[PATCH]: add dmesg log symbols to /proc/vmcoreinfo lists

Eric W. Biederman ebiederm at xmission.com
Wed Feb 4 10:37:16 EST 2009

Neil Horman <nhorman at tuxdriver.com> writes:

>> That aside we aren't currently exporting log_buf_len, so I don't
>> think this code works actually works.
>> Neil can you add a comment in kernel/printk.c of the algorithm
>> necessary for external tools to decode the ring buffer?
>> We need the comment because people working on kernel/printk.c
>> need to know what is happening and without having to review lots
>> of user space code, and we need the comment to verify that we
>> are exporting the right things.
> Ok, as per Erics comment, I've written this.  It applies on top of whats already
> in your tree Andrew.  It adds some comments on the function in question so that
> anyone working on printk.c will know why we're exporting their symbols.  It also
> modifies slightly the symbols we are exporting so that we can handle dmesg
> buffers that are longer than the standard PAGE_SIZE configuration, and lets us
> detect and handle buffer wraps.

Looks like a good start but what is the algorithm for using the variables?
Given a kernel core file how do you extract the dmesg ring buffer?

It still does not appear obvious to me that you are extracting the
dmesg ring buffer correctly or easily.


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