Re: Problems with 32bit Fedora 7

From: Paul H. Hargrove (PHHargrove_at_lbl_dot_gov)
Date: Wed Aug 29 2007 - 17:51:33 PDT

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    John Hodrien wrote:
    > I can't seem to get blcr working with Fedora 7 32bit.
    > 
    > It seems to build and install happily under x86_64 but on a 32 bit machine
    > I've built the RPM with --target i686 but when loading the kernel modules I
    > get:
    > 
    > vmadump: (from bproc-4.0.0pre8) Erik Hendriks <[email protected]>
    > vmadump: Modified for blcr 0.6.0_b7 <http://ftg.lbl.gov/checkpoint>
    > blcr: Berkeley Lab Checkpoint/Restart (BLCR) module version 0.6.0_b7.
    > blcr: Supports BLCR kernel interface version 0.6.0.
    > blcr: http://ftg.lbl.gov/checkpoint
    > Running kernel does not match the System.map used to build blcr.o
    > 
    > I've tried it with several different kernels (offical F7 releases) with no
    > joy.
    > 
    > Am I missing something obvious?
    > 
    > jh
    
    John,
    
       I don't know exactly what the source of your problem is, but you are 
    not missing anything obvious as far as I can tell.  However, I do have a 
    guess.
    
       To access certain kernel symbols that are not exported to modules, 
    BLCR's configure process locates the symbols in the System.map and 
    encodes the addresses in the BLCR kernel modules.  Such a practice is 
    potentially error prone and could be dangerous if we tried to execute 
    code at arbitrary addresses in the kernel.  For that reason, we extract 
    from System.map some addresses that can be compared against exported 
    symbols and/or entries in the syscall table, and these are checked at 
    module-load time.  The error message you see means that checks comparing 
    addresses in System.map against 2 exported symbols have failed.  This 
    normally means that wrong System.map file was used to build BLCR.
    
       Based on a previously reported issue, I suspect your problem may be 
    related to having a "relocatable" kernel.  If you would, please, provide 
    the output of the following three commands:
    $ grep RELOCATE /boot/config-`uname -r`
    $ grep -e register_chrdev -e register_blkdev /boot/System.map-`uname -r`
    $ grep -e register_chrdev -e register_blkdev /proc/kallsyms
    These are based on file locations on an FC6 system of mine, and might 
    need to be changes slightly for F7.
    
    Based on the output of those commands, I should be able to confirm if 
    the problem is a relocatable kernel, and hopefully formulate a fix.
    
    -Paul
    
    -- 
    Paul H. Hargrove                          PHHargrove_at_lbl_dot_gov
    Future Technologies Group
    HPC Research Department                   Tel: +1-510-495-2352
    Lawrence Berkeley National Laboratory     Fax: +1-510-486-6900
    

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