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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Joe Jin <joe.jin@oracle.com>
Cc: Frank Blaschka <frank.blaschka@de.ibm.com>,
	"zheng.x.li@oracle.com" <zheng.x.li@oracle.com>,
	Ian Campbell <Ian.Campbell@citrix.com>,
	Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Xen Devel <xen-devel@lists.xen.org>,
	Jan Beulich <JBeulich@suse.com>,
	"David S. Miller" <davem@davemloft.net>
Subject: Re: kernel panic in skb_copy_bits
Date: Sun, 30 Jun 2013 00:50:50 -0700	[thread overview]
Message-ID: <1372578650.3301.305.camel__20157.0536745296$1372578791$gmane$org@edumazet-glaptop> (raw)
In-Reply-To: <51CF7B31.8050408@oracle.com>

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.

  reply	other threads:[~2013-06-30  7:50 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-27  2:58 kernel panic in skb_copy_bits Joe Jin
2013-06-27  2:58 ` Joe Jin
2013-06-27  5:31 ` Eric Dumazet
2013-06-27  5:31   ` Eric Dumazet
2013-06-27  7:15   ` Joe Jin
2013-06-27  7:15     ` Joe Jin
2013-06-28  4:17   ` Joe Jin
2013-06-28  4:17     ` Joe Jin
2013-06-28  6:52     ` Eric Dumazet
2013-06-28  6:52       ` Eric Dumazet
2013-06-28  9:37       ` Eric Dumazet
2013-06-28  9:37       ` Eric Dumazet
2013-06-28 11:33         ` Joe Jin
2013-06-28 11:33         ` Joe Jin
2013-06-28 23:36         ` Joe Jin
2013-06-28 23:36           ` Joe Jin
2013-06-29  7:04           ` Eric Dumazet
2013-06-29  7:04           ` Eric Dumazet
2013-06-29  7:20           ` Eric Dumazet
2013-06-29  7:20           ` Eric Dumazet
2013-06-29  7:20             ` Eric Dumazet
2013-06-29 16:11             ` Ben Greear
2013-06-29 16:11             ` Ben Greear
2013-06-29 16:11               ` Ben Greear
2013-06-29 16:26               ` Eric Dumazet
2013-06-29 16:31                 ` Ben Greear
2013-06-29 16:31                 ` Ben Greear
2013-06-29 16:26               ` Eric Dumazet
2013-06-30  0:26             ` Joe Jin
2013-06-30  0:26               ` Joe Jin
2013-06-30  7:50               ` Eric Dumazet [this message]
2013-06-30  7:50               ` Eric Dumazet
2013-06-30  0:26             ` Joe Jin
2013-06-28 23:36         ` Joe Jin
2013-07-01 20:36         ` David Miller
2013-07-01 20:36         ` David Miller
2013-06-28  6:52     ` Eric Dumazet
2013-06-30  9:13     ` Alex Bligh
2013-06-30  9:13       ` Alex Bligh
2013-06-30  9:35       ` Alex Bligh
2013-06-30  9:35       ` Alex Bligh
2013-07-01  3:18       ` Joe Jin
2013-07-01  8:11         ` Ian Campbell
2013-07-01  8:11         ` Ian Campbell
2013-07-01 13:00           ` Joe Jin
2013-07-01 13:00           ` Joe Jin
2013-07-04  8:55           ` Joe Jin
2013-07-04  8:55           ` Joe Jin
2013-07-04  8:59             ` Ian Campbell
2013-07-04  8:59             ` Ian Campbell
2013-07-04  9:34               ` Eric Dumazet
2013-07-04  9:34               ` Eric Dumazet
2013-07-04  9:52                 ` Ian Campbell
2013-07-04  9:52                 ` Ian Campbell
2013-07-04 10:12                   ` Eric Dumazet
2013-07-04 10:12                   ` Eric Dumazet
2013-07-04 12:57                     ` Alex Bligh
2013-07-04 12:57                     ` Alex Bligh
2013-07-04 21:32                     ` David Miller
2013-07-04 21:32                     ` David Miller
2013-07-01  8:29         ` Alex Bligh
2013-07-01  8:29         ` Alex Bligh
2013-07-01  3:18       ` Joe Jin
2013-06-28  4:17   ` Joe Jin

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