From: Al Viro <viro@ZenIV.linux.org.uk>
To: Leon Ma <xindong.ma@intel.com>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Validate pointer when copying mount namespace.
Date: Wed, 29 Apr 2015 03:36:13 +0100 [thread overview]
Message-ID: <20150429023613.GM889@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1430272604-6701-1-git-send-email-xindong.ma@intel.com>
On Wed, Apr 29, 2015 at 09:56:43AM +0800, Leon Ma wrote:
> We encountered following panic. Validate the pointer to avoid this.
> @@ -2788,7 +2788,7 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns,
> q = next_mnt(q, new);
> if (!q)
> break;
> - while (p->mnt.mnt_root != q->mnt.mnt_root)
> + while (p && p->mnt.mnt_root != q->mnt.mnt_root)
> p = next_mnt(p, old);
> }
> namespace_unlock();
Details, please. How do you reproduce that behaviour?
I don't like that loop in its current form (it relies upon _not_ encountering
the same ->mnt_root in the parts of tree we hadn't copied), but your change
doesn't make it any better. Seeing a reproducer would be useful in sorting
it out; in this form the patch papers over the bug rather than fixing it.
next prev parent reply other threads:[~2015-04-29 2:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-29 1:56 [PATCH] Validate pointer when copying mount namespace Leon Ma
2015-04-29 2:36 ` Al Viro [this message]
2015-04-29 3:21 ` Ma, Xindong
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