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

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Date:	Mon, 19 May 2008 20:11:18 +0200
From:	Sam Ravnborg <sam@...nborg.org>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	Cyrill Gorcunov <gorcunov@...il.com>,
	Paulo Marques <pmarques@...popie.com>,
	Alexey Dobriyan <adobriyan@...il.com>,
	linux-kernel@...r.kernel.org
Subject: Re: /proc/kallsyms broken in 2.6.26-rc1-git6

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@...nborg.org>
Date:   Mon May 19 20:07:58 2008 +0200

    kbuild: filter away debug symbols from kernel symbols
    
    Andi Kleen <andi@...stfloor.org>
    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@...nborg.org>
    Cc: Paulo Marques <pmarques@...popie.com>

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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