From: Laurent Dufour Date: Mon, 24 Feb 2014 16:30:55 +0000 (+0100) Subject: powerpc/crashdump : Fix page frame number check in copy_oldmem_page X-Git-Tag: v3.2.56~47 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=955f8acb2df06b1e28c88dc653293f51b42eb8f0;p=pandora-kernel.git powerpc/crashdump : Fix page frame number check in copy_oldmem_page commit f5295bd8ea8a65dc5eac608b151386314cb978f1 upstream. In copy_oldmem_page, the current check using max_pfn and min_low_pfn to decide if the page is backed or not, is not valid when the memory layout is not continuous. This happens when running as a QEMU/KVM guest, where RTAS is mapped higher in the memory. In that case max_pfn points to the end of RTAS, and a hole between the end of the kdump kernel and RTAS is not backed by PTEs. As a consequence, the kdump kernel is crashing in copy_oldmem_page when accessing in a direct way the pages in that hole. This fix relies on the memblock's service memblock_is_region_memory to check if the read page is part or not of the directly accessible memory. Signed-off-by: Laurent Dufour Tested-by: Mahesh Salgaonkar Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed