From: "Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>,
xen-devel@lists.xenproject.org,
Stefano Stabellini <sstabellini@kernel.org>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] xen/events: avoid NULL pointer dereference in evtchn_from_irq()
Date: Thu, 21 May 2020 20:46:02 +0200 [thread overview]
Message-ID: <20200521184602.GP98582@mail-itl> (raw)
In-Reply-To: <30719c35-6de7-d400-7bb8-cff4570f8971@oracle.com>
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On Thu, May 21, 2020 at 01:22:03PM -0400, Boris Ostrovsky wrote:
> On 3/19/20 3:14 AM, Juergen Gross wrote:
> > There have been reports of races in evtchn_from_irq() where the info
> > pointer has been NULL.
> >
> > Avoid that case by testing info before dereferencing it.
> >
> > In order to avoid accessing a just freed info structure do the kfree()
> > via kfree_rcu().
>
>
> Looks like noone ever responded to this.
>
>
> This change looks fine but is there a background on the problem? I
> looked in the archives and didn't find the relevant discussion.
Here is the original bug report:
https://xen.markmail.org/thread/44apwkwzeme4uavo
--
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
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WARNING: multiple messages have this Message-ID (diff)
From: "Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>,
xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
Stefano Stabellini <sstabellini@kernel.org>,
stable@vger.kernel.org
Subject: Re: [PATCH] xen/events: avoid NULL pointer dereference in evtchn_from_irq()
Date: Thu, 21 May 2020 20:46:02 +0200 [thread overview]
Message-ID: <20200521184602.GP98582@mail-itl> (raw)
In-Reply-To: <30719c35-6de7-d400-7bb8-cff4570f8971@oracle.com>
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On Thu, May 21, 2020 at 01:22:03PM -0400, Boris Ostrovsky wrote:
> On 3/19/20 3:14 AM, Juergen Gross wrote:
> > There have been reports of races in evtchn_from_irq() where the info
> > pointer has been NULL.
> >
> > Avoid that case by testing info before dereferencing it.
> >
> > In order to avoid accessing a just freed info structure do the kfree()
> > via kfree_rcu().
>
>
> Looks like noone ever responded to this.
>
>
> This change looks fine but is there a background on the problem? I
> looked in the archives and didn't find the relevant discussion.
Here is the original bug report:
https://xen.markmail.org/thread/44apwkwzeme4uavo
--
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
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next prev parent reply other threads:[~2020-05-21 18:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-19 7:14 [Xen-devel] [PATCH] xen/events: avoid NULL pointer dereference in evtchn_from_irq() Juergen Gross
2020-03-19 7:14 ` Juergen Gross
2020-03-19 16:01 ` [Xen-devel] " Boris Ostrovsky
2020-03-19 16:01 ` Boris Ostrovsky
2020-05-21 17:22 ` Boris Ostrovsky
2020-05-21 18:46 ` Marek Marczykowski-Górecki [this message]
2020-05-21 18:46 ` Marek Marczykowski-Górecki
2020-05-21 21:57 ` Boris Ostrovsky
2020-05-21 21:57 ` Boris Ostrovsky
2020-05-22 8:18 ` Jürgen Groß
2020-05-22 8:18 ` Jürgen Groß
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