Hi Fredrik, > This was an interesting exercise. I suspect GDB runs out of memory since > > # gdb -q -c /proc/kcore > [New process 1] > Segmentation fault > > with > > # dmesg | tail -n3 > do_page_fault(): sending SIGSEGV to gdb for invalid read access from 000000a8 > epc = 00953910 in gdb[400000+6d1000] > ra = 009538b8 in gdb[400000+6d1000] > > to me looks like GDB does a NULL pointer deference (the PS2 has 32 MiB of > RAM, of which 16 MiB is used for a ramdisk in my setup). GDB once could > handle core files remotely, but this capability is apparently now lost: > > https://www.redhat.com/archives/crash-utility/2011-December/msg00019.html If you can't access /proc/kcore with GDB locally, for whatever reason, then `dd' it (or a part of it); to a regular file and copy it to another machine. Use cross-GDB if necessary. With 16 MiB of RAM available only it can be getting really tight; the kernel itself takes half of it too I suppose. > In this case I'm wondering whether kcore contains proper ELF headers. What > is the output of readelf for your kcore? I have this: Looks reasonable to me. > Returning to the more awkward /dev/mem device, the "bad address" error with > for example > > # xxd -s $(( 0x80000000 )) -l 256 /dev/mem > xxd: /dev/mem: Bad address You need to use bus (physical) rather than virtual addresses with /dev/mem, so: # xxd -s 0 -l 256 /dev/mem or suchlike. HTH, Maciej
