diff options
| author | Sonny Rao <sonnyrao@us.ibm.com> | 2009-07-10 18:13:13 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-07-11 12:40:44 +0200 |
| commit | ce2ae53b750abfaa012ce408e93da131a5b5649b (patch) | |
| tree | 7d380e51a49ad40fc08044ed8050243080280273 | |
| parent | f00caa76297a534e30c3ec85382fbc3fd0dcbc69 (diff) | |
futexes: Fix infinite loop in get_futex_key() on huge page
get_futex_key() can infinitely loop if it is called on a
virtual address that is within a huge page but not aligned to
the beginning of that page. The call to get_user_pages_fast
will return the struct page for a sub-page within the huge page
and the check for page->mapping will always fail.
The fix is to call compound_head on the page before checking
that it's mapped.
Signed-off-by: Sonny Rao <sonnyrao@us.ibm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
Cc: anton@samba.org
Cc: rajamony@us.ibm.com
Cc: speight@us.ibm.com
Cc: mstephen@us.ibm.com
Cc: grimm@us.ibm.com
Cc: mikey@ozlabs.au.ibm.com
LKML-Reference: <20090710231313.GA23572@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/futex.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 794c862125f..0672ff88f15 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -247,6 +247,7 @@ again: if (err < 0) return err; + page = compound_head(page); lock_page(page); if (!page->mapping) { unlock_page(page); |