Martin Blapp wrote:
>
> Hi Alan,
>
> This commit makes my box crash with HEAD at startup. Please back it out
> and investige why it happens. I'm pretty sure that it happens for
> RELENG_6 too.
>
The assertion that fails for you under HEAD does not exist in RELENG_6.
Have you seen a different assertion failure or crash in RELENG_6 since
this patch was applied there?
I will discuss this with re@.
Regards,
Alan
>
>
> Martin Blapp, <mb@imp.ch> <mbr@FreeBSD.org>
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>
> On Wed, 27 Sep 2006, Alan Cox wrote:
>
>> alc 2006-09-27 18:10:16 UTC
>>
>> FreeBSD src repository
>>
>> Modified files: (Branch: RELENG_6)
>> sys/amd64/amd64 pmap.c
>> sys/i386/i386 pmap.c
>> Log:
>> MFC
>> Correct a very old and very obscure bug: vmspace_fork() calls
>> pmap_copy() if the mapping is VM_INHERIT_SHARE. Suppose the mapping
>> is also wired. vmspace_fork() clears the wiring attributes in the vm
>> map entry but pmap_copy() copies the PG_W attribute in the PTE. I
>> don't think this is catastrophic. It blocks pmap_remove_pages() from
>> destroying the mapping and corrupts the pmap's wiring count.
>>
>> This revision fixes the problem by changing pmap_copy() to clear the
>> PG_W attribute.
>>
>> Approved by: re (mux)
>>
>> Revision Changes Path
>> 1.516.2.8 +4 -3 src/sys/amd64/amd64/pmap.c
>> 1.523.2.8 +5 -3 src/sys/i386/i386/pmap.c
>>