From Bugzilla Helper: User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.12) Gecko/20050915 Description of problem: Kernel hangs when booting on a system with more than 8 logical processors. When booting RHEL 3.0 on an x86_64 system with more than 8 logical processors, the kernel will hang. This occurs for both the boot kernel and the default kernel. This problem was observed on a S3E3143 model Intel Software Development Platform, which has four dual core Intel Xeon (Paxville MP) processors. When running with hyperthreading turned off, this system has only eight logical processors, and the kernel boots and runs fine. When running with hyperthreading turned on, this system has sixteen logical processors, and the hang on boot is observed. The following is output of an attempted PXE-based kickstart with hyperthreading turned on: ---begin--- Broadcom UNDI PXE-2.1 v7.7.5 Copyright (C) 2000-2004 Broadcom Corporation Copyright (C) 1997-2000 Intel Corporation All rights reserved. booting x86_64 kernel... CLIENT MAC ADDR: 00 0E 0C 42 93 50 GUID: A8271196 F8FC 11D9 B138 000BAB01F3DF CLIENT IP: 10.17.255.45 MASK: 255.255.255.0 DHCP IP: 10.17.255.28 GATEWAY IP: 10.17.255.254 PXELINUX 2.08 2003-12-12 Copyright (C) 1994-2003 H. Peter Anvin UNDI data segment at: 00093990 UNDI data segment size: 4EF0 UNDI code segment at: 00098880 UNDI code segment size: 6A48 PXE entry point found (we hope) at 9888:00DA My IP address seems to be 0A11FF2D 10.17.255.45 ip=10.17.255.45:10.17.192.11:10.17.255.254:255.255.255.0 TFTP prefix: Trying to load: pxelinux.cfg/01-00-0e-0c-42-93-50 Trying to load: pxelinux.cfg/0A11FF2D Loading rhel-3.0-u5-64/vmlinuz.......................... Loading rhel-3.0-u5-64/initrd.img...................................................... Ready. . Decompressing Linux...done. Booting the kernel. ----end---- The system hangs at this point. This exact same kickstart runs completely normally when hyperthreading is disabled, and the system runs fine after it is loaded. If hyperthreading is subsequently turned back on, the hang occurs again, as follows: ---begin--- Booting 'Red Hat Enterprise Linux AS (2.4.21-37.EL)' booting x86_64 kernel... root (hd0,0) Filesystem type is ext2fs, partition type 0x83 kernel /vmlinuz-2.4.21-37.EL ro root=LABEL=/ [Linux-bzImage, setup=0x1400, size=0x162755] initrd /initrd-2.4.21-37.EL.img [Linux-initrd@ 0x37f34000, 0xbb538 bytes] . Decompressing Linux...done. Booting the kernel. ----end---- The system hangs at this point. Note that the first transcript is for an attempt with Update 5. The second is for Update 6. Both hang in the same manner and at the same point. Note too that the 32-bit (x86) kernels work fine. Version-Release number of selected component (if applicable): How reproducible: Always Steps to Reproduce: 1. Attempt to boot RHEL 3.0 x86_64 on a system with more than eight logical processors. Actual Results: The system hangs. Expected Results: The system should boot. Additional info: Please note that I have opened a separate feature request bug (Bug 174759) requesting support for more than eight logical processors in x86_64. If that work is completed, it should also resolve this bug. If that work is not completed, however, the problem of hang on boot should still be addressed.
Could you try this again as follows: set up for serial console capture, then boot with the option "earlyprintk=ttyS0,115200" (or use your favorite baud rate). This should hopefully produce more output between the "Booting" message and the hang.
Unfortunately, I can't... The only system we had which had more than eight logical processors (and the system on which this problem was observed) was a S3E3143 model Intel Software Development Platform on loan from Intel. This box has since been returned to Intel. I'll check with my Intel rep and see if they can follow up on this, though...
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