Re: [lfs-support] Kernel bug involving physical to virtual remapping
On Thu, 19 Jul 2018 21:54:20 +0200 Frans de Boer wrote: > I get an syntax error when compiling pager.c. I had this before and > remembered that gcc 8.1 is less forgiving then the 7 series. Frans, FWIW, there was some discussion about gcc 8.1 issues on the kernel mailing list: https://lkml.org/lkml/2018/5/5/181 But, it seems the problems they mention are just warnings, annoying but they don't actually break anything. There are some gcc 8.1 kernel patches here: https://git.kernel.org/pub/scm/linux/kernel/git/jpoimboe/linux.git/log/?h=objtool-gcc8 The one of interest are the top two with "Support GCC 8" in the title. But, I think you'll be more interested in the other set of GCC 8 patches here: https://patchwork.openembedded.org/patch/151479/ two files in the kernel source are changed: tools/lib/str_error_r.c tools/lib/subcmd/pager.c So, there is your pager.c problem. Looking at the patch code, it seems there are/were potential problems in the kernel code which gcc 8.1 detects and warns (or errors) about. But, gcc 8 itself isn't the cause of these issues. > I don't believe that this is the right thread anymore. Yeah, but the recent little odds and ends here sure are interesting. Cheers, Mike -- 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
Re: [lfs-support] Kernel bug involving physical to virtual remapping
On 07/19/2018 09:34 PM, Michael Shell wrote: On Thu, 19 Jul 2018 13:54:19 +0200 Frans de Boer wrote: But I can't compile 4.13. anymore because I now have gcc 8.1 instead of the former 7 series. Frans, What goes wrong when you try to build a 4.13 kernel with gcc 8.1? It should work, right? Are there any good reasons not to use a gcc 8 series kernel? Cheers, Mike I get an syntax error when compiling pager.c. I had this before and remembered that gcc 8.1 is less forgiving then the 7 series. So, I tried to compile the kernel within the LFS development (systemd) environment which ended with said error. The next I tried 4.14.0 and all went well. That said, I just go somewhere else shopping, maybe there is something altered in either systemd (234-8) or the kernel after 4.13.x. I don't believe that this is the right thread anymore. I start with making a VM with a new image of various recent distributions and see if the same problem occurs there. If not, then it must be a LFS problem. -- Frans. -- 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
Re: [lfs-support] Kernel bug involving physical to virtual remapping
On Thu, 19 Jul 2018 13:54:19 +0200 Frans de Boer wrote: > But I can't compile 4.13. anymore because I now have gcc 8.1 instead > of the former 7 series. Frans, What goes wrong when you try to build a 4.13 kernel with gcc 8.1? It should work, right? Are there any good reasons not to use a gcc 8 series kernel? Cheers, Mike -- 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
Re: [lfs-support] Kernel bug involving physical to virtual remapping - CLOSED
On 07/19/2018 08:32 AM, Frans de Boer wrote: I know that Bruce uses bare metal too, but why not using VM's when one can continue developing without having to reboot into an incomplete system environment. Also, if one has multiple systems to spare, bare metal can be a way. If not, VM's are a welcome solution. I generally build on a dedicated development system accessed via ssh. That accomplishes the same level of convenience as a VM, but I prefer validating LFS on a real system. -- Bruce -- 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
Re: [lfs-support] Kernel bug involving physical to virtual remapping - CLOSED
On 19-07-18 14:57, Hazel Russman wrote: On Thu, 19 Jul 2018 13:54:19 +0200 Frans de Boer wrote: However a git bisection showed that this is actually a memory management issue. The kernel commit that caused the problem is : [33c2b803edd13487518a2c7d5002d84d7e9c878f] x86/mm: Remove phys_to_virt() usage in ioremap(). Reintroducing the code: "if (is_ISA_range(phys_addr, last_addr)) return (__force void __iomem *)phys_to_virt(phys_addr);" makes the system bootable again. I have also tested this on a 4.15 kernel and it works there too. Hello Hazel, What you inserted is already available as from the 4.13.0 release. But I can't compile 4.13. anymore because I now have gcc 8.1 instead of the former 7 series. I continue my search and go for 4.14 where the check is removed. But i guess that will fail too and this is no solution to my problem with systemd freezing just after it found out that it is on a VM. --- Frans -- Yes, I can boot 4.13 kernels