On Fri, Jan 29, 2021 at 11:28 PM Jürgen Groß <[email protected]> wrote: > > On 29.01.21 21:12, Roman Shaposhnik wrote: > > Hi! > > > > I'm trying to see how much mileage I can get out of > > crash(1) 7.2.8 (based on gdb 7.6) when it comes to > > analyzing crash dumps taken via xl dump-core (this > > is all on x86_64 with stock Xen v. 4.14). > > > > The good news is that the image actually does load > > up but it throws the following WARNINGs in the process: > > > > WARNING: cannot access vmalloc'd module memory > > crash: read error: kernel virtual address: ffffffff93613480 type: > > "fill_task_struct" > > WARNING: active task ffffffff93613480 on cpu 0 not found in PID hash > > crash: read error: kernel virtual address: ffffffff93613480 type: > > "fill_task_struct" > > WARNING: cannot read log_buf contents > > > > And then the info that it gives me around basic things like > > ps, mod, log, etc. is really super limited (and I am now suspecting > > may even be wrong). > > > > Since I was primarily after dmesg/log initially, I tried: > > crash> log > > log: WARNING: cannot read log_buf contents > > > > Then I tried taking an xl dump-core from the domU that was still > > very much alive and happy and got similar results -- so it clearly > > doesn't seem to be related to the state domU is in. > > > > As matter of fact, I actually got to the desired dmesg output > > by simply running strings(1) on the core file -- so the info is > > definitely there -- but I guess some kind of index/reference maybe > > broken. > > > > With all that in mind, if there's anyone on this ML who has recently > > done Xen DomU crash dump analysis -- I would definitely appreciate > > the pointers! > > For me it just works (openSUSE).
Can you please run: crash --version and readelf -a XXXX (on the xl dump-core output) and post the results? also, what version of Xen are you using? > I tried a pv guest only with a 4.4 kernel, though. I would really appreciate it if you could try it on HVM so that I know whether it is an issue that only affects my setup or other folks (especially after seeing answers to above). Thanks, Roman.
