Re: /proc/kallsyms broken in 2.6.26-rc1-git6

From: Sam Ravnborg
Date: Mon May 19 2008 - 14:10:53 EST


On Tue, May 13, 2008 at 11:54:37AM +0200, Andi Kleen wrote:
> > I expect it to be a toolchain issue. Andi is often running with gcc versions
> > that are very new (fresh from svn maybe). I dunno about binutils.
>
> No actually that's a pretty old version from SUSE 10.2
>
> gcc-4.1.3-29
> binutils-2.17.50.0.5-21
>
> This means i've been recently trying to get the x86-64 kernel to work
> with the new gold linker from binutils mainline, but it's far from
> booting yet and was not used here.
>
> > To reproduce I would expect that a very recent gcc/binutils is needed.
> > Andi?
>
> Just a SUSE 10.2 toolchain. You can probably rpm2cpio it from any
> SUSE mirror.

I have just commit the following that should fix it.

Sam

commit aab34ac8582303ef57b792710fc5dd5991477475
Author: Sam Ravnborg <sam@xxxxxxxxxxxx>
Date: Mon May 19 20:07:58 2008 +0200

kbuild: filter away debug symbols from kernel symbols

Andi Kleen <andi@xxxxxxxxxxxxxx>
reported that he saw a lot of symbols like this:

0000000000000b24 N DW.aio.h.903a6d92.2
0000000000000bce N DW.task_io_accounting.h.8d8de327.0
0000000000000bec N DW.hrtimer.h.c23659c6.0

in his System.map / kallsyms output.

Simple solution is to skip all debugging
symbols (they are marked 'N').

Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: Paulo Marques <pmarques@xxxxxxxxxxxx>

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 5d20a2e..ad2434b 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -108,6 +108,9 @@ static int read_symbol(FILE *in, struct sym_entry *s)
/* exclude also MIPS ELF local symbols ($L123 instead of .L123) */
else if (str[0] == '$')
return -1;
+ /* exclude debugging symbols */
+ else if (stype == 'N')
+ return -1;

/* include the type field in the symbol name, so that it gets
* compressed together */
diff --git a/scripts/mksysmap b/scripts/mksysmap
index 4390fab..6e133a0 100644
--- a/scripts/mksysmap
+++ b/scripts/mksysmap
@@ -32,6 +32,7 @@
# For System.map filter away:
# a - local absolute symbols
# U - undefined global symbols
+# N - debugging symbols
# w - local weak symbols

# readprofile starts reading symbols when _stext is found, and
@@ -40,5 +41,5 @@
# so we just ignore them to let readprofile continue to work.
# (At least sparc64 has __crc_ in the middle).

-$NM -n $1 | grep -v '\( [aUw] \)\|\(__crc_\)\|\( \$[adt]\)' > $2
+$NM -n $1 | grep -v '\( [aNUw] \)\|\(__crc_\)\|\( \$[adt]\)' > $2

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