> Under linux-2.4.3-pre6 compiled for SMP, loading agpgart.o
>hangs the system in remap_area_pages (arch/i386/mm/ioremap.c) at
>the call to spin_lock(&init_mm.page_table_lock), which is not in 2.4.2.
[...]
> agp_backend_initialize
> agp_generic_create_gatt_table
> io_remap_nocache
> __ioremap
> remap_area_pages
[...]
> I'm rebuilding the kernel now with a modified spin_lock()
>routine that should tell me who acquired the lock previously [...]
In case anyone is interested, the conflicting lock of
init_mm.page_table_lock was acquired in line 1318 of mm/memory.c,
in pte_alloc.
One way that this might be happening is that it looks like
no page_table_lock is every acquired by vmalloc, which results in
the following call graph:
vmalloc
__vmalloc
vmalloc_area_pages
alloc_area_pmd
pte_alloc ...which assumes (here incorrectly) that
mm->page_table_lock is held, and sometimes releases
and reacquires mm->page_table_lock.
I will attempt to analyze this further tomorrow if nobody
beats me to it.
Adam J. Richter __ ______________ 4880 Stevens Creek Blvd, Suite 104
adam@yggdrasil.com \ / San Jose, California 95129-1034
+1 408 261-6630 | g g d r a s i l United States of America
fax +1 408 261-6631 "Free Software For The Rest Of Us."
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