lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Tue, 10 Aug 2010 07:01:25 -0500 From: Jason Wessel <jason.wessel@...driver.com> To: "Robert P. J. Day" <rpjday@...shcourse.ca> CC: Jon Masters <jonathan@...masters.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org> Subject: Re: why can't i use gdb to dump module variables anymore? On 08/09/2010 11:06 AM, Robert P. J. Day wrote: > On Sun, 8 Aug 2010, Jon Masters wrote: > > >> On Jul 8, 2010, at 7:51 AM, Robert P. J. Day wrote: >> >>> (gdb) p rpjday_2 >>> Cannot access memory at address 0xffffffffa007c0b4 >>> (gdb) p rpjday_3 >>> Cannot access memory at address 0xffffffffa007c0b8 >>> >> Did you ever get a reply to this one? Were you trying to do this >> locally, by loading a kernel core or using kgdb? >> > > never figured out what was happening here, used to work just fine > for simple gdb debugging of the kernel; nowadays (at least on ubuntu), > not so much. anyway, i'm in bahstahn for linuxcon, staying at the > onyx hotel for first 3 days. my girlfriend is doing a bofs session: > > http://events.linuxfoundation.org/linuxcon2010/mckinnon > > anyway, regarding gdb, this was based on a column i wrote last > year: > > http://www.linux.com/learn/linux-training/33991-the-kernel-newbie-corner-kernel-and-module-debugging-with-gdb > > where it worked just fine -- it's the technique described in LDD3. > but now, on ubuntu 10.04, weirdness. i haven't looked at it closely > again for a while, but if you have any ideas, i'm open to suggestions. > maybe some odd security/selinux/??? setting? > I took a brief look at the instructions you had a the URL. It seemed like something that should probably work ok unless that memory address is really not accessible via /proc/kcore. Depending on the age of the ubuntu system and if you have a serial port or not, kgdb is actually enabled in the kernel and you could certainly try the same test there. It should also be possible to try out a gdb with kernel module awareness on the /proc/kcore. If you want to try and debug it at some point perhaps we'll cross paths at LinuxCON. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists