Pratysh, > -----Original Message----- > From: Pratyush Anand [mailto:panand at redhat.com] > Sent: Tuesday, May 23, 2017 1:12 PM > To: Hatayama, Daisuke <d.hatayama at jp.fujitsu.com>; > 'ats-kumagai at wm.jp.nec.com' <ats-kumagai at wm.jp.nec.com> > Cc: 'kexec at lists.infradead.org' <kexec at lists.infradead.org>; > 'bhe at redhat.com' <bhe at redhat.com> > Subject: Re: [PATCH 2/2] Revert "[PATCH V2 1/4] x86_64: Calculate page_offset > from pt_load" > > > > On Tuesday 23 May 2017 08:53 AM, Pratyush Anand wrote: > > Hi Hatayama, > > > > On Tuesday 23 May 2017 08:24 AM, Hatayama, Daisuke wrote: > >> This reverts commit 0c9dd01d8ee2e4ec1821a11f5e174fdba56012b8 because > >> the logic works well only on the kdump ELF format. It doesn't work > >> well on sadump vmcores and qemu/KVM guest vmcores created by virsh > >> dump --memory-only command where info->page_offset results in 0. These > >> formats have to depend on kernel version dependency in the current > >> situation. > > > > I do not think that we should just revert it. Revert will break things on > > KASLR enabled kernel. > > > > I have already posted a patch to calculate page_offset when pt_load is not > > available. > > > > http://lists.infradead.org/pipermail/kexec/2017-May/018747.html > > > > Probably,I can improve that patch in next version so that it takes care of > > sadump case as well. > > > > Can you please try following patches from > https://github.com/pratyushanand/makedumpfile.git : devel > > https://github.com/pratyushanand/makedumpfile/commit/ba93c349ac5d097a51c22 > 1e39816da5fef2e5f58 strtoul() is better than strtol() because info->kaslr_offset is of unsigned long, though there's no runtime error in this case. > https://github.com/pratyushanand/makedumpfile/commit/241ecc6d96afbf7be6e02 > f51e882ce5e1e2eb9d0 This patch works fine on sadump vmcores, but doesn't look good on virsh dump --memory-only. The vmcore created by virsh dump --memory-only command is written in ELF format. Virtual addresses assigned into it differs from the kdump one, not reflecting kernel runtime virtual addresses. Here is a sample readelf output: # LANG=C readelf -l /root/vmcore-by-virsh-dump Elf file type is CORE (Core file) Entry point 0x0 There are 7 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align NOTE 0x00000000000001c8 0x0000000000000000 0x0000000000000000 0x0000000000000650 0x0000000000000650 0 LOAD 0x0000000000000818 0x0000000000000000 0x0000000000000000 0x00000000000a0000 0x00000000000a0000 0 LOAD 0x00000000000a0818 0x0000000000000000 0x00000000000a0000 0x0000000000010000 0x0000000000010000 0 LOAD 0x00000000000b0818 0x0000000000000000 0x00000000000c0000 0x0000000000020000 0x0000000000020000 0 LOAD 0x00000000000d0818 0x0000000000000000 0x00000000000e0000 0x0000000000020000 0x0000000000020000 0 LOAD 0x00000000000f0818 0x0000000000000000 0x0000000000100000 0x000000003ff00000 0x000000003ff00000 0 LOAD 0x000000003fff0818 0x0000000000000000 0x00000000f0000000 0x0000000001000000 0x0000000001000000 0 How about using QEMU or VMCOREINFO to distinguish QEMU ELF vmcore from kdump ELF vmcore? I think you know what VMCOREINFO is, and here is QEMU note information example: # LANG=C readelf -n /root/vmcore Displaying notes found at file offset 0x000001c8 with length 0x00000650: Owner Data size Description CORE 0x00000150 NT_PRSTATUS (prstatus structure) CORE 0x00000150 NT_PRSTATUS (prstatus structure) QEMU 0x000001b0 Unknown note type: (0x00000000) QEMU 0x000001b0 Unknown note type: (0x00000000)
