netdev - Re: kernel panic in skb_copy

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 30 Jun 2013 00:50:50 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Joe Jin <joe.jin@...cle.com>
Cc:	Frank Blaschka <frank.blaschka@...ibm.com>,
	"David S. Miller" <davem@...emloft.net>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"zheng.x.li@...cle.com" <zheng.x.li@...cle.com>,
	Xen Devel <xen-devel@...ts.xen.org>,
	Ian Campbell <Ian.Campbell@...rix.com>,
	Jan Beulich <JBeulich@...e.com>,
	Stefano Stabellini <stefano.stabellini@...citrix.com>
Subject: Re: kernel panic in skb_copy_bits

On Sun, 2013-06-30 at 08:26 +0800, Joe Jin wrote:

> So far we suspected it caused by iscsi called sendpage(), and later page
> be unmapped but still trying copy skb. We'll try to disable sg to see if
> help or no.

sendpage() should increment page refcounts for every page frag of an
skb, therefore page should not be unmapped.

Of course userland can either rewrite the content, or unmap() the page,
but the underlying page cannot be freed as long skb is not freed.



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html