On Wed, 15 Jul 2009, Mulyadi Santosa wrote: > On 7/15/09, Robert P. J. Day <rpjday@xxxxxxxxxxxxxx> wrote: > > > > i'm aware of a number of ways to debug kernel space variables from > > user space, but i'm not sure there's a way to do it if you're > > extremely limited in the information you have at hand. > > > > the scenario: a running 64-bit fedora 11 system. there is no > > "vmlinux" file at hand -- all i have is the vmlinuz file representing > > the running kernel. i have "gdb" installed, and there exist the files > > /proc/kcore and /proc/kallsyms. but given only that, is there any way > > to list the current value of, say, the kernel variable "jiffies"? > > > > i can see in /proc/kallsyms the entry > > > > ffffffffff600880 D __jiffies > > > > but without the vmlinux file, i don't think gdb will do me any good. > > or am i misremembering? > > > > rday > > IIRC, we've talked about it around 2 years ago. In fact, I wrote it > down in my blog. Is this what you're looking for? > > http://the-hydra.blogspot.com/2007/07/observing-kernel-variables-content-with.html > > PS: you might need to adapt how much byte you read since you're using > 64 bit now... i refreshed my memory regarding your blog post and one major change these days is that most distros no longer ship with /dev/kmem. IIRC, using /dev/kmem has been deprecated for a while but, if you really want it, it's still available via "make config." on fedora 11, it's default off. can anyone fill in what the deal is with other distros as they are installed out of the box? and whether there is still any compelling reason to need it for anything? rday -- ======================================================================== Robert P. J. Day Waterloo, Ontario, CANADA Linux Consulting, Training and Annoying Kernel Pedantry. Web page: http://crashcourse.ca Twitter: http://twitter.com/rpjday "Kernel Newbie Corner" column @ linux.com: http://cli.gs/WG6WYX ======================================================================== -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
