lkml.org 
[lkml]   [2004]   [Dec]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Announce: kdb v4.4 is available for kernel 2.6.10
Keith Owens wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> KDB (Linux Kernel Debugger) has been updated.

Hi,

I browsed the patch quickly to check for kallsyms uses, and validate
them, and it generally seems correct.

There is however one comment that makes me wonder:
*2.6 kallsyms has a "feature" where it unpacks the name into a string.
*If that string is reused before the caller expects it then the caller
*sees its string change without warning.

kallsyms_lookup always uses the buffer passed to it in the case the
symbol is a kernel symbol, as opposed to a module symbol, and so it is
not responsible for the buffer.

So this probably only happens when a module symbol is returned directly
from its symbol table, and then the module is unloaded (or something
like that).

Later there is another comment:
* Another 2.6 kallsyms "feature". Sometimes the sym_name is
* set but the buffer passed into kallsyms_lookup is not used,
* so it contains garbage.

It seems to be the same problem. If we modify kallsyms_lookup to always
use the buffer passed, even if the symbol comes from a module, maybe we
could solve both problems with just one change.

On the downside, a caller that just wants to print the name, would pay
an unnecessary string copy.

On the upside, this would make the interface more coherent with standard
C functions like strcpy, where the buffer passed is always the buffer
returned.

So, is it worth the change?

--
Paulo Marques - www.grupopie.com

"A journey of a thousand miles begins with a single step."
Lao-tzu, The Way of Lao-tzu

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:09    [W:0.022 / U:0.868 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site