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From: Oleg Nesterov <oleg@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alan Cox <alan@linux.intel.com>, Greg KH <greg@kroah.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Serge Hallyn <serue@us.ibm.com>,
	Sukadev Bhattiprolu <sukadev@us.ibm.com>,
	stable@kernel.org
Subject: Re: [PATCH 1/1] tty: release_one_tty() forgets to put pids
Date: Fri, 2 Apr 2010 20:48:23 +0200	[thread overview]
Message-ID: <20100402184823.GB32229@redhat.com> (raw)
In-Reply-To: <m14ojtogt6.fsf@fess.ebiederm.org>

On 04/02, Eric W. Biederman wrote:
>
> My general paranoia would suggest setting the pids to NULL.  So that
> we don't have the chance of a use after free.

In this case, I don't think this is needed. We are doing
free_tty_struct()->kfree(tty) right after put_pid()s, nobody
can use these pointers or we have another bug.


Most probably this patch is correct (but perhaps it is not the best fix).
Every time tty does put_pid() it should also clear the pointer. But I am
not sure I grepped enough.

Oleg.


  reply	other threads:[~2010-04-02 18:50 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-27 12:21 [2.6.31 and later] "struct pid" leak Tetsuo Handa
2010-03-30 15:31 ` Catalin Marinas
2010-03-31 22:17   ` Andrew Morton
2010-04-01 16:52     ` Oleg Nesterov
2010-04-01 17:21       ` Serge E. Hallyn
2010-04-01 17:33         ` Serge E. Hallyn
2010-04-02 15:29         ` Oleg Nesterov
2010-04-02 16:04     ` [PATCH 0/1] tty: release_one_tty() forgets to put pids Oleg Nesterov
2010-04-02 16:05       ` [PATCH 1/1] " Oleg Nesterov
2010-04-02 16:19         ` Oleg Nesterov
2010-04-02 17:46         ` Linus Torvalds
2010-04-02 18:22           ` Eric W. Biederman
2010-04-02 18:48             ` Oleg Nesterov [this message]
2010-04-02 18:43           ` Oleg Nesterov
2010-04-02 20:09           ` Alan Cox
2010-04-03  2:40       ` [PATCH 0/1] " Tetsuo Handa
2010-04-03  3:08       ` Linus Torvalds
2010-04-03  5:15         ` [stable] " Greg KH

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