lkml.org 
[lkml]   [2005]   [Jun]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 1/2] mbind: fix verify_pages pte_page
Strict mbind's check that pages already mapped are on right node has been
using pte_page without checking if pfn_valid, and without page_table_lock
to prevent spurious failures when try_to_unmap_one intervenes between the
pte_present and the pte_page.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
---

mm/mempolicy.c | 19 ++++++++++++++-----
1 files changed, 14 insertions(+), 5 deletions(-)

--- 2.6.12-rc6/mm/mempolicy.c 2005-05-25 18:09:21.000000000 +0100
+++ linux/mm/mempolicy.c 2005-06-04 20:41:55.000000000 +0100
@@ -242,6 +242,9 @@ static int
verify_pages(struct mm_struct *mm,
unsigned long addr, unsigned long end, unsigned long *nodes)
{
+ int err = 0;
+
+ spin_lock(&mm->page_table_lock);
while (addr < end) {
struct page *p;
pte_t *pte;
@@ -268,17 +271,23 @@ verify_pages(struct mm_struct *mm,
}
p = NULL;
pte = pte_offset_map(pmd, addr);
- if (pte_present(*pte))
- p = pte_page(*pte);
+ if (pte_present(*pte)) {
+ unsigned long pfn = pte_pfn(*pte);
+ if (pfn_valid(pfn))
+ p = pfn_to_page(pfn);
+ }
pte_unmap(pte);
if (p) {
unsigned nid = page_to_nid(p);
- if (!test_bit(nid, nodes))
- return -EIO;
+ if (!test_bit(nid, nodes)) {
+ err = -EIO;
+ break;
+ }
}
addr += PAGE_SIZE;
}
- return 0;
+ spin_unlock(&mm->page_table_lock);
+ return err;
}

/* Step 1: check the range */
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2005-06-06 21:54    [W:0.045 / U:0.268 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site