without any problems. But I wanted an LTS kernel that can keep up with the newest exploits (especially meltdown) and the next LTS after 4.9 is 4.14. I'm using bare iron, not a VM (and no systemd!), but it's rather old hardware. The processor is an Intel Core Duo. I can send you the cpuinfo if you want it. I suspect that if you did build 4.14, it would behave properly; after all, it does for most people. I have 4.15 on my laptop (which has a Via Nano processor) and no problems there. But I'd be happy to carry out any exploratory tests you like on my desktop, since that's the machine that misbehaves. Hello Hazel, I get the impression you have been send to me with the wrong info/background. I have no problem running things on bare metal, but it is the problem with LFS and having systemd on a VM. As explained in the thread 'Booting LFS with Systemd'. I know that Bruce uses bare metal too, but why not using VM's when one can continue developing without having to reboot into an incomplete system environment. Also, if one has multiple systems to spare, bare metal can be a way. If not, VM's are a welcome solution. So, I think that I am chasing the wrong ghost and have a talk with the systemd developers instead. Despite the lack of interest for using VM's, I shall share any positive result with the LFS list. Discussing closed. Regards Frans. -- 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
Re: [lfs-support] Kernel bug involving physical to virtual remapping
On Thu, 19 Jul 2018 13:54:19 +0200 Frans de Boer wrote: > >>> However a git bisection showed that this is actually a memory management > >>> issue. The kernel commit that caused the problem is : > >>> [33c2b803edd13487518a2c7d5002d84d7e9c878f] x86/mm: Remove > >>> phys_to_virt() usage in ioremap(). > >>> > >>> Reintroducing the code: > >>> "if (is_ISA_range(phys_addr, last_addr)) > >>> return (__force void __iomem *)phys_to_virt(phys_addr);" > >>> makes the system bootable again. I have also tested this on a 4.15 kernel > >>> and it works there too. > >>> > > Hello Hazel, > > What you inserted is already available as from the 4.13.0 release. But I > can't compile 4.13. anymore because I now have gcc 8.1 instead of the > former 7 series. > > I continue my search and go for 4.14 where the check is removed. But i > guess that will fail too and this is no solution to my problem with > systemd freezing just after it found out that it is on a VM. > > --- Frans > > -- Yes, I can boot 4.13 kernels without any problems. But I wanted an LTS kernel that can keep up with the newest exploits (especially meltdown) and the next LTS after 4.9 is 4.14. I'm using bare iron, not a VM (and no systemd!), but it's rather old hardware. The processor is an Intel Core Duo. I can send you the cpuinfo if you want it. I suspect that if you did build 4.14, it would behave properly; after all, it does for most people. I have 4.15 on my laptop (which has a Via Nano processor) and no problems there. But I'd be happy to carry out any exploratory tests you like on my desktop, since that's the machine that misbehaves. -- Hazel -- 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
Re: [lfs-support] Kernel bug involving physical to virtual remapping
On 07/17/2018 03:15 PM, Hazel Russman wrote: On Tue, 17 Jul 2018 14:06:09 +0200 Frans de Boer wrote: On 07/14/2018 06:56 PM, Hazel Russman wrote: Gentlemen, I was given your contact details by Michael Shell, who has been helping me to troubleshoot this problem via the Linux From Scratch support list. For some time now I have been unable to boot recent kernels (4.14 or later) on my rather elderly desktop machine. The kernel panics during boot and the problem seems (superficially) to lie in the acpi driver. At least that is where the visible error messages come from. Booting with "acpi=off" works but is hardly an ideal solution. However a git bisection showed that this is actually a memory management issue. The kernel commit that caused the problem is : [33c2b803edd13487518a2c7d5002d84d7e9c878f] x86/mm: Remove phys_to_virt() usage in ioremap(). Reintroducing the code: "if (is_ISA_range(phys_addr, last_addr)) return (__force void __iomem *)phys_to_virt(phys_addr);" makes the system bootable again. I have also tested this on a 4.15 kernel and it works there too. If you want me to carry out any further tests, I would be happy to oblige, but do please bear in mind that I am not an expert, so you will need to give fairly basic instructions. Hazel Russman Hazel, sorry but where should I remove phys_to_virt()? If I delete the complete