printk problems...

Riley Williams (rhw@bigfoot.com)
Thu, 12 Nov 1998 18:58:18 +0000 (GMT)


Hi All.

>> It is known that some routers are not RFC 1122 compliant, and send
>> out bogus error respones to invalid broadcasts.

>> Later Linux kernels detect this, printing a kernel message.

>> This is great as a diagnostic tool, but extremely annoying when
>> your console gets about 10 of these every minute. ;)

>> Presently, there is no kernel option to turn off these options.
>> This patch gives that option - It is made against 2.1.127.

> Can you make this a sysctl instead ? It really ought to be a run
> time configurable. Another possible help is to also remember the
> last couple of addresses warned about, since most people seem to
> only have one broken router per network ;)

Perhaps an even simpler option would be to have these messages sent as
KERN_DEBUG ones, as those are by default ignored, but can be enabled
by adding or tweaking an entry in /etc/syslog.conf - I now have all
KERN_DEBUG level messages sent to /var/log/kernel.debug so I can check
what's going on...

Incidentally, I have a couple of questions re printk which have been
occasioned by my reading the kernel sources recently...

1. Should printk be used for partial lines, or only for complete
lines? At the moment, it's used for both, but my understanding
was that it timestamps each time it's called, in which case it
will mangle partial lines.

2. Should all printk() lines use one of the KERN_xxx message level
options? Many don't, especially in modules coded by one Linus
Torvalds (at least, out of those I've looked at).

3. If the answer to (2) is YES, would it be worth my while to go
through the kernel source and add the tags to those printk()'s
without them, where I can determine an appropriate level, then
submit a patch making the relevant changes?

4. If I did, who would I submit the patch to? It would almost
certainly cut right across all maintainance boundaries...

Advice much appreciated...

Best wishes from Riley.

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