> Anyway, insmod detects a "versioned" kernel by looking for a symbol
> "Using_Versions", defined in kernel/ksyms.c. The symbol is not in
> /proc/ksyms, /System.map nor anywhere else in the source tree. insmod
> can't find it either.
Yes, this has been broken since 2.1.21 (not 121, *21*), released in
January, 1997. I noticed it in December 1997. Here's a reprint of
the bug report I filed with linux-kernel. All the information in it is
still current.
Specifically, 2.1.21 changed Rules.make so that LX_OBJS and OX_OBJS
no longer get compiled with -DMODVERSIONS. So kernel/ksyms.c never
turns on 'Using_Versions'. Every kernel built since 2.1.21 appears
to insmod as a non-versioned kernel.
As soon as someone fixes this, two years of accumulated untested
CONFIG_MODVERSIONS funkiness will spring out.
Michael Elizabeth Chastain
<mailto:mec@shout.net>
"love without fear"
===
From mec Mon Dec 29 23:25:46 1997
To: linux-kernel@vger.rutgers.edu
Subject: CONFIG_MODVERSIONS bug
Hello kernel hackers,
I think I've found a long-standing bug with CONFIG_MODVERSIONS.
Take a look at this paragraph from kernel/ksyms.c, 2.1.76:
#ifdef MODVERSIONS
const struct module_symbol __export_Using_Versions
__attribute__((section("__ksymtab"))) = {
1 /* Version version */, "Using_Versions"
};
#endif
The problem is that MODVERSIONS is defined only when compiling *modules*.
It's not defined when compiling kernel/ksyms.c because kernel/ksyms.c
is part of the resident kernel.
This construction has been in the kernel for a long time. It's also
in 2.1.76, 2.1.50, 2.1.32, 2.1.16, 2.0.33, and 2.0. Back in the 2.0.XX
kernels, Rules.make said -DMODVERSIONS for $(LX_OBJS) and $(OX_OBJS).
But it doesn't any more. And it probably shouldn't. The right fix
is probably to change MODVERSIONS above to CONFIG_MODVERSIONS.
I have no patch for this one because I've got enough patches in progress
already.
How I found this: I was chasing some other potential bugs in insmod
2.1.71 when I noticed that new_get_kernel_symbols returned 0. Then I
checked /proc/ksyms, and there was no "Using_Versions" there.
Michael Chastain
<mailto:mec@shout.net>
"love without fear"
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