https://bugzilla.kernel.org/show_bug.cgi?id=206669
--- Comment #5 from npig...@gmail.com --- bugzilla-dae...@bugzilla.kernel.org's on February 26, 2020 8:28 pm: > https://bugzilla.kernel.org/show_bug.cgi?id=206669 > > --- Comment #4 from John Paul Adrian Glaubitz (glaub...@physik.fu-berlin.de) > --- > (In reply to npiggin from comment #3) >> Do you have tracing / ftrace enabled in the host kernel for any >> reason? Turning that off might let the oops message get printed. > > Seems that this is the case in the Debian kernel, yes: > > root@watson:~# grep -i ftrace /boot/config-5.4.0-0.bpo.3-powerpc64le > CONFIG_KPROBES_ON_FTRACE=y > CONFIG_HAVE_KPROBES_ON_FTRACE=y > CONFIG_HAVE_DYNAMIC_FTRACE=y > CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS=y > CONFIG_HAVE_FTRACE_MCOUNT_RECORD=y > CONFIG_FTRACE=y > CONFIG_FTRACE_SYSCALLS=y > CONFIG_DYNAMIC_FTRACE=y > CONFIG_DYNAMIC_FTRACE_WITH_REGS=y > CONFIG_FTRACE_MCOUNT_RECORD=y > # CONFIG_FTRACE_STARTUP_TEST is not set > root@watson:~# > > Do you have the kernel command option at hand which disables ftrace on the > command line? Is it just ftrace=off? Hmm, not sure, Documentation/admin-guide/kernel-parameters.txt seems to say that wouldn't work. I thought it might only be going down that path if you have already done some tracing. Perhaps ensure /sys/kernel/debug/tracing/tracing_on is set to 0, and then `echo 1 > /sys/kernel/debug/tracing/free_buffer` before you start the test. >> > FWIW, the kernel image comes from this Debian package: >> > >> >> >> >> >> >> >> >> http://snapshot.debian.org/archive/debian/20200211T210433Z/pool/main/l/linux/linux-image-5.4.0-0.bpo.3-powerpc64le_5.4.13-1%7Ebpo10%2B1_ppc64el.deb >> >> Okay. Any chance you could test an upstream kernel? > > Sure, absolutely. Any preference on the version number? Current head if you're feeling lucky, but v5.5 if not. But you can give the ftrace test a try with the debian kernel first if you've got it ready to go. >> Don't bother testing that after the above -- panic_on_oops happens >> after oops_begin(), so it won't help unfortunately. > > Okay. > >> Attmepting to get into xmon might though, if you boot with xmon=on. >> Try that if tracing wasn't enabled, or disabling it doesn't help. > > Okay. I will try to disable ftrace first, then retrigger the crash. Cool Thanks, Nick -- You are receiving this mail because: You are watching the assignee of the bug.