diff options
| author | Sonny Rao <sonnyrao@us.ibm.com> | 2009-07-10 18:13:13 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-07-19 20:38:50 -0700 |
| commit | eadc4345f93b857cbf8c63400ea0a7ed9b6431a2 (patch) | |
| tree | 8ffafc9bfd16d794731bf5739d84ad4ab4b3a57a | |
| parent | 434f5f9696e76352c4e23b3fa99881e87149da66 (diff) | |
futexes: Fix infinite loop in get_futex_key() on huge page
commit ce2ae53b750abfaa012ce408e93da131a5b5649b upstream.
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: 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -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 f2cee4b24c51..4d973bde8533 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -241,6 +241,7 @@ again: if (err < 0) return err; + page = compound_head(page); lock_page(page); if (!page->mapping) { unlock_page(page); |