On Thu, Mar 01, 2012 at 09:04:32AM -0800, Eugene Surovegin wrote: > On Thu, Mar 1, 2012 at 7:09 AM, Vivek Goyal <vgoyal at redhat.com> 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. > >> > > > > Hi Eugene, > > > > Where do we make assumption that crash_notes address is page aligned? > > I never said that. I said that assumption was that note chunks were > physically contiguous. > > [snip] > > > Are you referring to the fact that note could be stored on two different > > physical pages and then kexec-tools does not know about the physical > > address of second page, hence second kernel does not know about it > > and we never read that data. That sounds like a problem. > > Yes. This is exactly what happens in some cases. Ok. Thanks for clarifying. Patch looks good to me. Acked-by: Vivek Goyal <vgoyal at redhat.com> Vivek
