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

On Wed, 14 Mar 2007 17:52:01 +0000 (UTC) Leroy van Logchem <leroy.vanlogchem@xxxxxxxxxx> wrote:
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.

Thanks. Please always do reply-to-all. Cc's restored (and added..)

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

a1f3bb9ae4497a2ed3eac773fd7798ac33a0371f is first bad commit
commit a1f3bb9ae4497a2ed3eac773fd7798ac33a0371f
Author: Roland McGrath <roland@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

: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

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    ... I'll try to do my first bi-sect today. ... after 13 compiles this commit was found: ... returns to the vma address rather than the fixmap address, ... This patch makes CONFIG_COMPAT_VDSO disable the real vma and use the fixmap ...
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