[PATCH] 7: 2.5.29-mmap

From: Russell King (rmk@arm.linux.org.uk)
Date: Sat Aug 03 2002 - 13:16:17 EST

This patch has been verified to apply cleanly to 2.5.30

This patch goes back almost 2 years. First sent on: 30 September 2000
Ignored every time.

The following patch is required so that munmap(0x8000, *) does not cause
ARM kernels to crash. The problem is that the machine vectors are at
virtual address 0. Unfortunately, when free_pgtables() is called, it
clears first level page tables starting at 0 in this case, and takes
out the machine vectors. This then results in an unrecoverable hang.

We already have FIRST_USER_PGD_NR to define the first entry in the pgd
which may be cleared, so we use this to clamp "start_index"
appropriately. The following patch does this. Tested on ARM.

 mm/mmap.c | 2 ++
 1 files changed, 2 insertions

diff -urN orig/mm/mmap.c linux/mm/mmap.c
--- orig/mm/mmap.c Sat Jul 27 13:55:25 2002
+++ linux/mm/mmap.c Sat Jul 27 14:14:43 2002
@@ -888,6 +888,8 @@
          * old method of shifting the VA >> by PGDIR_SHIFT doesn't work.
         start_index = pgd_index(first);
+ if (start_index < FIRST_USER_PGD_NR)
+ start_index = FIRST_USER_PGD_NR;
         end_index = pgd_index(last);
         if (end_index > start_index) {
                 clear_page_tables(tlb, start_index, end_index - start_index);

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This archive was generated by hypermail 2b29 : Wed Aug 07 2002 - 22:00:22 EST