On Wed, 2011-07-13 at 18:46 +0200, Martin Schwidefsky wrote: > On Wed, 13 Jul 2011 12:02:39 -0400 > Vivek Goyal <vgoyal at redhat.com> wrote: > > So in case of stand alone dump, you save the calculated checksum of > > kdump kernel at disk and not in memory? And then calculate the checksum > > of memory image of kdump kernel and decide whether kdump kenrel is > > corrupted or not? > > > > If yes, this sounds more reliable as checksum of kernel is stored on > > some disk/tape. > > No, the checksum for the purgatory code is stored in memory. If the purgatory > code is corrupted you would have to corrupt the checksum in a very specific > way as well to make it fail. Currently we store the checksums for the loaded *kexec segments* in memory at the end of kexec_load(). The stand-alone dump tools also calculate the checksums for all segments and compare them with the stored checksums. The dump tools can do that because we have meminfos for all segments. A meminfo element contains: * address of memory chunk * size of memory chunk * checksum of memory chunk (calculated at the end of kexec_load() Michael
