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From: Andrew Morton <akpm@osdl.org>
To: "Sébastien Dugué" <sebastien.dugue@bull.net>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
linux-aio <linux-aio@kvack.org>,
Bharata B Rao <bharata@in.ibm.com>,
Christoph Hellwig <hch@infradead.org>,
Suparna Bhattacharya <suparna@in.ibm.com>,
Ulrich Drepper <drepper@redhat.com>,
Zach Brown <zach.brown@oracle.com>,
Jean Pierre Dion <jean-pierre.dion@bull.net>,
Badari Pulavarty <pbadari@us.ibm.com>
Subject: Re: [PATCH -mm 5/5][AIO] - Add listio syscall support
Date: Tue, 23 Jan 2007 22:04:33 -0800 [thread overview]
Message-ID: <20070123220433.018b40b6.akpm@osdl.org> (raw)
In-Reply-To: <20070117105554.346324b4@frecb000686>
On Wed, 17 Jan 2007 10:55:54 +0100
Sébastien Dugué <sebastien.dugue@bull.net> wrote:
> +void lio_check(struct lio_event *lio)
> +{
> + int ret;
> +
> + ret = atomic_dec_and_test(&lio->lio_users);
> +
> + if (unlikely(ret) && lio->lio_notify.notify != SIGEV_NONE) {
> + /* last one -> notify process */
> + if (aio_send_signal(&lio->lio_notify))
> + sigqueue_free(lio->lio_notify.sigq);
> + kfree(lio);
> + }
> +}
That's a scary function. It may (or may not) free the memory at lio,
returning no indication to the caller whether or not that memory is still
allocated. This is most peculiar - are you really sure there's no
potential for a use-after-free here?
The function is poorly named: I'd expect something called "foo_check" to
not have any side-effects. This one has gross side-effects. Want to think
up a better name, please?
And given that this function has global scope, perhaps a little explanatory
comment is in order?
> +struct lio_event *lio_create(struct sigevent __user *user_event,
> + int mode)
Here too.
next prev parent reply other threads:[~2007-01-24 6:06 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20070117104601.36b2ab18@frecb000686>
2007-01-17 9:48 ` [PATCH -mm 1/5][AIO] - Rework compat_sys_io_submit Sébastien Dugué
2007-01-17 9:48 ` [PATCH -mm 2/5][AIO] - fix aio.h includes Sébastien Dugué
2007-01-17 9:49 ` [PATCH -mm 3/5][AIO] - Make good_sigevent non-static Sébastien Dugué
2007-01-17 9:50 ` [PATCH -mm 4/5][AIO] - AIO completion signal notification Sébastien Dugué
2007-01-24 5:35 ` Andrew Morton
2007-01-24 11:11 ` Sébastien Dugué
2007-01-25 5:42 ` Christoph Hellwig
2007-01-25 8:46 ` Sébastien Dugué
2007-01-17 9:55 ` [PATCH -mm 5/5][AIO] - Add listio syscall support Sébastien Dugué
2007-01-24 5:50 ` Andrew Morton
2007-01-24 11:51 ` Sébastien Dugué
2007-01-24 5:53 ` Andrew Morton
2007-01-24 9:52 ` Laurent Vivier
2007-01-24 11:53 ` Sébastien Dugué
2007-01-24 6:04 ` Andrew Morton [this message]
2007-01-24 12:02 ` Sébastien Dugué
2007-01-24 18:16 ` Bharata B Rao
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