Paulo, On Tue, Sep 25, 2007 at 05:21:06PM +0100, Paulo Marques wrote: > Stephane Eranian wrote: > >Hello, > > Hi, Stephane > > >Many monitoring tools use /proc/kallsyms to build a symbol table for the > >kernel. > >This technique has the advantage that it does not require root privileges, > >nor > >an up-to-date /boot/System.map, nor a decompressed kernel in /boot. > > > >The problem is that /proc/kallsyms does not report the size of the symbols. > >Yet, the information is available in the kernel as it is used by functions > >such as __print_symbol(). Having the size is useful to correlate the address > >obtained > >is a sample with a symbol name. Most tools use an approximation which > >assumes > >symbols are contiguous to estimate the size. > > That is actually what the kernel does internally, too. It does not keep > the size of the symbol, but tries to guess it from the address of the > next non-aliased symbol. > > Since the addresses are sorted, this works fine most of the time. This > is done to reduce the size used by the symbol table in the running kernel. > > Just take a look at "get_symbol_pos" in kernel/kallsyms.c and > "get_ksymbol" in kernel/module.c to see exactly how this is done > Ok. Then we cannot really do better.
Also thank you for alerting me on the aliased symbols. I have modified my user code to only keep the first symbol. Thanks for you help. -- -Stephane - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/