[+Ard] Hi Julien, Thank you for reporting this issue. On Thu, May 12, 2016 at 07:24:08PM +0100, Julien Grall wrote: > Hello Geoff, > > On 14/04/16 22:21, Geoff Levand wrote: > >This series adds the core support for kexec re-boot and kdump on ARM64. This > >version of the series combines Takahiro's kdump patches with my kexec patches. > >Please consider all patches for inclusion. > > > >To load a second stage kernel and execute a kexec re-boot or to work with kdump > >on ARM64 systems a series of patches to kexec-tools [2], which have not yet been > >merged upstream, are needed. Please update to the latest if you have been using > >an older version. > > > >To examine vmcore (/proc/vmcore), you should use > > - gdb v7.7 or later > > - crash v7.1.1 or later > > I have been trying to use crash dump with your branch without much > success on juno-r2: > > WARNING: could not find MAGIC_START! > crash: cannot determine base kernel version > crash: /root/vmlinux and /root/coredump.kernel do not match! > > Looking at the debug log (-p 5), the translation va -> pa computed > by crash is wrong. > > The physical address expected is 0x80a76b28, but crash return 0x88a76b28. Yeah, this is due to Ard's KASLR patches (especially, f9040773b7bb: "arm64: move kernel image to base of vmalloc area"). Now that the kernel image (and so all the kernel symbols) is located in the vmalloc area, which is below PAGE_OFFSET, we can't use liner mapping conversion for va -> pa in order to access kernel data in the core image. I'm sure that the image (/proc/vmcore) is still sane, and we will have to fix a user-space tool, i.e. crash. The good news is that I've already confirmed that we could read the core image successfully by adding a bit nasty hack to the tool. I'll let you know once a refined patch gets ready. Thanks for your patience, -Takahiro AKASHI > I am using crash built from [1] and the panic has been created using > /proc/sysrq-trigger. > > Also, crash dump seems to always report that Xen is running even > when KVM was in used (see logs [2]) below. > > Lastly, crash fails with an error after a couple of minutes (see logs [2]). > > How you seen such errors during your testing? > > Regards, > > [1] https://github.com/crash-utility/crash > [2] http://pastebin.com/wC8w44SN > > -- > Julien Grall
