Re: [Crash-utility] [patch] crash: Show warning message if specified dumpfile has its kernel data scrubbed out.

The new version of makedumpfile 1.4.0 allows user to filter out kernel data (e.g. security keys, confidential/secret information etc.) from the vmcore. The data to be filtered out is poisoned with character 'X' (0x58 in Hex). The filtered ELF kdump now carries a new ELF note section "ERASEINFO" that contains eraseinfo data. The filtered compressed kdump now contains new members (offset_eraseinfo, size_eraseinfo) int the sub header with new header version 5. With the above change in place, there may be instances where the filtered dumpfile may not be readable OR may not be helpful in analyzing the problem using crash tool. Most of the time crash tool will be able to read/analyze the dump unless someone scrubs out the data on which crash utility is dependent on. Hence, This patch adds support into crash utility to detect the above changes and show early warning message to the user about the fact that he is dealing with filtered dumpfile. This patch adds support for "help -n" output to display the filter data strings that are appended to the dumpfile or stored in an ELF note. Signed-off-by: Mahesh Salgaonkar <mahesh(a)linux.vnet.ibm.com&gt;