On Wed, Oct 05, 2011 at 01:11:16PM +0530, K.Prasad wrote: [..] > > Again, note_name and desc_msg seem to be only two exports. Frankly desc > > string seems pretty obivious and we should be able to ignore it. So just > > exporting PANIC_MCE=true or something like that in case of MCE. > > > > Yes, adding a new field to the VMCOREINFO note would have been much > simpler but there's a second part to the kdump + fatal MCE problem which > will need a new elf-note to solve. > > On a system containing 'poisoned' pages (generated as a result of > detecting UC errors which haven't been 'consumed'), if a software bug results > in crashing the machine, the ensuing kdump operation will read from the > faulty memory location. This will trigger a new crash within the context > of the kexec'ed kernel and we want to avoid this. I think in other mail you mentioned that it is not known what happens if we try to read pages marked as "poisoned". > > The plan is to pass-down the list of poisoned memory pages to the second > kernel using an elf-note so that these pages are left untouched during > dump capture. I'm working on an implementation of the same and should > have patches soon. I would say let us first figure out what happens while reading a poisoned page and is this a problem before working on a solution. Thanks Vivek
