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.
Thanks,
K.Prasad