Description of problem: Attempting to boot any smp kernel hangs with <pre> CPU1: Intel(R) Core(TM)2 CPU 6300 @ 1.86GHz stepping 06 Total of 2 processors activated (7461.49 BogoMIPS). ENABLING IO-APIC IRQs ..TIMER: vector=031 pin1=2 pin2=-1 checking TSC synchronization across 2 CPUs: passed. Brought up 2 CPUs zapping low mappings. checking if image is initramfs... it is Freeing initrd memory: 379k freed NET: Registered protocol family 16 PCI: Using MMCONFIG mtrr: v2.0 (20020519) ACPI: Subsystem revision 20040816 ACPI: Interpreter enabled ACPI: USING IOAPIC for interrupt routing ACPI: PCI Root Bridge [PCI0] (00:00) PCI: Probing PCI hardware (bus 00) </pre> I tried 2.6.9-22.ELsmp, 2.6.9-34.ELsmp and 2.6.9-42.0.2.ELsmp. With acpi=off to the kernel, 2.6.9-22 and 2.6.9-34 (smp and up) can boot, but then they only see one CPU. 2.6.9-42.0.2 can't boot at all, not even with acpi=off. Adding noapic makes no difference. I also tried the corresponding up kernels, as well as the i686 versions of 2.6.9-34 and 2.6.9-42.0.2, both up and smp. They all behave the exact same way. The machine is brand new and consists of motherboard, CPU, RAM, one ATA HDD, one ATA DVD-RW, and no other devices in it. memtest86 says the RAM is good. Although a hardware fault is rather unlikely, I don't have a second identical system so I cannot positively rule out the possibility. Additionally, I am using CentOS and don't have access to real RHEL, so I can't rule out the hypothetical chance that the error was introduced downstream. Obviously, the machine is not in production. If you would like to use it for testing, it's all yours. If you'd be willing to lend me a few RHEL kernels to test, I'm game too. How reproducible: Every time.
I compiled 2.6.9-34.0.1.ELsmp locally with -march=nocona -mcpu=nocona. It behaved as the 2.6.9-34.ELsmp, i.e. it hang without acpi=off and could boot with acpi=off but would then only see one CPU. I saved the .config that was left in BUILD after rpmbuilding 2.6.9-34.0.1.ELsmp (the last version built was largesmp) and used it unchanged to compile a vanilla 2.6.17.11. Now, that works just fine without any boot arguments and it recognises and uses both CPUs. I guess that this rules out faulty hardware and it also rules out a bad kernel config in the rpm packages. What's left to blame for the distribution kernel problems is either a bad patch or a bug that has been fixed in the latest vanilla. My offer to you to use my machine for testing stands, but in that case don't waste time because now that I got it working it will soon go in production.
Zenon if 2.6.17 worked for your system then you should use the latest FC6 kernel which is based on 2.6.18. Systems are certified by vendors against specific RHEL releases, systems without that certification may or may not boot properly. I pinged the Intel developer to see if he had any input for you. Glad to hear that vanilla 2.6.17 worked for you with Centos, you should consider using Fedora. I am closing out this request as resolved in currentrelease, as it seems that RHEL5 will work properly based on your input.
Ehum, FC6 does not exist yet, but there's a kernel nicknamed "fc6" at ftp://download.fedora.redhat.com/pub/fedora/linux/core/development/x86_64/os/Fedora/RPMS/kernel-2.6.18-1.2708.fc6.x86_64.rpm . It won't install on RHEL4 (clone) due to a pile of unsatisfied dependencies. I installed it anyway with --nodeps and it booted OK and could see both cores. If RHEL5 is based on this, the problem will be gone in RHEL5. However, RHEL4 has many years of life ahead and many Intel 946GZIS boards will be sold in those years, also to people who can't upgrade to RHEL5. Therefore, IMO, this bug should stay open for RHEL4 until either a kernel upgrade or a backport fix it for this distro too. As for considering Fedora, I think that for most people who use RHEL, cloned or not, Fedora is not an option. Its fast release cycles, short life span and bleeding-edge tech simply don't match a conservative and prudent admin's requirements in a high-demand environment. I think you should consider this when you decide whether or not to fix the RHEL4 kernel for the 946GZIS.