Messages in this thread Patch in this message | | | Subject | [PATCH] futex: fix reference leak | From | Peter Zijlstra <> | Date | Mon, 09 Feb 2009 19:26:15 +0100 |
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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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