Bug 29487 - Incorrectly Compiled 2.4.2 kernel
Incorrectly Compiled 2.4.2 kernel
Status: CLOSED WORKSFORME
Product: Red Hat Linux
Classification: Retired
Component: gcc (Show other bugs)
7.1
i386 Linux
medium Severity medium
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Assigned To: Jakub Jelinek
David Lawrence
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Depends On:
Blocks:
  Show dependency treegraph
 
Reported: 2001-02-25 18:58 EST by Daryll
Modified: 2007-04-18 12:31 EDT (History)
1 user (show)

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Fixed In Version:
Doc Type: Bug Fix
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Last Closed: 2001-02-26 18:57:19 EST
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Description Daryll 2001-02-25 18:58:36 EST
From Bugzilla Helper:
User-Agent: Mozilla/4.76 [en] (X11; U; Linux 2.4.1-0.1.9 i686)


In the 2.4.2 kernel udelay is a macro that checks if you are attempting to
pass a delay of >20000 and calls a non-existant a bad_udelay() function.
The wavelan_cs module in drivers/net/pcmcia makes multiple calls to udelay
but never with a value greater than 100.  Yet, the compiler is making the
calls to bad_udelay.

Reproducible: Always
Steps to Reproduce:
1. Compile the 2.4.2 kernel sources with no patches
2. nm -B /usr/src/linux/drivers/net/pcmcia/wavelan_cs.o | grep bad_udelay
3.
	

Actual Results:           U __bad_udelay


Expected Results:  Nothing
Comment 1 Jakub Jelinek 2001-02-26 05:30:45 EST
I remember fixing similar thing in gcc-2.96-72, are you sure you have say
2.96-75 or later?
If yes, can you please attach here wavelan_cs.i (add -save-temps -v options
to the gcc command which creates wavelan_cs.o) and also post full gcc command
line used? It maybe config related etc., by working on preprocessed output
we can be sure we're seeing the same thing. Thanks.
Comment 2 Jakub Jelinek 2001-02-26 07:45:45 EST
FYI I've just tried it and could not get __bad_udelay unresolved in any of
-march=i386, -march=i686, -march=k6 or -march=athlon. So, I really need your
feedback on this.
Comment 3 Daryll 2001-02-26 14:41:17 EST
I WAS able to reproduce it consistently. I even tried applying the redhat
patches to the wavelan driver to see if changing the function from inline to a
macro made it better. It didn't. Today I've redone the compile several times and
I can't make bad_udelay occur. Maybe there's an uninitialized variable somewhere
and I can't reproduce the circumstances.

Comment 4 Glen Foster 2001-02-26 18:57:15 EST
We (Red Hat) should really try to resolve this before next release.
Comment 5 Jakub Jelinek 2001-03-22 10:56:14 EST
If you are able to reproduce this, please reopen this bug.
Comment 6 Need Real Name 2001-04-16 15:13:08 EDT
This is reproducible with gcc 2.96-69.  According to the maintainers
of wavelan.c and include/asm-i386/delay.h it's a defect in that rev
of gcc where __builtin_constant_p() doesn't work.  2.96-69 is what's
currently on updates.redhat.com for 7.0.

How hard is it to get a newer gcc released as a 7.0 update?

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