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  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:	Sat, 19 Apr 2008 02:35:24 -0700 (PDT)
From:	David Miller <>
Subject: Re: [PATCH] net: add destructor for skb data (rewritten)

From: Rusty Russell <>
Date: Fri, 18 Apr 2008 14:21:25 +1000

> If we want to notify something when an skb is truly finished (such as
> for tun vringfd support), we need a destructor on the data.
> This turns out to be slightly non-trivial as fragments from one skb
> get copied to another skb: if the first skb has a destructor (or its
> parent does) we need to keep a reference to it and destroy it only
> when (all the) children are destroyed.  We add an 'orig' pointer to
> the skb_shared_info to do this.
> But there's currently no way to get from the shinfo to the head (to
> kfree it), so we add a 'len' field.  A better alternative to this
> might be to move the skb_shared_info to before the head of the skb data.
> Note that the destructor is responsible for calling kfree: for the tun
> device, this is critical since the destructor can be called from any
> context and it has to do a copy_to_user, so it queues the skb.
> Signed-off-by: Rusty Russell <>

I'm mostly ambivalent but I will say I'm not happy about all of this
extra state you're adding even though it's "only" to the SKB data
shared-info struct and not sk_buff properly.

Does this handle SKB frags of arbitrary depth?  SKB's can be nested to
arbitrary depths via the frag mechanism.
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists