Re: [PATCH net-next] net: adjust skb->truesize in pskb_expand_head()

2017-01-27 Thread Eric Dumazet
On Fri, 2017-01-27 at 17:24 +, David Laight wrote: > From: Eric Dumazet > > Sent: 27 January 2017 14:44 > ... > > > I'm also guessing that extra headroom can be generated by stealing unused > > > tailroom. > > > > This is already done. > > > > Quoting > >

RE: [PATCH net-next] net: adjust skb->truesize in pskb_expand_head()

2017-01-27 Thread David Laight
From: Eric Dumazet > Sent: 27 January 2017 14:44 ... > > I'm also guessing that extra headroom can be generated by stealing unused > > tailroom. > > This is already done. > > Quoting > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=87fb4b7b533073eeeaed0b6bf7c >

Re: [PATCH net-next] net: adjust skb->truesize in pskb_expand_head()

2017-01-27 Thread Eric Dumazet
On Fri, 2017-01-27 at 15:46 +, David Laight wrote: > Reads code ... > My confusion is that the call is specifying the number of EXTRA bytes of > head/tail > room rather than the number of bytes needed. And the fact that @size is changed in existing code (so not visible in patch diff) to

RE: [PATCH net-next] net: adjust skb->truesize in pskb_expand_head()

2017-01-27 Thread David Laight
From: Eric Dumazet [mailto:eric.duma...@gmail.com] > Sent: 27 January 2017 14:44 > On Fri, 2017-01-27 at 10:49 +, David Laight wrote: > > From: Eric Dumazet > > > Sent: 27 January 2017 00:21 > > > Slava Shwartsman reported a warning in skb_try_coalesce(), when we > > > detect skb->truesize is

Re: [PATCH net-next] net: adjust skb->truesize in pskb_expand_head()

2017-01-27 Thread Eric Dumazet
On Fri, 2017-01-27 at 10:49 +, David Laight wrote: > From: Eric Dumazet > > Sent: 27 January 2017 00:21 > > Slava Shwartsman reported a warning in skb_try_coalesce(), when we > > detect skb->truesize is completely wrong. > > > > In his case, issue came from IPv6 reassembly coping with

RE: [PATCH net-next] net: adjust skb->truesize in pskb_expand_head()

2017-01-27 Thread David Laight
From: Eric Dumazet > Sent: 27 January 2017 00:21 > Slava Shwartsman reported a warning in skb_try_coalesce(), when we > detect skb->truesize is completely wrong. > > In his case, issue came from IPv6 reassembly coping with malicious > datagrams, that forced various pskb_may_pull() to reallocate a

Re: [PATCH net-next] net: adjust skb->truesize in pskb_expand_head()

2017-01-26 Thread Eric Dumazet
On Fri, 2017-01-27 at 10:22 +0800, kbuild test robot wrote: > Hi Eric, > > [auto build test WARNING on net-next/master] > > url: > https://github.com/0day-ci/linux/commits/Eric-Dumazet/net-adjust-skb-truesize-in-pskb_expand_head/20170127-082517 > config: i386-randconfig-x0-01270914 (attached

Re: [PATCH net-next] net: adjust skb->truesize in pskb_expand_head()

2017-01-26 Thread kbuild test robot
Hi Eric, [auto build test WARNING on net-next/master] url: https://github.com/0day-ci/linux/commits/Eric-Dumazet/net-adjust-skb-truesize-in-pskb_expand_head/20170127-082517 config: i386-randconfig-x0-01270914 (attached as .config) compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901 reproduce: