• Vivek Goyal's avatar
    [PATCH] kdump: Documentation for Kdump · b089f4a6
    Vivek Goyal authored
    This patch contains the documentation for the kexec based crash dump tool.
    
    Quick kdump-howto
    ================================================================
    
    1) Download and build kexec-tools.
    
    2) Download and build the latest kexec/kdump (-mm) kernel patchset.
       Two kernels need to be built in order to get this feature working.
    
      A) First kernel:
       a) Enable "kexec system call" feature:
    	CONFIG_KEXEC=y
       b) Physical load address (use default):
    	CONFIG_PHYSICAL_START=0x100000
       c) Enable "sysfs file system support":
    	CONFIG_SYSFS=y
       d) Boot into first kernel with the command line parameter "crashkernel=Y@X":
          For example: "crashkernel=64M@16M".
    
      B) Second kernel:
       a) Enable "kernel crash dumps" feature:
    	CONFIG_CRASH_DUMP=y
       b) Physical load addreess, use same load address as X in "crashkernel"
          kernel parameter in d) above, e.g., 16 MB or 0x1000000.
    	CONFIG_PHYSICAL_START=0x1000000
       c) Enable "/proc/vmcore support" (Optional, in Pseudo filesystems).
    	CONFIG_PROC_VMCORE=y
    
    3) Boot into the first kernel.
    
    4) Load the second kernel to be booted using:
    
       kexec -p <second-kernel> --crash-dump --args-linux --append="root=<root-dev>
       maxcpus=1 init 1"
    
    5) System reboots into the second kernel when a panic occurs. A module can be
       written to force the panic, for testing purposes.
    
    6) See Documentation/kdump.txt for how to read the first kernel's
       memory image and how to analyze it.
    Signed-off-by: default avatarHariprasad Nellitheertha <hari@in.ibm.com>
    Signed-off-by: default avatarEric Biederman <ebiederm@xmission.com>
    Signed-off-by: default avatarVivek Goyal <vgoyal@in.ibm.com>
    Signed-off-by: default avatarrandy_dunlap <rdunlap@xenotime.net>
    Signed-off-by: default avatarManeesh Soni <maneesh@in.ibm.com>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    b089f4a6
kdump.txt 5.2 KB