Re: Fatal Oops on boot with 2.4.0testX and recent GCC snapshots

[Andreas Franck <afranck@gmx.de>]

Hello Mike, hello linux-kernel hackers,

Mike Galbraith wrote:
> I wouldn't (not going to here;) spend a lot of time on it.  The compiler
> has problems.  It won't build glibc-2.2, and chokes horribly on ipchains.

Maybe, but after having spent several hours debugging now, I think it was 
worth it: I am almost sure this is not a gcc bug, but a nasty race condition 
involving the semaphore handling bdflush_init. 

I figured out by spilling some printk's around in bdflush_init, which made 
the bug magically disappear, what wasn't what I intended - but which gave me 
a clearer impression of what's going on.

It seems that whyever, the cause for this failure is actually the down(sem) 
call on a not yet up()'ed semaphore, and this is where it starts to get ugly.


-- 
->>>----------------------- Andreas Franck --------<<<-
---<<<---- Andreas.Franck@post.rwth-aachen.de --->>>---
->>>---- Keep smiling! ----------------------------<<<-
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