Messages in this thread | | | Date | Wed, 5 Oct 2011 11:40:11 -0400 | From | Vivek Goyal <> | Subject | Re: [Patch 1/4][kernel][slimdump] Add new elf-note of type NT_NOCOREDUMP to capture slimdump |
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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
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