re: aoe: print warning regarding a common reason for dropped transmits

re: aoe: print warning regarding a common reason for dropped transmits

[Dan Carpenter]

Hello Ed L. Cashin,

The patch 6fde53abc51d: "aoe: print warning regarding a common reason 
for dropped transmits" from Oct 23, 2012, leads to the following 
warning:
drivers/block/aoe/aoenet.c:62 tx()
	 error: 'skb' was already used up by dev_queue_xmit()

61)              if (dev_queue_xmit(skb) = NET_XMIT_DROP && net_ratelimit())
62)                      pr_warn("aoe: packet could not be sent on %s.  %s\n",
63)                              skb->dev ? skb->dev->name : "netif",
64)                              "consider increasing tx_queue_len");

It's a use after free bug.

regards,
dan carpenter

Re: aoe: print warning regarding a common reason for dropped transmits

[Ed Cashin]

On Oct 23, 2012, at 1:28 PM, Dan Carpenter wrote:

> Hello Ed L. Cashin,
> 
> The patch 6fde53abc51d: "aoe: print warning regarding a common reason 
> for dropped transmits" from Oct 23, 2012, leads to the following 
> warning:
> drivers/block/aoe/aoenet.c:62 tx()
> 	 error: 'skb' was already used up by dev_queue_xmit()
> 
> 61)              if (dev_queue_xmit(skb) = NET_XMIT_DROP && net_ratelimit())
> 62)                      pr_warn("aoe: packet could not be sent on %s.  %s\n",
> 63)                              skb->dev ? skb->dev->name : "netif",
> 64)                              "consider increasing tx_queue_len");
> 
> It's a use after free bug.

Thanks for the report.  The Documentation/SubmittingPatches says,

    Please note that this tag should not be added without the
    reporter's permission, especially if the problem was not
    reported in a public forum.

Which surprisingly means that I should ask you for permission before
mentioning you in a "Reported-by:" tag, even though you reported it in
a public forum.  So is it OK?

-- 
  Ed Cashin
  ecashin@coraid.com

Re: aoe: print warning regarding a common reason for dropped transmits

[Dan Carpenter]

On Tue, Oct 23, 2012 at 01:51:33PM -0500, Ed Cashin wrote:
> On Oct 23, 2012, at 1:28 PM, Dan Carpenter wrote:
> 
> > Hello Ed L. Cashin,
> > 
> > The patch 6fde53abc51d: "aoe: print warning regarding a common reason 
> > for dropped transmits" from Oct 23, 2012, leads to the following 
> > warning:
> > drivers/block/aoe/aoenet.c:62 tx()
> > 	 error: 'skb' was already used up by dev_queue_xmit()
> > 
> > 61)              if (dev_queue_xmit(skb) = NET_XMIT_DROP && net_ratelimit())
> > 62)                      pr_warn("aoe: packet could not be sent on %s.  %s\n",
> > 63)                              skb->dev ? skb->dev->name : "netif",
> > 64)                              "consider increasing tx_queue_len");
> > 
> > It's a use after free bug.
> 
> Thanks for the report.  The Documentation/SubmittingPatches says,
> 
>     Please note that this tag should not be added without the
>     reporter's permission, especially if the problem was not
>     reported in a public forum.
> 
> Which surprisingly means that I should ask you for permission before
> mentioning you in a "Reported-by:" tag, even though you reported it in
> a public forum.  So is it OK?

Yes.  Reported-by credits are always welcome.

I think that documentation is wrong.  If the email was reported to a
mailing list or bugzilla then we normally add a reported-by by
default.

regards,
dan carpenter

Re: aoe: print warning regarding a common reason for dropped transmits

[Ed Cashin]

On Oct 24, 2012, at 2:26 AM, Dan Carpenter wrote:

> On Tue, Oct 23, 2012 at 01:51:33PM -0500, Ed Cashin wrote:
>> On Oct 23, 2012, at 1:28 PM, Dan Carpenter wrote:
>> 
>>> Hello Ed L. Cashin,
>>> 
>>> The patch 6fde53abc51d: "aoe: print warning regarding a common reason 
>>> for dropped transmits" from Oct 23, 2012, leads to the following 
>>> warning:
>>> drivers/block/aoe/aoenet.c:62 tx()
>>> 	 error: 'skb' was already used up by dev_queue_xmit()
>>> 
>>> 61)              if (dev_queue_xmit(skb) = NET_XMIT_DROP && net_ratelimit())
>>> 62)                      pr_warn("aoe: packet could not be sent on %s.  %s\n",
>>> 63)                              skb->dev ? skb->dev->name : "netif",
>>> 64)                              "consider increasing tx_queue_len");
>>> 
>>> It's a use after free bug.

By the way, what tool is generating that warning?

Thanks.

-- 
  Ed Cashin
  ecashin@coraid.com