missing symbol do_softirq in net moduels for pre-2

missing symbol do_softirq in net moduels for pre-2

[Ed Tomlinson]

Hi,

Built -pre2 and noticed most of the modules in net/* are getting
a missing symbol for do_softirq.  

Have I messed up, or is there a real error?

Ed Tomlinson <tomlins@cam.org>

Re: missing symbol do_softirq in net moduels for pre-2

[Keith Owens]

On Sat, 9 Jun 2001 11:07:52 -0400, 
Ed Tomlinson <tomlins@cam.org> wrote:
>Built -pre2 and noticed most of the modules in net/* are getting
>a missing symbol for do_softirq.  

http://www.tux.org/lkml/#s8-8

Re: missing symbol do_softirq in net moduels for pre-2

[Thomas Langås]

Keith Owens:
> >Built -pre2 and noticed most of the modules in net/* are getting
> >a missing symbol for do_softirq.  
> http://www.tux.org/lkml/#s8-8

I got the same error on -pre1, and tried the info in the link, didn't help:

root@test4:/usr/src# depmod -ae
depmod: *** Unresolved symbols in /lib/modules/2.4.6-pre1/kernel/net/ipv4/netfilter/ip_tables.o
depmod:         do_softirq
depmod: *** Unresolved symbols in /lib/modules/2.4.6-pre1/kernel/net/ipv4/netfilter/ipt_LOG.o
depmod:         do_softirq

Am I missing something in my .config, or is there something else that's
wrong? Any clues to where I should look?

-- 
-Thomas

Re: missing symbol do_softirq in net moduels for pre-2

[Wayne Whitney]

In mailing-lists.linux-kernel, Keith Owens wrote:

> On Sat, 9 Jun 2001 Ed Tomlinson <tomlins@cam.org> wrote:
>
> > Built -pre2 and noticed most of the modules in net/* are getting 
> > a missing symbol for do_softirq.  
>
> http://www.tux.org/lkml/#s8-8

Hmm, I don't think this is it--I'm seeing the same thing, and I have
tried 'make mrproper'.  All symbols are getting versionated except
certain calls to do_softirq() in, e.g., sunrpc.o and the iptables
modules.

I looked into this, and I believe the problem is due to 2.4.6-pre2's
change to the i386 local_bh_enable() macro--the C version has been
replaced with an assembly language version that does "call
do_doftirq;".  Perhaps this function call from the assembly language
version does not get versionated?  

Cheers, Wayne

Re: missing symbol do_softirq in net moduels for pre-2

[Ed Tomlinson]

On Saturday 09 June 2001 12:56, Wayne Whitney wrote:
> In mailing-lists.linux-kernel, Keith Owens wrote:
> > On Sat, 9 Jun 2001 Ed Tomlinson <tomlins@cam.org> wrote:
> > > Built -pre2 and noticed most of the modules in net/* are getting
> > > a missing symbol for do_softirq.
> >
> > http://www.tux.org/lkml/#s8-8
>
> Hmm, I don't think this is it--I'm seeing the same thing, and I have
> tried 'make mrproper'.  All symbols are getting versionated except
> certain calls to do_softirq() in, e.g., sunrpc.o and the iptables
> modules.
>
> I looked into this, and I believe the problem is due to 2.4.6-pre2's
> change to the i386 local_bh_enable() macro--the C version has been
> replaced with an assembly language version that does "call
> do_doftirq;".  Perhaps this function call from the assembly language
> version does not get versionated?

In my case its off a clean tree patched with lvm, ide patches, dma timeout
retry patch and reiserfs fixes.  Did we not have a problem a while back
in ac with versioned symbols in assembly?

Ed Tomlinson

Re: missing symbol do_softirq in net moduels for pre-2

[Keith Owens]

On Sat, 9 Jun 2001 18:56:24 +0200, 
=?iso-8859-1?Q?Thomas_Lang=E5s?= <tlan@stud.ntnu.no> wrote:
>Keith Owens:
>> >Built -pre2 and noticed most of the modules in net/* are getting
>> >a missing symbol for do_softirq.  
>> http://www.tux.org/lkml/#s8-8
>
>I got the same error on -pre1, and tried the info in the link, didn't help:
>
>root@test4:/usr/src# depmod -ae
>depmod: *** Unresolved symbols in /lib/modules/2.4.6-pre1/kernel/net/ipv4/netfilter/ip_tables.o
>depmod:         do_softirq

It was missing in 6-pre1.  It should have been fixed in 6-pre2.

