linux-kernel - [PATCH] RFC: futex fault handling and futex key references (NOT FOR INCLUSION)

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Message-ID: <20090109075148.2226.5222.stgit@Aeon>
Date:	Thu, 08 Jan 2009 23:52:17 -0800
From:	Darren Hart <dvhltc@...ibm.com>
To:	linux-kernel@...r.kernel.org
Subject: [PATCH] RFC: futex fault handling and futex key references (NOT FOR
	INCLUSION)

While trying to bend my brain around the various layers of fault handling in
futex.c, I think I may have uncovered some logical errors (or at least stale
code sections).  I've attached two patches that address the alleged problems
against linux-tip/core/futexes.  They are based on the following assumption:

Since the uaddr passed to a futex function isn't updated within the function,
and the mm doesn't change while we're in there, there should never be a need to
make repeat calls to futex_get_key().  Even if the queue_lock is dropped, the
futex_q might lose it's waiter (requeued) but the key stays the same.

I'd really appreciate any feedback.

Thanks in advance,

---

Darren Hart (2):
      RFC: Fix futex_lock_pi fault handling (NOT FOR INCLUSION)
      RFC: Fix futex_wake_op fault handling (NOT FOR INCLUSION)

 kernel/futex.c |   40 ++++++++++++++++------------------------
 1 files changed, 16 insertions(+), 24 deletions(-)

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