Re: [Crash-utility] [Patch 1/4][kernel][slimdump] Add new elf-note of type NT_NOCOREDUMP to capture slimdump

On Tue, Oct 04, 2011 at 10:04:37AM -0400, Vivek Goyal wrote: > On Mon, Oct 03, 2011 at 01:02:03PM +0530, K.Prasad wrote: > > There are certain types of crashes induced by faulty hardware in which > > capturing crashing kernel's memory (through kdump) makes no sense (or sometimes > > dangerous). > > > > A case in point, is unrecoverable memory errors (resulting in fatal machine > > check exceptions) in which reading from the faulty memory location from the > > kexec'ed kernel will cause double fault and system reset (leaving no > > information for the user). > > Prasad, > > I am just trying to remember what was wrong with Andi's approach of > disable MCE while copying the dump? > Hi Vivek, The behaviour upon a read operation on an UC memory location is undefined and so we want to avoid it (previously discussed here: http://article.gmane.org/gmane.linux.kernel/1146799).

When we disable MCE and copy the dump, we will invariably read the faulty memory location.