netdev - Re: pktgen terminating condition

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]

Message-Id: <20070828.155619.115910106.davem@davemloft.net>
Date:	Tue, 28 Aug 2007 15:56:19 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	msb@...gle.com
Cc:	netdev@...r.kernel.org, grundler@...gle.com, hadi@...erus.ca,
	robert.olsson@....uu.se, venza@...wnhat.org
Subject: Re: pktgen terminating condition

From: Mandeep Singh Baines <msb@...gle.com>
Date: Tue, 28 Aug 2007 15:47:18 -0700

> It seems that some drivers do not immediately free skbs on transmit
> complete.  They will hold the skb until there are more packets to
> free. One example is the sis900 driver which uses TX_IDLE (tx
> state-machine idle) instead of TX_OK (tx completed) as a way of
> coalescing interrupts. I've also seen another driver which does
> something similar. Not sure how prevalent this technique is.
>
> So is this a bug in the drivers or a bug in pktgen?

This is a bug since it can stall TCP sockets, and even non-TCP sockets
will not be freeable until these SKBs are released by the device.

All transmit packets must be released in a finite amount of time by
the driver without requiring more traffic to induce this release.
-
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