Am Freitag, 26. Januar 2018, 23:31:46 schrieb Helge Deller: > 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. I'm using vanilla, so nothing on my side either. > >> 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... This was with "dmesg -n 8". Without it has shown only the "Bad address" and "end Kernel panic" lines, which is IMHO bad by itself. > Does gentoo uses special compiler-optimization flags? I have none. > > 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... I will not be able to touch any of this until at least mid of next week. If you want to give it a try, check gdb 7.12.1 testsuite. It was one of the first tests that hit this. Eike
Attachment:
signature.asc
Description: This is a digitally signed message part.
