On Tue, 10 Jan 2017 10:44:59 -0800 Cong Wang <xiyou.wangc...@gmail.com> wrote:
> On Tue, Jan 10, 2017 at 10:12 AM, David Miller <da...@davemloft.net> wrote: [...] > > You can keep showing us how expertly you can deflect the real > > issue we are discussion here, but that won't improve the situation > > at all I am afraid. > > Of course, there are just too many people too lazy to do a google search: > > https://lists.debian.org/debian-kernel/2013/05/msg00500.html My analysis of the problem shown in above link is not related to using all the stack space, but instead that skb->cb was not cleared. This can cause the ip_options_echo() call in icmp_send() to access garbage as this is: __ip_options_echo(dopt, skb, &IPCB(skb)->opt). Fixed by commit a622260254ee ("ip_tunnel: fix kernel panic with icmp_dest_unreach") https://git.kernel.org/torvalds/c/a622260254ee Thus, it is (likely) the __ip_options_echo() call that violates stack access, as it is passed in a pointer to the stack, and advance this based on garbage "optlen". -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer
