Messages in this thread Patch in this message | | | From | Dan Smith <> | Subject | [PATCH] Ensure that walk_page_range()'s start and end are page-aligned | Date | Fri, 10 Feb 2012 11:39:56 -0800 |
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The inner function walk_pte_range() increments "addr" by PAGE_SIZE after each pte is processed, and only exits the loop if the result is equal to "end". Current, if either (or both of) the starting or ending addresses passed to walk_page_range() are not page-aligned, then we will never satisfy that exit condition and begin calling the pte_entry handler with bad data.
To be sure that we will land in the right spot, this patch checks that both "addr" and "end" are page-aligned in walk_page_range() before starting the traversal.
Signed-off-by: Dan Smith <danms@us.ibm.com> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/pagewalk.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/mm/pagewalk.c b/mm/pagewalk.c index 2f5cf10..9242bfc 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -196,6 +196,8 @@ int walk_page_range(unsigned long addr, unsigned long end, if (addr >= end) return err; + VM_BUG_ON((addr & ~PAGE_MASK) || (end & ~PAGE_MASK)); + if (!walk->mm) return -EINVAL; -- 1.7.9
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