Hi!
Why then it works on 3.4-STABLE (booting without loader(8) and
having kvm(3) programs like pstat(8) and top(1) working).
What makes a difference here?
On Sun, Feb 06, 2000 at 09:38:41PM -0500, Garrett Wollman wrote:
> <<On Mon, 7 Feb 2000 00:25:51 +0200, Ruslan Ermilov <[EMAIL PROTECTED]> said:
>
> > If I boot with loader(8), everything is ok.
> > Ideas?
>
> loader loads the kernel symbol table; boot2 does not.
>
> -GAWollman
On Mon, Feb 07, 2000 at 03:22:36PM +1100, Bruce Evans wrote:
> On Mon, 7 Feb 2000, Ruslan Ermilov wrote:
>
> > If I boot the system without loader(8), e.g. with /boot.config=kernel,
> > or by interrupting boot blocks and typing /kernel, swapinfo(8) fails:
> >
> > swapinfo: undefined symbol: _numvnodes
>
> This is because the elf format puts static symbols in an out-of-the-way
> section, and the boot2 stage of the bootstrap loads sections naively.
> Static symbols end up in a place where the kernel linker can't find
> them. `numvnodes' is a static symbol... Global symbols are found
> correctly.
>
> This bug has affected ddb for more than a year. I don't believe in
> or use loader(8), and have "fixed" the problem in ddb by not using
> the kernel linker for ddb symbol lookup. This also fixes the
> nonexistence of ddb symbols on booting with -d.
>
> Bruce
On Mon, Feb 07, 2000 at 10:14:29PM +0800, Peter Wemm wrote:
> Garrett Wollman wrote:
> > <<On Mon, 7 Feb 2000 00:25:51 +0200, Ruslan Ermilov <[EMAIL PROTECTED]> said:
> >
> > > If I boot with loader(8), everything is ok.
> > > Ideas?
> >
> > loader loads the kernel symbol table; boot2 does not.
> >
> > -GAWollman
>
> More to the point, a non-stripped kernel has *two* symbol tables. One that
> has the global symbols and is used for dynamic linking, and the other that
> has the debugging info in it including static symbols. loader(8) goes to a
> great deal of trouble to get the second table - it's very hard to get it
> when reading from a zlib decompression stream that can't be seek'ed. The ELF
> format defines a convenient 'load segment' table which defines (usually)
> two chunks of the file to be loaded into memory and at what addresses. The
> verbose symbol table is not part of this, but the global table is and we get
> it for free.
>
> Anyway, the correct fix is to make numvnodes global or to change it to a
> sysctl. Nothing that is referred to by the common libkvm applications
> should be static - this warning has been given before. running a strip on /
> kernel has the same effect as using boot2 - only global symbols are
> accessible.
>
> Cheers,
> -Peter
--
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