On 25.01.2018 16:36, Rolf Eike Beer wrote: > John David Anglin wrote: >> On 2018-01-25 3:59 AM, Rolf Eike Beer wrote: >>> [ 909.756303] Kernel panic - not syncing: Bad Address (null pointer deref?) >>> [ 909.756303] ---[ end Kernel panic - not syncing: Bad Address (null pointer deref?) >>> >>> This is actually the second place where it breaks, before that I had the same >>> with this test (twice): >> Would you post the PIM dump of the most recent HPMC in the service >> menu? > > The service menu does not give any information, as in this older bug: https://bugs.gentoo.org/481768 FWIW, I've tested the testcase from https://bugs.gentoo.org/481768 on a debian system: Linux panama.osuosl.org 4.14.0-2-parisc64-smp #1 SMP Debian 4.14.7-1 (2017-12-28) parisc64 GNU/Linux gdb was version 7.12-6+b1 On debian I can not reproduce the crash. With this sequence: (gdb) break gdb-crash.c:14 (gdb) run (gdb) set tp = {0,0} tp isn't initialized yet before you reach line 25, and as such it points to random memory. I you try to set tp, it depends on what happens (but agreed, it shouldn't crash the kernel). The Debian kernel hasn't any additional hppa-specific patches. >> Also needed >> is the assembler dump of the routine where the HPMC occurred in your >> kernel. You need the >> 64-bit version of objdump for this. I wonder why there isn't any kernel backtrace... Does gentoo uses special compiler-optimization flags? > I have put the kernel on https://opensource.sf-tec.de/c8000-kernel.tar.xz I'd suggest you put some debugging code in your kernel, e.g. in compat_ptrace_request() in kernel/ptrace.c. I think gdb uses PTRACE_POKEDATA to set some userspace memory of a process. It's generic code, so I wonder why it should crash on parisc. You may look at compat_arch_ptrace() in arch/parisc/kernel/ptrace.c too, but it doesn't touch memory as far as I can see... Helge -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
