On Sun, Mar 27, 2005 at 12:42:56AM +1100, Nick Piggin wrote:
> OK, thanks that would be good. You could well be right in your analysis.
> May I suggest a possible avenue of investigation:
Yes, this patch seems to also be required, otherwise I see:
free_pgtables : floor 40015000 ceiling 4001b000
free_pgd_range: floor 40015000 ceiling 4001b000 addr 40015000 end 40016000
free_pgtables : floor 40015000 ceiling 4001b000
free_pgd_range: floor 40015000 ceiling 4001b000 addr 40015000 end 40016000
free_pgtables : floor 40015000 ceiling 4001b000
free_pgd_range: floor 40015000 ceiling 4001b000 addr 40015000 end 40016000
free_pgtables : floor 00000000 ceiling 00000000
free_pgd_range: floor 00000000 ceiling 40000000 addr 00008000 end 0001d000
free_pud_range: floor 00000000 ceiling 40000000 addr 00000000 end 00200000
free_pmd_range: floor 00000000 ceiling 40000000 addr 00000000 end 00200000
free_pgd_range: floor 00000000 ceiling bef4e000 addr 40000000 end 4012d000
free_pud_range: floor 00000000 ceiling bef4e000 addr 40000000 end 40200000
free_pmd_range: floor 00000000 ceiling bef4e000 addr 40000000 end 40200000
free_pgd_range: floor 00000000 ceiling 00000000 addr bef4e000 end bef63000
free_pud_range: floor 00000000 ceiling 00000000 addr bee00000 end bf000000
free_pmd_range: floor 00000000 ceiling 00000000 addr bee00000 end bf000000
exit_mmap: nr_ptes -1
The above is with my fix to ARMs get_pgd_slow, which shows that we
accidentally freed the first entry in the L1 page table. With my
fix and your patch, low-vectored ARMs work again.
I don't think it'll be invasive to push my get_pgd_slow() fix before
these freepgt patches appear. For the record, this is the patch I'm
using at present. With a bit more effort, I could probably eliminate
pmd_alloc (and therefore the unnecessary spinlocking) here.
diff -up -x BitKeeper -x ChangeSet -x SCCS -x _xlk -x *.orig -x *.rej
orig/arch/arm/mm/mm-armv.c linux/arch/arm/mm/mm-armv.c
--- orig/arch/arm/mm/mm-armv.c Sat Mar 19 11:20:01 2005
+++ linux/arch/arm/mm/mm-armv.c Sat Mar 26 15:51:57 2005
@@ -160,6 +160,8 @@ pgd_t *get_pgd_slow(struct mm_struct *mm
init_pgd = pgd_offset_k(0);
if (!vectors_high()) {
+ struct page *new;
+
/*
* This lock is here just to satisfy pmd_alloc and pte_lock
*/
@@ -170,12 +172,16 @@ pgd_t *get_pgd_slow(struct mm_struct *mm
* contains the machine vectors.
*/
new_pmd = pmd_alloc(mm, new_pgd, 0);
+ spin_unlock(&mm->page_table_lock);
if (!new_pmd)
goto no_pmd;
- new_pte = pte_alloc_map(mm, new_pmd, 0);
- if (!new_pte)
+ new = pte_alloc_one(mm, 0);
+ if (!new)
goto no_pte;
+ inc_page_state(nr_page_table_pages);
+ pmd_populate(mm, new_pmd, new);
+ new_pte = pte_offset_map(new_pmd, 0);
init_pmd = pmd_offset(init_pgd, 0);
init_pte = pte_offset_map_nested(init_pmd, 0);
@@ -197,16 +203,9 @@ pgd_t *get_pgd_slow(struct mm_struct *mm
return new_pgd;
no_pte:
- spin_unlock(&mm->page_table_lock);
pmd_free(new_pmd);
- free_pages((unsigned long)new_pgd, 2);
- return NULL;
-
no_pmd:
- spin_unlock(&mm->page_table_lock);
free_pages((unsigned long)new_pgd, 2);
- return NULL;
-
no_pgd:
return NULL;
}
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 Serial core
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