable kernels) are only maintained for a few weeks. If a vulnerability later becomes known, they will vnot get fixed. If you are running a server, uptime is important. For my server I currently use 4.4 kernels (on 7.9) and I only update those irregularly. Once my old box is in use as a test server I'll be able to test the things I use and therefore I will hope to update my server for every LFS release, still using 4.4 until there is a newer long-term supported stable version. [ snipping, because I can't find the threads I was thinking about ] > > I've never run into configfsf scripts before. I'll have to get back to > you on that. They are specific to gmp, because its devs want to optimize for the build machine. They also get things wrong (e.g. Skylake 'pentium' (the lowest-end of Skylake) doesn't have an instruction they assumed was present - and perhaps some low-end modern CPUs might lie about what they support (I got that from a fedora bug report, no idea if it is true). > > William, not to be argumentative--I'm still feeling my way through this, > trying to understand--but the compiler SAYS it's compiling code for a > PentiumPro and only 387 floating-point. This was the original Chapter 6 > version of gcc which compiled everything else from 6.17 on. When I > recompiled with -march=i686 explicitly yesterday, I got no better > result. I do NOT dismiss doing it once more as you suggest. > > Then it must be in spite of recompiling it explicitly for a base i686 > PPro with CFLAGS=-march=i686. If that's not explicit enough for gmp... > But that give me a search to try. > Again, in gmp rename the configfsf files to the corresponding config file. Please note that recent versions of gcc delegate some processing to gmp. When I talked about building kgcc to compile a kernel, I guess that extra action might be necessary (building pass-1 gcc for a different prefix), but I've only ever built a different gcc for the kernel on the same machine where I use it. P.S. - you are not in my good books, I've just overbaked the loaf I was baking because replying to you and looking for links distracted me for too long (it was in a Dutch Oven in my oven, to preserve moisture, so the smell won't escape until much later). Fortunately, I like well-baked crusty bread, but I was hoping for something softer on this bake so I could decide if the recipe/time/temperature seemed ok (210°C for wholemeal rye still _sounds_ too high to me, I usually use 150°C for much longer). ĸen, hoping it won't break my teeth! -- `I shall take my mountains', said Lu-Tze. `The climate will be good for them.' -- Small Gods -- http://lists.linuxfromscratch.org/listinfo/lfs-support FAQ: http://www.linuxfromscratch.org/blfs/faq.html Unsubscribe: See the above information page Do not top post on this list. A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail? http://en.wikipedia.org/wiki/Posting_style
