On Sat, 07 Apr 2007 19:30:14 +1000 Nick Piggin <[EMAIL PROTECTED]> wrote:
> Eric Dumazet wrote: > > > > - Current mm code have a problem with 64bit futexes, as spoted by Nick : > > > > get_futex_key() does a check against sizeof(u32) regardless of futex being > > 64bits or not. > > So it is possible a 64bit futex spans two pages of memory... > > I had to change get_futex_key() prototype to be able to do a correct test. > > I wonder if it should be encfocing alignment to keep in on 1 page? I believe I just did that :) Before the patch : Alignment was only 4 bytes for all futexes, but some user app could trigger a kernel bug (since one 64bit futex could sit on two different pages, so possible separate vmas, so the inode refcounting was wrong, and access_ok did not a correct check) After the patch : Alignment is 8 bytes for 64 bit futexes, 4 bytes for 32bit futexes. All futexes are contrained to be in one single page. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