Re: missing symbol do_softirq in net moduels for pre-2

[Ed Tomlinson]

On Saturday 09 June 2001 13:04, Keith Owens wrote:
> On Sat, 9 Jun 2001 18:56:24 +0200,
>
> =?iso-8859-1?Q?Thomas_Lang=E5s?= <tlan@stud.ntnu.no> wrote:
> >Keith Owens:
> >> >Built -pre2 and noticed most of the modules in net/* are getting
> >> >a missing symbol for do_softirq.
> >>
> >> http://www.tux.org/lkml/#s8-8
> >
> >I got the same error on -pre1, and tried the info in the link, didn't
> > help:
> >
> >root@test4:/usr/src# depmod -ae
> >depmod: *** Unresolved symbols in
> > /lib/modules/2.4.6-pre1/kernel/net/ipv4/netfilter/ip_tables.o depmod:    
> >     do_softirq
>
> It was missing in 6-pre1.  It should have been fixed in 6-pre2.

The fix to export ksyms for do_softirq is _in_ pre2...  its just not working.

from ksyms in pre2:
/* software interrupts */
EXPORT_SYMBOL(tasklet_hi_vec);
EXPORT_SYMBOL(tasklet_vec);
EXPORT_SYMBOL(bh_task_vec);
EXPORT_SYMBOL(init_bh);
EXPORT_SYMBOL(remove_bh);
EXPORT_SYMBOL(tasklet_init);
EXPORT_SYMBOL(tasklet_kill);
EXPORT_SYMBOL(__run_task_queue);
EXPORT_SYMBOL(do_softirq);
EXPORT_SYMBOL(tasklet_schedule);
EXPORT_SYMBOL(tasklet_hi_schedule);

in the arch code for softirq we now have:

+#define local_bh_enable()                                              \
+do {                                                                   \
+       unsigned int *ptr = &local_bh_count(smp_processor_id());        \
+                                                                       \
+       if (!--*ptr)                                                    \
+               __asm__ __volatile__ (                                  \
+                       "cmpl $0, -8(%0);"                              \
+                       "jnz 2f;"                                       \
+                       "1:;"                                           \
+                                                                       \
+                       ".section .text.lock,\"ax\";"                   \
+                       "2: pushl %%eax; pushl %%ecx; pushl %%edx;"     \
+                       "call do_softirq;"

What has to happen to get assembly code to version the symbol?

Ed Tomlinson

Re: missing symbol do_softirq in net moduels for pre-2

[Wayne Whitney]

On 09 June 2001, Ed Tomlinson wrote:

>in the arch code for softirq we now have:
>
>+#define local_bh_enable()                                              \
>+do {                                                                   \
>+       unsigned int *ptr = &local_bh_count(smp_processor_id());        \
>+                                                                       \
>+       if (!--*ptr)                                                    \
>+               __asm__ __volatile__ (                                  \
>+                       "cmpl $0, -8(%0);"                              \
>+                       "jnz 2f;"                                       \
>+                       "1:;"                                           \
>+                                                                       \
>+                       ".section .text.lock,\"ax\";"                   \
>+                       "2: pushl %%eax; pushl %%ecx; pushl %%edx;"     \
>+                       "call do_softirq;"
>
>What has to happen to get assembly code to version the symbol?

I have verified that the versioning of the do_softirq symbol above is
the source of the problems in 2.4.6-pre2: I made two copies of the
local_bh_enable macro, one with the versioning hash explicitly
appended to the symbol, and chose between with #ifdef MODULE.
Everything works fine now.

Of course, this is ugly, ugly, ugly, so hopefully someone will answer
Ed's question as to the correct way of doing this.

Cheers, Wayne

Re: missing symbol do_softirq in net moduels for pre-2

[Keith Owens]

On Sat, 9 Jun 2001 11:13:46 -0700, 
Wayne Whitney <whitney@math.berkeley.edu> wrote:
>I have verified that the versioning of the do_softirq symbol above is
>the source of the problems in 2.4.6-pre2

Resend, the first patch never appeared.  The problem is the call to
do_softirq inside an asm string where cpp cannot convert it.  The
correct fix is toe xpose do_softirq so cpp can convert it then map to a
string and concatenate with teh asm string.  But that requires ugly
helper macros, a cleaner fix is:

Against 2.4.6-pre2.  Note: you must run make mrproper after applying
this patch.

Index: 6-pre2.1/kernel/ksyms.c
--- 6-pre2.1/kernel/ksyms.c Sat, 09 Jun 2001 11:25:53 +1000 kaos (linux-2.4/j/46_ksyms.c 1.1.2.2.1.1.2.1.1.8.2.1.2.1 644)
+++ 6-pre2.1(w)/kernel/ksyms.c Sun, 10 Jun 2001 03:36:12 +1000 kaos (linux-2.4/j/46_ksyms.c 1.1.2.2.1.1.2.1.1.8.2.1.2.1 644)
@@ -536,7 +536,7 @@ EXPORT_SYMBOL(remove_bh);
 EXPORT_SYMBOL(tasklet_init);
 EXPORT_SYMBOL(tasklet_kill);
 EXPORT_SYMBOL(__run_task_queue);
-EXPORT_SYMBOL(do_softirq);
+EXPORT_SYMBOL_NOVERS(do_softirq);
 EXPORT_SYMBOL(tasklet_schedule);
 EXPORT_SYMBOL(tasklet_hi_schedule);