[PATCH] kdump: force page alignment for per-CPU crash notes.

[Eugene Surovegin]

On Wed, Feb 29, 2012 at 5:18 PM, Simon Horman <horms at verge.net.au> wrote:

> On Wed, Feb 29, 2012 at 09:21:23AM -0800, Eugene Surovegin wrote:
> > Per-CPU allocations are not guaranteed to be physically contiguous.
> > However, kdump kernel and user-space code assumes that per-CPU
> > memory, used for saving CPU registers on crash, is.
> > This can cause corrupted /proc/vmcore in some cases - the main
> > symptom being huge ELF note section.
> >
> > Force page alignment for note_buf_t to ensure that this assumption holds.
>
> Ouch. I'm surprised there is an allocation on crash, perhaps
> it could at least be done earlier? And am I right in thinking
> that this change increases the likely hood that the allocation
> could fail?
>

I'm not following. This allocation is done on start-up, not on crash.
If you cannot allocate this much memory on system boot, I'm not sure what
else you can do on this system....

-- 
Eugene
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