if statement in the iounmap function, and replace that with the above code, i get compile errors. btw: acpi=off does not solve the issue too. Frans. -- No, it's the other way around. phys_to_virt() doesn't get removed; it gets inserted/reinserted just above the warning not to let normal RAM be remapped. This is code that was in the kernel before but someone took it out and that was what was causing me all that trouble. Here's the patch that I made: --- linux-4.13.0-rc1/arch/x86/mm/ioremap.c 2018-07-14 13:27:21.0 +0100 +++ linux-4.13.0-rc1.new/arch/x86/mm/ioremap.c 2018-07-14 16:00:14.071456762 +0100 @@ -103,7 +103,12 @@ (unsigned long long)phys_addr); WARN_ON_ONCE(1); return NULL; - } + } +/* Don't remap the low PCI/ISA area, it's always mapped.. +*/ + if (is_ISA_range(phys_addr, last_addr)) + return (__force void __iomem *)phys_to_virt(phys_addr); + /* * Don't allow anybody to remap normal RAM that we're using.. Sorry if this is a bit inexpert. I'm not used to creating patches and I did the actual edit by hand. I didn't touch anything else in that file. And it built normally with just that edit. Hello Hazel, What you inserted is already available as from the 4.13.0 release. But I can't compile 4.13. anymore because I now have gcc 8.1 instead of the former 7 series. I continue my search and go for 4.14 where the check is removed. But i guess that will fail too and this is no solution to my problem with systemd freezing just after it found out that it is on a VM. --- Frans -- 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
Re: [lfs-support] Kernel bug involving physical to virtual remapping
On Tue, 17 Jul 2018 14:06:09 +0200 Frans de Boer wrote: > On 07/14/2018 06:56 PM, Hazel Russman wrote: > > Gentlemen, > > > > I was given your contact details by Michael Shell, who has been helping me > > to troubleshoot this problem via the Linux From Scratch support list. > > > > For some time now I have been unable to boot recent kernels (4.14 or later) > > on my rather elderly desktop machine. The kernel panics during boot and the > > problem seems (superficially) to lie in the acpi driver. At least that is > > where the visible error messages come from. Booting with "acpi=off" works > > but is hardly an ideal solution. > > > > However a git bisection showed that this is actually a memory management > > issue. The kernel commit that caused the problem is : > > [33c2b803edd13487518a2c7d5002d84d7e9c878f] x86/mm: Remove > > phys_to_virt() usage in ioremap(). > > > > Reintroducing the code: > > "if (is_ISA_range(phys_addr, last_addr)) > > return (__force void __iomem *)phys_to_virt(phys_addr);" > > makes the system bootable again. I have also tested this on a 4.15 kernel > > and it works there too. > > > > If you want me to carry out any further tests, I would be happy to oblige, > > but do please bear in mind that I am not an expert, so you will need to > > give fairly basic instructions. > > > > Hazel Russman > > > > > Hazel, sorry but where should I remove phys_to_virt()? If I delete the > complete if statement in the iounmap function, and replace that with the > above code, i get compile errors. > > btw: acpi=off does not solve the issue too. > > Frans. > > -- No, it's the other way around. phys_to_virt() doesn't get removed; it gets inserted/reinserted just above the warning not to let normal RAM be remapped. This is code that was in the kernel before but someone took it out and that was what was causing me all that trouble. Here's the patch that I made: --- linux-4.13.0-rc1/arch/x86/mm/ioremap.c 2018-07-14 13:27:21.0 +0100 +++ linux-4.13.0-rc1.new/arch/x86/mm/ioremap.c 2018-07-14 16:00:14.071456762 +0100 @@ -103,7 +103,12 @@ (unsigned long long)phys_addr); WARN_ON_ONCE(1); return NULL; - } + } +/* Don't remap the low PCI/ISA area, it's always mapped.. +*/ + if (is_ISA_range(phys_addr, last_addr)) + return (__force void __iomem *)phys_to_virt(phys_addr); + /* * Don't allow anybody to remap normal RAM that we're using.. Sorry if this is a bit inexpert. I'm not used to creating patches and I did the actual edit by hand. I didn't touch anything else in that file. And it built normally with just that edit. -- -- 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
Re: [lfs-support] Kernel bug involving physical to virtual remapping
On Tue, 17 Jul 2018 14:06:09 +0200 Frans de Boer wrote: > Hazel, sorry but where should I remove phys_to_virt()? If I delete the > complete if statement in the iounmap function, and replace that with the > above code, i get compile errors. Frans, You put (do not remove anything) the statement: if (is_ISA_range(phys_addr, last_addr)) return (__force void __iomem *)phys_to_virt(phys_addr); around line 106 of arch/x86/mm/ioremap.c just before the lines: /* * Don't allow anybody to remap normal RAM that we're using.. */ pfn = phys_addr >> PAGE_SHIFT; You can how the older code was altered here: https://patchwork.kernel.org/patch/9847859/ Mike -- 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
Re: [lfs-support] Kernel bug involving physical to virtual remapping
On 07/14/2018 06:56 PM, Hazel Russman wrote: Gentlemen, I was given your contact details by Michael Shell, who has been helping me to troubleshoot this problem via the Linux From Scratch support list. For some time now I have been unable to boot recent kernels (4.14 or later) on my rather elderly desktop machine. The kernel panics during boot and the problem seems (superficially) to lie in the acpi driver. At least that is where the visible error messages come from. Booting with "acpi=off" works but is hardly an ideal solution. However a git bisection showed that this is actually a memory management issue. The kernel commit that caused the problem is : [33c2b803edd13487518a2c7d5002d84d7e9c878f] x86/mm: Remove phys_to_virt() usage in ioremap(). Reintroducing the code: "if (is_ISA_range(phys_addr, last_addr)) return (__force void __iomem *)phys_to_virt(phys_addr);" makes the system bootable again. I have also tested this on a 4.15 kernel and it works there too. If you want me to carry out any further tests, I would be happy to oblige, but do please bear in mind that I am not an expert, so you will need to give fairly basic instructions. Hazel Russman Hazel, sorry but where should I remove phys_to_virt()? If I delete the complete if statement in the iounmap function, and replace that with the above code, i get compile errors. btw: acpi=off does not solve the issue too. Frans. -- 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
Re: [lfs-support] Kernel bug involving physical to virtual remapping
On 07/14/2018 06:56 PM, Hazel Russman wrote: Gentlemen, I was given your contact details by Michael Shell, who has been helping me to troubleshoot this problem via the Linux From Scratch support list. For some time now I have been unable to boot recent kernels (4.14 or later) on my rather elderly desktop machine. The kernel panics during boot and the problem seems (superficially) to lie in the acpi driver. At least that is where the visible error messages come from. Booting with "acpi=off" works but is hardly an ideal solution. However a git bisection showed that this is actually a memory management issue. The kernel commit that caused the problem is : [33c2b803edd13487518a2c7d5002d84d7e9c878f] x86/mm: Remove phys_to_virt() usage in ioremap(). Reintroducing the code: "if (is_ISA_range(phys_addr, last_addr)) return (__force void __iomem *)phys_to_virt(phys_addr);" makes the system bootable again. I have also tested this on a 4.15 kernel and it works there too. If you want me to carry out any further tests, I would be happy to oblige, but do please bear in mind that I am not an expert, so you will need to give fairly basic instructions. Hazel Russman Thnx Hazel, I will try this in the comming days ahead. --- Frans. -- 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
[lfs-support] Kernel bug involving physical to virtual remapping
Gentlemen, I was given your contact details by Michael Shell, who has been helping me to troubleshoot this problem via the Linux From Scratch support list. For some time now I have been unable to boot recent kernels (4.14 or later) on my rather elderly desktop machine. The kernel panics during boot and the problem seems (superficially) to lie in the acpi driver. At least that is where the visible error messages come from. Booting with "acpi=off" works but is hardly an ideal solution. However a git bisection showed that this is actually a memory management issue. The kernel commit that caused the problem is : [33c2b803edd13487518a2c7d5002d84d7e9c878f] x86/mm: Remove phys_to_virt() usage in ioremap(). Reintroducing the code: "if (is_ISA_range(phys_addr, last_addr)) return (__force void __iomem *)phys_to_virt(phys_addr);" makes the system bootable again. I have also tested this on a 4.15 kernel and it works there too. If you want me to carry out any further tests, I would be happy to oblige, but do please bear in mind that I am not an expert, so you will need to give fairly basic instructions. Hazel Russman -- -- 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
