Re: [Bug 8040] Hang before INIT when CONFIG_HIGHMEM4G=y [Fix CONFIG_COMPAT_VDSO] <- Bad

[Leroy van Logchem <leroy.vanlogchem@wldelft.nl>]

Leroy van Logchem <leroy.vanlogchem <at> wldelft.nl> writes:

> 
> > > None whatsoever.  Three people are reporting this and it's a drop-dead
> > > showstopper for a 2.6.21 release so we just have to wait until someone
> > > wakes up and thinks about it.
> 
> The topic should be "when CONFIG_HIGHMEM64G=y" imo.
> 
> I'll try to do my first bi-sect today.

Bisecting went well, after 13 compiles this commit was found:

a1f3bb9ae4497a2ed3eac773fd7798ac33a0371f is first bad commit
commit a1f3bb9ae4497a2ed3eac773fd7798ac33a0371f
Author: Roland McGrath <roland@redhat.com>
Date:   Fri Jan 26 00:56:46 2007 -0800

    [PATCH] Fix CONFIG_COMPAT_VDSO
    
    I wouldn't mind if CONFIG_COMPAT_VDSO went away entirely.  But if it's there,
    it should work properly.  Currently it's quite haphazard: both real vma and
    fixmap are mapped, both are put in the two different AT_* slots, sysenter
    returns to the vma address rather than the fixmap address, and core dumps yet
    are another story.
    
    This patch makes CONFIG_COMPAT_VDSO disable the real vma and use the fixmap
    area consistently.  This makes it actually compatible with what the old vdso
    implementation did.
    
    Signed-off-by: Roland McGrath <roland@redhat.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Paul Mackerras <paulus@samba.org>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Andi Kleen <ak@suse.de>
    Signed-off-by: Andrew Morton <akpm@osdl.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

:040000 040000 802ab3366a651ecba28c8677fa84a9f7c506392b
f44adc4dcdab733e5965b68ccd0d643f0a550a80 M      arch
:040000 040000 be1e217152d8b3fcd05f09aa2b3f4f9dcb8208aa
46cc86427e861350dd3fef9469474c55119f27ce M      include

I had both CONFIG_COMPAT_VDSO=y and CONFIG_HIGHMEM64G=y configured.
Using a 4GB Supermicro 7044 SMP dual Xeon. Details upon request.

--
Leroy