Messages in this thread | | | Subject | Re: [PATCH] futex: fix reference leak | From | "Pallipadi, Venkatesh" <> | Date | Mon, 09 Feb 2009 10:53:15 -0800 |
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Yes. This patch fixes the problem on my system. With git, without the patch I see the same oops as before on reboot. With the patch, system reboots cleanly.
A minor typo in the patch + ret = -RESTART_RESTARTBLOCK; should be + ret = -ERESTART_RESTARTBLOCK;
Thanks, Venki
On Mon, 2009-02-09 at 10:26 -0800, Peter Zijlstra wrote: > Venki, does this perchance solve your issue with my futex patch? > > Darren, could you please have a look at this before Ingo pushes it out > to Linus? > > --- > Catalin noticed that (38d47c1b7075: futex: rely on > get_user_pages() for shared futexes) caused an mm_struct leak. > > Some tracing with the function graph tracer quickly pointed out that > futex_wait() has exit paths with unbalanced reference counts. > > Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> > --- > kernel/futex.c | 23 +++++++++++++++-------- > 1 files changed, 15 insertions(+), 8 deletions(-) > > diff --git a/kernel/futex.c b/kernel/futex.c > index f89d373..7b76c8e 100644 > --- a/kernel/futex.c > +++ b/kernel/futex.c > @@ -1284,18 +1284,23 @@ retry: > */ > > /* If we were woken (and unqueued), we succeeded, whatever. */ > - if (!unqueue_me(&q)) > - return 0; > - if (rem) > - return -ETIMEDOUT; > + if (!unqueue_me(&q)) { > + ret = 0; > + goto out_put_key; > + } > + if (rem) { > + ret = -ETIMEDOUT; > + goto out_put_key; > + } > > /* > * We expect signal_pending(current), but another thread may > * have handled it for us already. > */ > - if (!abs_time) > - return -ERESTARTSYS; > - else { > + if (!abs_time) { > + ret = -ERESTARTSYS; > + goto out_put_key; > + } else { > struct restart_block *restart; > restart = ¤t_thread_info()->restart_block; > restart->fn = futex_wait_restart; > @@ -1309,11 +1314,13 @@ retry: > restart->futex.flags |= FLAGS_SHARED; > if (clockrt) > restart->futex.flags |= FLAGS_CLOCKRT; > - return -ERESTART_RESTARTBLOCK; > + ret = -RESTART_RESTARTBLOCK; > + goto out_put_key; > } > > out_unlock_put_key: > queue_unlock(&q, hb); > +out_put_key: > put_futex_key(fshared, &q.key); > > out: > >
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