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From: Liu Shuo <shuo.a.liu@intel.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	"Zhang Yanmin" <yanmin_zhang@linux.intel.com>,
	"He Bo" <bo.he@intel.com>, "Liu Shuo" <shuox.liu@gmail.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>
Subject: Re: [PATCH] KVM: release anon file in failure path of vm creation
Date: Fri, 15 Jul 2016 11:18:41 +0800	[thread overview]
Message-ID: <20160715031841.GA20887@shuo-desktop.sh.intel.com> (raw)
In-Reply-To: <20160715022603.GG14480@ZenIV.linux.org.uk>

On Fri 15.Jul'16 at  3:26:03 +0100, Al Viro wrote:
>On Fri, Jul 15, 2016 at 10:22:04AM +0800, Liu Shuo wrote:
>> > You have no warranty whatsoever that descriptor table has not been changed
>> > by that point.  You should *NEVER* use sys_close() on failure exit paths
>> Could you please elaborate why we're not sure descriptor table's changing at the point?
>
>Because that could be called by one thread while another (having guessed the
>descriptor you are about to get) does close()/dup2()/etc.
If there is no such thread (who operates the descriptor based on
guessing), i can think the changing is safe at the point. As the fd has
not been delivered to userspace. Am i right?

  reply	other threads:[~2016-07-15  3:18 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-12  9:38 [PATCH] KVM: release anon file in failure path of vm creation Liu Shuo
2016-07-12 10:24 ` Paolo Bonzini
2016-07-14 16:46   ` Al Viro
2016-07-14 16:56     ` Paolo Bonzini
2016-07-15  2:22     ` Liu Shuo
2016-07-15  2:26       ` Al Viro
2016-07-15  3:18         ` Liu Shuo [this message]
2016-07-15  5:09           ` Al Viro
2016-07-15  7:04             ` Liu Shuo

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